Merge branch 'gs/sq-quote-buf-pretty'
[git] / builtin / rebase.c
1 /*
2  * "git rebase" builtin command
3  *
4  * Copyright (c) 2018 Pratik Karki
5  */
6
7 #define USE_THE_INDEX_COMPATIBILITY_MACROS
8 #include "builtin.h"
9 #include "run-command.h"
10 #include "exec-cmd.h"
11 #include "argv-array.h"
12 #include "dir.h"
13 #include "packfile.h"
14 #include "refs.h"
15 #include "quote.h"
16 #include "config.h"
17 #include "cache-tree.h"
18 #include "unpack-trees.h"
19 #include "lockfile.h"
20 #include "parse-options.h"
21 #include "commit.h"
22 #include "diff.h"
23 #include "wt-status.h"
24 #include "revision.h"
25 #include "commit-reach.h"
26 #include "rerere.h"
27 #include "branch.h"
28 #include "sequencer.h"
29 #include "rebase-interactive.h"
30
31 static char const * const builtin_rebase_usage[] = {
32         N_("git rebase [-i] [options] [--exec <cmd>] "
33                 "[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
34         N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
35                 "--root [<branch>]"),
36         N_("git rebase --continue | --abort | --skip | --edit-todo"),
37         NULL
38 };
39
40 static GIT_PATH_FUNC(path_squash_onto, "rebase-merge/squash-onto")
41 static GIT_PATH_FUNC(path_interactive, "rebase-merge/interactive")
42 static GIT_PATH_FUNC(apply_dir, "rebase-apply")
43 static GIT_PATH_FUNC(merge_dir, "rebase-merge")
44
45 enum rebase_type {
46         REBASE_UNSPECIFIED = -1,
47         REBASE_AM,
48         REBASE_MERGE,
49         REBASE_INTERACTIVE,
50         REBASE_PRESERVE_MERGES
51 };
52
53 struct rebase_options {
54         enum rebase_type type;
55         const char *state_dir;
56         struct commit *upstream;
57         const char *upstream_name;
58         const char *upstream_arg;
59         char *head_name;
60         struct object_id orig_head;
61         struct commit *onto;
62         const char *onto_name;
63         const char *revisions;
64         const char *switch_to;
65         int root, root_with_onto;
66         struct object_id *squash_onto;
67         struct commit *restrict_revision;
68         int dont_finish_rebase;
69         enum {
70                 REBASE_NO_QUIET = 1<<0,
71                 REBASE_VERBOSE = 1<<1,
72                 REBASE_DIFFSTAT = 1<<2,
73                 REBASE_FORCE = 1<<3,
74                 REBASE_INTERACTIVE_EXPLICIT = 1<<4,
75         } flags;
76         struct argv_array git_am_opts;
77         const char *action;
78         int signoff;
79         int allow_rerere_autoupdate;
80         int keep_empty;
81         int autosquash;
82         char *gpg_sign_opt;
83         int autostash;
84         char *cmd;
85         int allow_empty_message;
86         int rebase_merges, rebase_cousins;
87         char *strategy, *strategy_opts;
88         struct strbuf git_format_patch_opt;
89         int reschedule_failed_exec;
90         int use_legacy_rebase;
91 };
92
93 #define REBASE_OPTIONS_INIT {                           \
94                 .type = REBASE_UNSPECIFIED,             \
95                 .flags = REBASE_NO_QUIET,               \
96                 .git_am_opts = ARGV_ARRAY_INIT,         \
97                 .git_format_patch_opt = STRBUF_INIT     \
98         }
99
100 static struct replay_opts get_replay_opts(const struct rebase_options *opts)
101 {
102         struct replay_opts replay = REPLAY_OPTS_INIT;
103
104         replay.action = REPLAY_INTERACTIVE_REBASE;
105         sequencer_init_config(&replay);
106
107         replay.signoff = opts->signoff;
108         replay.allow_ff = !(opts->flags & REBASE_FORCE);
109         if (opts->allow_rerere_autoupdate)
110                 replay.allow_rerere_auto = opts->allow_rerere_autoupdate;
111         replay.allow_empty = 1;
112         replay.allow_empty_message = opts->allow_empty_message;
113         replay.verbose = opts->flags & REBASE_VERBOSE;
114         replay.reschedule_failed_exec = opts->reschedule_failed_exec;
115         replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
116         replay.strategy = opts->strategy;
117         if (opts->strategy_opts)
118                 parse_strategy_opts(&replay, opts->strategy_opts);
119
120         return replay;
121 }
122
123 enum action {
124         ACTION_NONE = 0,
125         ACTION_CONTINUE,
126         ACTION_SKIP,
127         ACTION_ABORT,
128         ACTION_QUIT,
129         ACTION_EDIT_TODO,
130         ACTION_SHOW_CURRENT_PATCH,
131         ACTION_SHORTEN_OIDS,
132         ACTION_EXPAND_OIDS,
133         ACTION_CHECK_TODO_LIST,
134         ACTION_REARRANGE_SQUASH,
135         ACTION_ADD_EXEC
136 };
137
138 static const char *action_names[] = { "undefined",
139                                       "continue",
140                                       "skip",
141                                       "abort",
142                                       "quit",
143                                       "edit_todo",
144                                       "show_current_patch" };
145
146 static int add_exec_commands(struct string_list *commands)
147 {
148         const char *todo_file = rebase_path_todo();
149         struct todo_list todo_list = TODO_LIST_INIT;
150         int res;
151
152         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
153                 return error_errno(_("could not read '%s'."), todo_file);
154
155         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
156                                         &todo_list)) {
157                 todo_list_release(&todo_list);
158                 return error(_("unusable todo list: '%s'"), todo_file);
159         }
160
161         todo_list_add_exec_commands(&todo_list, commands);
162         res = todo_list_write_to_file(the_repository, &todo_list,
163                                       todo_file, NULL, NULL, -1, 0);
164         todo_list_release(&todo_list);
165
166         if (res)
167                 return error_errno(_("could not write '%s'."), todo_file);
168         return 0;
169 }
170
171 static int rearrange_squash_in_todo_file(void)
172 {
173         const char *todo_file = rebase_path_todo();
174         struct todo_list todo_list = TODO_LIST_INIT;
175         int res = 0;
176
177         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
178                 return error_errno(_("could not read '%s'."), todo_file);
179         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
180                                         &todo_list)) {
181                 todo_list_release(&todo_list);
182                 return error(_("unusable todo list: '%s'"), todo_file);
183         }
184
185         res = todo_list_rearrange_squash(&todo_list);
186         if (!res)
187                 res = todo_list_write_to_file(the_repository, &todo_list,
188                                               todo_file, NULL, NULL, -1, 0);
189
190         todo_list_release(&todo_list);
191
192         if (res)
193                 return error_errno(_("could not write '%s'."), todo_file);
194         return 0;
195 }
196
197 static int transform_todo_file(unsigned flags)
198 {
199         const char *todo_file = rebase_path_todo();
200         struct todo_list todo_list = TODO_LIST_INIT;
201         int res;
202
203         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
204                 return error_errno(_("could not read '%s'."), todo_file);
205
206         if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
207                                         &todo_list)) {
208                 todo_list_release(&todo_list);
209                 return error(_("unusable todo list: '%s'"), todo_file);
210         }
211
212         res = todo_list_write_to_file(the_repository, &todo_list, todo_file,
213                                       NULL, NULL, -1, flags);
214         todo_list_release(&todo_list);
215
216         if (res)
217                 return error_errno(_("could not write '%s'."), todo_file);
218         return 0;
219 }
220
221 static int edit_todo_file(unsigned flags)
222 {
223         const char *todo_file = rebase_path_todo();
224         struct todo_list todo_list = TODO_LIST_INIT,
225                 new_todo = TODO_LIST_INIT;
226         int res = 0;
227
228         if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
229                 return error_errno(_("could not read '%s'."), todo_file);
230
231         strbuf_stripspace(&todo_list.buf, 1);
232         res = edit_todo_list(the_repository, &todo_list, &new_todo, NULL, NULL, flags);
233         if (!res && todo_list_write_to_file(the_repository, &new_todo, todo_file,
234                                             NULL, NULL, -1, flags & ~(TODO_LIST_SHORTEN_IDS)))
235                 res = error_errno(_("could not write '%s'"), todo_file);
236
237         todo_list_release(&todo_list);
238         todo_list_release(&new_todo);
239
240         return res;
241 }
242
243 static int get_revision_ranges(struct commit *upstream, struct commit *onto,
244                                const char **head_hash,
245                                char **revisions, char **shortrevisions)
246 {
247         struct commit *base_rev = upstream ? upstream : onto;
248         const char *shorthead;
249         struct object_id orig_head;
250
251         if (get_oid("HEAD", &orig_head))
252                 return error(_("no HEAD?"));
253
254         *head_hash = find_unique_abbrev(&orig_head, GIT_MAX_HEXSZ);
255         *revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid),
256                                                    *head_hash);
257
258         shorthead = find_unique_abbrev(&orig_head, DEFAULT_ABBREV);
259
260         if (upstream) {
261                 const char *shortrev;
262
263                 shortrev = find_unique_abbrev(&base_rev->object.oid,
264                                               DEFAULT_ABBREV);
265
266                 *shortrevisions = xstrfmt("%s..%s", shortrev, shorthead);
267         } else
268                 *shortrevisions = xstrdup(shorthead);
269
270         return 0;
271 }
272
273 static int init_basic_state(struct replay_opts *opts, const char *head_name,
274                             struct commit *onto, const char *orig_head)
275 {
276         FILE *interactive;
277
278         if (!is_directory(merge_dir()) && mkdir_in_gitdir(merge_dir()))
279                 return error_errno(_("could not create temporary %s"), merge_dir());
280
281         delete_reflog("REBASE_HEAD");
282
283         interactive = fopen(path_interactive(), "w");
284         if (!interactive)
285                 return error_errno(_("could not mark as interactive"));
286         fclose(interactive);
287
288         return write_basic_state(opts, head_name, onto, orig_head);
289 }
290
291 static void split_exec_commands(const char *cmd, struct string_list *commands)
292 {
293         if (cmd && *cmd) {
294                 string_list_split(commands, cmd, '\n', -1);
295
296                 /* rebase.c adds a new line to cmd after every command,
297                  * so here the last command is always empty */
298                 string_list_remove_empty_items(commands, 0);
299         }
300 }
301
302 static int do_interactive_rebase(struct rebase_options *opts, unsigned flags)
303 {
304         int ret;
305         const char *head_hash = NULL;
306         char *revisions = NULL, *shortrevisions = NULL;
307         struct argv_array make_script_args = ARGV_ARRAY_INIT;
308         struct todo_list todo_list = TODO_LIST_INIT;
309         struct replay_opts replay = get_replay_opts(opts);
310         struct string_list commands = STRING_LIST_INIT_DUP;
311
312         if (prepare_branch_to_be_rebased(the_repository, &replay,
313                                          opts->switch_to))
314                 return -1;
315
316         if (get_revision_ranges(opts->upstream, opts->onto, &head_hash,
317                                 &revisions, &shortrevisions))
318                 return -1;
319
320         if (init_basic_state(&replay,
321                              opts->head_name ? opts->head_name : "detached HEAD",
322                              opts->onto, head_hash)) {
323                 free(revisions);
324                 free(shortrevisions);
325
326                 return -1;
327         }
328
329         if (!opts->upstream && opts->squash_onto)
330                 write_file(path_squash_onto(), "%s\n",
331                            oid_to_hex(opts->squash_onto));
332
333         argv_array_pushl(&make_script_args, "", revisions, NULL);
334         if (opts->restrict_revision)
335                 argv_array_push(&make_script_args,
336                                 oid_to_hex(&opts->restrict_revision->object.oid));
337
338         ret = sequencer_make_script(the_repository, &todo_list.buf,
339                                     make_script_args.argc, make_script_args.argv,
340                                     flags);
341
342         if (ret)
343                 error(_("could not generate todo list"));
344         else {
345                 discard_cache();
346                 if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
347                                                 &todo_list))
348                         BUG("unusable todo list");
349
350                 split_exec_commands(opts->cmd, &commands);
351                 ret = complete_action(the_repository, &replay, flags,
352                         shortrevisions, opts->onto_name, opts->onto, head_hash,
353                         &commands, opts->autosquash, &todo_list);
354         }
355
356         string_list_clear(&commands, 0);
357         free(revisions);
358         free(shortrevisions);
359         todo_list_release(&todo_list);
360         argv_array_clear(&make_script_args);
361
362         return ret;
363 }
364
365 static int run_rebase_interactive(struct rebase_options *opts,
366                                   enum action command)
367 {
368         unsigned flags = 0;
369         int abbreviate_commands = 0, ret = 0;
370
371         git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
372
373         flags |= opts->keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
374         flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
375         flags |= opts->rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
376         flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
377         flags |= opts->root_with_onto ? TODO_LIST_ROOT_WITH_ONTO : 0;
378         flags |= command == ACTION_SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
379
380         switch (command) {
381         case ACTION_NONE: {
382                 if (!opts->onto && !opts->upstream)
383                         die(_("a base commit must be provided with --upstream or --onto"));
384
385                 ret = do_interactive_rebase(opts, flags);
386                 break;
387         }
388         case ACTION_SKIP: {
389                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
390
391                 rerere_clear(the_repository, &merge_rr);
392         }
393                 /* fallthrough */
394         case ACTION_CONTINUE: {
395                 struct replay_opts replay_opts = get_replay_opts(opts);
396
397                 ret = sequencer_continue(the_repository, &replay_opts);
398                 break;
399         }
400         case ACTION_EDIT_TODO:
401                 ret = edit_todo_file(flags);
402                 break;
403         case ACTION_SHOW_CURRENT_PATCH: {
404                 struct child_process cmd = CHILD_PROCESS_INIT;
405
406                 cmd.git_cmd = 1;
407                 argv_array_pushl(&cmd.args, "show", "REBASE_HEAD", "--", NULL);
408                 ret = run_command(&cmd);
409
410                 break;
411         }
412         case ACTION_SHORTEN_OIDS:
413         case ACTION_EXPAND_OIDS:
414                 ret = transform_todo_file(flags);
415                 break;
416         case ACTION_CHECK_TODO_LIST:
417                 ret = check_todo_list_from_file(the_repository);
418                 break;
419         case ACTION_REARRANGE_SQUASH:
420                 ret = rearrange_squash_in_todo_file();
421                 break;
422         case ACTION_ADD_EXEC: {
423                 struct string_list commands = STRING_LIST_INIT_DUP;
424
425                 split_exec_commands(opts->cmd, &commands);
426                 ret = add_exec_commands(&commands);
427                 string_list_clear(&commands, 0);
428                 break;
429         }
430         default:
431                 BUG("invalid command '%d'", command);
432         }
433
434         return ret;
435 }
436
437 static const char * const builtin_rebase_interactive_usage[] = {
438         N_("git rebase--interactive [<options>]"),
439         NULL
440 };
441
442 int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
443 {
444         struct rebase_options opts = REBASE_OPTIONS_INIT;
445         struct object_id squash_onto = null_oid;
446         enum action command = ACTION_NONE;
447         struct option options[] = {
448                 OPT_NEGBIT(0, "ff", &opts.flags, N_("allow fast-forward"),
449                            REBASE_FORCE),
450                 OPT_BOOL(0, "keep-empty", &opts.keep_empty, N_("keep empty commits")),
451                 OPT_BOOL(0, "allow-empty-message", &opts.allow_empty_message,
452                          N_("allow commits with empty messages")),
453                 OPT_BOOL(0, "rebase-merges", &opts.rebase_merges, N_("rebase merge commits")),
454                 OPT_BOOL(0, "rebase-cousins", &opts.rebase_cousins,
455                          N_("keep original branch points of cousins")),
456                 OPT_BOOL(0, "autosquash", &opts.autosquash,
457                          N_("move commits that begin with squash!/fixup!")),
458                 OPT_BOOL(0, "signoff", &opts.signoff, N_("sign commits")),
459                 OPT_BIT('v', "verbose", &opts.flags,
460                         N_("display a diffstat of what changed upstream"),
461                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
462                 OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
463                             ACTION_CONTINUE),
464                 OPT_CMDMODE(0, "skip", &command, N_("skip commit"), ACTION_SKIP),
465                 OPT_CMDMODE(0, "edit-todo", &command, N_("edit the todo list"),
466                             ACTION_EDIT_TODO),
467                 OPT_CMDMODE(0, "show-current-patch", &command, N_("show the current patch"),
468                             ACTION_SHOW_CURRENT_PATCH),
469                 OPT_CMDMODE(0, "shorten-ids", &command,
470                         N_("shorten commit ids in the todo list"), ACTION_SHORTEN_OIDS),
471                 OPT_CMDMODE(0, "expand-ids", &command,
472                         N_("expand commit ids in the todo list"), ACTION_EXPAND_OIDS),
473                 OPT_CMDMODE(0, "check-todo-list", &command,
474                         N_("check the todo list"), ACTION_CHECK_TODO_LIST),
475                 OPT_CMDMODE(0, "rearrange-squash", &command,
476                         N_("rearrange fixup/squash lines"), ACTION_REARRANGE_SQUASH),
477                 OPT_CMDMODE(0, "add-exec-commands", &command,
478                         N_("insert exec commands in todo list"), ACTION_ADD_EXEC),
479                 { OPTION_CALLBACK, 0, "onto", &opts.onto, N_("onto"), N_("onto"),
480                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
481                 { OPTION_CALLBACK, 0, "restrict-revision", &opts.restrict_revision,
482                   N_("restrict-revision"), N_("restrict revision"),
483                   PARSE_OPT_NONEG, parse_opt_commit, 0 },
484                 { OPTION_CALLBACK, 0, "squash-onto", &squash_onto, N_("squash-onto"),
485                   N_("squash onto"), PARSE_OPT_NONEG, parse_opt_object_id, 0 },
486                 { OPTION_CALLBACK, 0, "upstream", &opts.upstream, N_("upstream"),
487                   N_("the upstream commit"), PARSE_OPT_NONEG, parse_opt_commit,
488                   0 },
489                 OPT_STRING(0, "head-name", &opts.head_name, N_("head-name"), N_("head name")),
490                 { OPTION_STRING, 'S', "gpg-sign", &opts.gpg_sign_opt, N_("key-id"),
491                         N_("GPG-sign commits"),
492                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
493                 OPT_STRING(0, "strategy", &opts.strategy, N_("strategy"),
494                            N_("rebase strategy")),
495                 OPT_STRING(0, "strategy-opts", &opts.strategy_opts, N_("strategy-opts"),
496                            N_("strategy options")),
497                 OPT_STRING(0, "switch-to", &opts.switch_to, N_("switch-to"),
498                            N_("the branch or commit to checkout")),
499                 OPT_STRING(0, "onto-name", &opts.onto_name, N_("onto-name"), N_("onto name")),
500                 OPT_STRING(0, "cmd", &opts.cmd, N_("cmd"), N_("the command to run")),
501                 OPT_RERERE_AUTOUPDATE(&opts.allow_rerere_autoupdate),
502                 OPT_BOOL(0, "reschedule-failed-exec", &opts.reschedule_failed_exec,
503                          N_("automatically re-schedule any `exec` that fails")),
504                 OPT_END()
505         };
506
507         opts.rebase_cousins = -1;
508
509         if (argc == 1)
510                 usage_with_options(builtin_rebase_interactive_usage, options);
511
512         argc = parse_options(argc, argv, prefix, options,
513                         builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
514
515         if (!is_null_oid(&squash_onto))
516                 opts.squash_onto = &squash_onto;
517
518         if (opts.rebase_cousins >= 0 && !opts.rebase_merges)
519                 warning(_("--[no-]rebase-cousins has no effect without "
520                           "--rebase-merges"));
521
522         return !!run_rebase_interactive(&opts, command);
523 }
524
525 static int is_interactive(struct rebase_options *opts)
526 {
527         return opts->type == REBASE_INTERACTIVE ||
528                 opts->type == REBASE_PRESERVE_MERGES;
529 }
530
531 static void imply_interactive(struct rebase_options *opts, const char *option)
532 {
533         switch (opts->type) {
534         case REBASE_AM:
535                 die(_("%s requires an interactive rebase"), option);
536                 break;
537         case REBASE_INTERACTIVE:
538         case REBASE_PRESERVE_MERGES:
539                 break;
540         case REBASE_MERGE:
541                 /* we now implement --merge via --interactive */
542         default:
543                 opts->type = REBASE_INTERACTIVE; /* implied */
544                 break;
545         }
546 }
547
548 /* Returns the filename prefixed by the state_dir */
549 static const char *state_dir_path(const char *filename, struct rebase_options *opts)
550 {
551         static struct strbuf path = STRBUF_INIT;
552         static size_t prefix_len;
553
554         if (!prefix_len) {
555                 strbuf_addf(&path, "%s/", opts->state_dir);
556                 prefix_len = path.len;
557         }
558
559         strbuf_setlen(&path, prefix_len);
560         strbuf_addstr(&path, filename);
561         return path.buf;
562 }
563
564 /* Read one file, then strip line endings */
565 static int read_one(const char *path, struct strbuf *buf)
566 {
567         if (strbuf_read_file(buf, path, 0) < 0)
568                 return error_errno(_("could not read '%s'"), path);
569         strbuf_trim_trailing_newline(buf);
570         return 0;
571 }
572
573 /* Initialize the rebase options from the state directory. */
574 static int read_basic_state(struct rebase_options *opts)
575 {
576         struct strbuf head_name = STRBUF_INIT;
577         struct strbuf buf = STRBUF_INIT;
578         struct object_id oid;
579
580         if (read_one(state_dir_path("head-name", opts), &head_name) ||
581             read_one(state_dir_path("onto", opts), &buf))
582                 return -1;
583         opts->head_name = starts_with(head_name.buf, "refs/") ?
584                 xstrdup(head_name.buf) : NULL;
585         strbuf_release(&head_name);
586         if (get_oid(buf.buf, &oid))
587                 return error(_("could not get 'onto': '%s'"), buf.buf);
588         opts->onto = lookup_commit_or_die(&oid, buf.buf);
589
590         /*
591          * We always write to orig-head, but interactive rebase used to write to
592          * head. Fall back to reading from head to cover for the case that the
593          * user upgraded git with an ongoing interactive rebase.
594          */
595         strbuf_reset(&buf);
596         if (file_exists(state_dir_path("orig-head", opts))) {
597                 if (read_one(state_dir_path("orig-head", opts), &buf))
598                         return -1;
599         } else if (read_one(state_dir_path("head", opts), &buf))
600                 return -1;
601         if (get_oid(buf.buf, &opts->orig_head))
602                 return error(_("invalid orig-head: '%s'"), buf.buf);
603
604         if (file_exists(state_dir_path("quiet", opts)))
605                 opts->flags &= ~REBASE_NO_QUIET;
606         else
607                 opts->flags |= REBASE_NO_QUIET;
608
609         if (file_exists(state_dir_path("verbose", opts)))
610                 opts->flags |= REBASE_VERBOSE;
611
612         if (file_exists(state_dir_path("signoff", opts))) {
613                 opts->signoff = 1;
614                 opts->flags |= REBASE_FORCE;
615         }
616
617         if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
618                 strbuf_reset(&buf);
619                 if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
620                             &buf))
621                         return -1;
622                 if (!strcmp(buf.buf, "--rerere-autoupdate"))
623                         opts->allow_rerere_autoupdate = RERERE_AUTOUPDATE;
624                 else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
625                         opts->allow_rerere_autoupdate = RERERE_NOAUTOUPDATE;
626                 else
627                         warning(_("ignoring invalid allow_rerere_autoupdate: "
628                                   "'%s'"), buf.buf);
629         }
630
631         if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
632                 strbuf_reset(&buf);
633                 if (read_one(state_dir_path("gpg_sign_opt", opts),
634                             &buf))
635                         return -1;
636                 free(opts->gpg_sign_opt);
637                 opts->gpg_sign_opt = xstrdup(buf.buf);
638         }
639
640         if (file_exists(state_dir_path("strategy", opts))) {
641                 strbuf_reset(&buf);
642                 if (read_one(state_dir_path("strategy", opts), &buf))
643                         return -1;
644                 free(opts->strategy);
645                 opts->strategy = xstrdup(buf.buf);
646         }
647
648         if (file_exists(state_dir_path("strategy_opts", opts))) {
649                 strbuf_reset(&buf);
650                 if (read_one(state_dir_path("strategy_opts", opts), &buf))
651                         return -1;
652                 free(opts->strategy_opts);
653                 opts->strategy_opts = xstrdup(buf.buf);
654         }
655
656         strbuf_release(&buf);
657
658         return 0;
659 }
660
661 static int rebase_write_basic_state(struct rebase_options *opts)
662 {
663         write_file(state_dir_path("head-name", opts), "%s",
664                    opts->head_name ? opts->head_name : "detached HEAD");
665         write_file(state_dir_path("onto", opts), "%s",
666                    opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
667         write_file(state_dir_path("orig-head", opts), "%s",
668                    oid_to_hex(&opts->orig_head));
669         write_file(state_dir_path("quiet", opts), "%s",
670                    opts->flags & REBASE_NO_QUIET ? "" : "t");
671         if (opts->flags & REBASE_VERBOSE)
672                 write_file(state_dir_path("verbose", opts), "%s", "");
673         if (opts->strategy)
674                 write_file(state_dir_path("strategy", opts), "%s",
675                            opts->strategy);
676         if (opts->strategy_opts)
677                 write_file(state_dir_path("strategy_opts", opts), "%s",
678                            opts->strategy_opts);
679         if (opts->allow_rerere_autoupdate > 0)
680                 write_file(state_dir_path("allow_rerere_autoupdate", opts),
681                            "-%s-rerere-autoupdate",
682                            opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
683                                 "" : "-no");
684         if (opts->gpg_sign_opt)
685                 write_file(state_dir_path("gpg_sign_opt", opts), "%s",
686                            opts->gpg_sign_opt);
687         if (opts->signoff)
688                 write_file(state_dir_path("strategy", opts), "--signoff");
689
690         return 0;
691 }
692
693 static int apply_autostash(struct rebase_options *opts)
694 {
695         const char *path = state_dir_path("autostash", opts);
696         struct strbuf autostash = STRBUF_INIT;
697         struct child_process stash_apply = CHILD_PROCESS_INIT;
698
699         if (!file_exists(path))
700                 return 0;
701
702         if (read_one(path, &autostash))
703                 return error(_("Could not read '%s'"), path);
704         /* Ensure that the hash is not mistaken for a number */
705         strbuf_addstr(&autostash, "^0");
706         argv_array_pushl(&stash_apply.args,
707                          "stash", "apply", autostash.buf, NULL);
708         stash_apply.git_cmd = 1;
709         stash_apply.no_stderr = stash_apply.no_stdout =
710                 stash_apply.no_stdin = 1;
711         if (!run_command(&stash_apply))
712                 printf(_("Applied autostash.\n"));
713         else {
714                 struct argv_array args = ARGV_ARRAY_INIT;
715                 int res = 0;
716
717                 argv_array_pushl(&args,
718                                  "stash", "store", "-m", "autostash", "-q",
719                                  autostash.buf, NULL);
720                 if (run_command_v_opt(args.argv, RUN_GIT_CMD))
721                         res = error(_("Cannot store %s"), autostash.buf);
722                 argv_array_clear(&args);
723                 strbuf_release(&autostash);
724                 if (res)
725                         return res;
726
727                 fprintf(stderr,
728                         _("Applying autostash resulted in conflicts.\n"
729                           "Your changes are safe in the stash.\n"
730                           "You can run \"git stash pop\" or \"git stash drop\" "
731                           "at any time.\n"));
732         }
733
734         strbuf_release(&autostash);
735         return 0;
736 }
737
738 static int finish_rebase(struct rebase_options *opts)
739 {
740         struct strbuf dir = STRBUF_INIT;
741         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
742         int ret = 0;
743
744         delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
745         apply_autostash(opts);
746         close_object_store(the_repository->objects);
747         /*
748          * We ignore errors in 'gc --auto', since the
749          * user should see them.
750          */
751         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
752         if (opts->type == REBASE_INTERACTIVE) {
753                 struct replay_opts replay = REPLAY_OPTS_INIT;
754
755                 replay.action = REPLAY_INTERACTIVE_REBASE;
756                 ret = sequencer_remove_state(&replay);
757         } else {
758                 strbuf_addstr(&dir, opts->state_dir);
759                 if (remove_dir_recursively(&dir, 0))
760                         ret = error(_("could not remove '%s'"),
761                                     opts->state_dir);
762                 strbuf_release(&dir);
763         }
764
765         return ret;
766 }
767
768 static struct commit *peel_committish(const char *name)
769 {
770         struct object *obj;
771         struct object_id oid;
772
773         if (get_oid(name, &oid))
774                 return NULL;
775         obj = parse_object(the_repository, &oid);
776         return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
777 }
778
779 static void add_var(struct strbuf *buf, const char *name, const char *value)
780 {
781         if (!value)
782                 strbuf_addf(buf, "unset %s; ", name);
783         else {
784                 strbuf_addf(buf, "%s=", name);
785                 sq_quote_buf(buf, value);
786                 strbuf_addstr(buf, "; ");
787         }
788 }
789
790 #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
791
792 #define RESET_HEAD_DETACH (1<<0)
793 #define RESET_HEAD_HARD (1<<1)
794 #define RESET_HEAD_RUN_POST_CHECKOUT_HOOK (1<<2)
795 #define RESET_HEAD_REFS_ONLY (1<<3)
796 #define RESET_ORIG_HEAD (1<<4)
797
798 static int reset_head(struct object_id *oid, const char *action,
799                       const char *switch_to_branch, unsigned flags,
800                       const char *reflog_orig_head, const char *reflog_head)
801 {
802         unsigned detach_head = flags & RESET_HEAD_DETACH;
803         unsigned reset_hard = flags & RESET_HEAD_HARD;
804         unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
805         unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
806         unsigned update_orig_head = flags & RESET_ORIG_HEAD;
807         struct object_id head_oid;
808         struct tree_desc desc[2] = { { NULL }, { NULL } };
809         struct lock_file lock = LOCK_INIT;
810         struct unpack_trees_options unpack_tree_opts;
811         struct tree *tree;
812         const char *reflog_action;
813         struct strbuf msg = STRBUF_INIT;
814         size_t prefix_len;
815         struct object_id *orig = NULL, oid_orig,
816                 *old_orig = NULL, oid_old_orig;
817         int ret = 0, nr = 0;
818
819         if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
820                 BUG("Not a fully qualified branch: '%s'", switch_to_branch);
821
822         if (!refs_only && hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
823                 ret = -1;
824                 goto leave_reset_head;
825         }
826
827         if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
828                 ret = error(_("could not determine HEAD revision"));
829                 goto leave_reset_head;
830         }
831
832         if (!oid)
833                 oid = &head_oid;
834
835         if (refs_only)
836                 goto reset_head_refs;
837
838         memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
839         setup_unpack_trees_porcelain(&unpack_tree_opts, action);
840         unpack_tree_opts.head_idx = 1;
841         unpack_tree_opts.src_index = the_repository->index;
842         unpack_tree_opts.dst_index = the_repository->index;
843         unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
844         unpack_tree_opts.update = 1;
845         unpack_tree_opts.merge = 1;
846         if (!detach_head)
847                 unpack_tree_opts.reset = 1;
848
849         if (repo_read_index_unmerged(the_repository) < 0) {
850                 ret = error(_("could not read index"));
851                 goto leave_reset_head;
852         }
853
854         if (!reset_hard && !fill_tree_descriptor(the_repository, &desc[nr++], &head_oid)) {
855                 ret = error(_("failed to find tree of %s"),
856                             oid_to_hex(&head_oid));
857                 goto leave_reset_head;
858         }
859
860         if (!fill_tree_descriptor(the_repository, &desc[nr++], oid)) {
861                 ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
862                 goto leave_reset_head;
863         }
864
865         if (unpack_trees(nr, desc, &unpack_tree_opts)) {
866                 ret = -1;
867                 goto leave_reset_head;
868         }
869
870         tree = parse_tree_indirect(oid);
871         prime_cache_tree(the_repository, the_repository->index, tree);
872
873         if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
874                 ret = error(_("could not write index"));
875                 goto leave_reset_head;
876         }
877
878 reset_head_refs:
879         reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
880         strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
881         prefix_len = msg.len;
882
883         if (update_orig_head) {
884                 if (!get_oid("ORIG_HEAD", &oid_old_orig))
885                         old_orig = &oid_old_orig;
886                 if (!get_oid("HEAD", &oid_orig)) {
887                         orig = &oid_orig;
888                         if (!reflog_orig_head) {
889                                 strbuf_addstr(&msg, "updating ORIG_HEAD");
890                                 reflog_orig_head = msg.buf;
891                         }
892                         update_ref(reflog_orig_head, "ORIG_HEAD", orig,
893                                    old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
894                 } else if (old_orig)
895                         delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
896         }
897
898         if (!reflog_head) {
899                 strbuf_setlen(&msg, prefix_len);
900                 strbuf_addstr(&msg, "updating HEAD");
901                 reflog_head = msg.buf;
902         }
903         if (!switch_to_branch)
904                 ret = update_ref(reflog_head, "HEAD", oid, orig,
905                                  detach_head ? REF_NO_DEREF : 0,
906                                  UPDATE_REFS_MSG_ON_ERR);
907         else {
908                 ret = update_ref(reflog_head, switch_to_branch, oid,
909                                  NULL, 0, UPDATE_REFS_MSG_ON_ERR);
910                 if (!ret)
911                         ret = create_symref("HEAD", switch_to_branch,
912                                             reflog_head);
913         }
914         if (run_hook)
915                 run_hook_le(NULL, "post-checkout",
916                             oid_to_hex(orig ? orig : &null_oid),
917                             oid_to_hex(oid), "1", NULL);
918
919 leave_reset_head:
920         strbuf_release(&msg);
921         rollback_lock_file(&lock);
922         while (nr)
923                 free((void *)desc[--nr].buffer);
924         return ret;
925 }
926
927 static int move_to_original_branch(struct rebase_options *opts)
928 {
929         struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
930         int ret;
931
932         if (!opts->head_name)
933                 return 0; /* nothing to move back to */
934
935         if (!opts->onto)
936                 BUG("move_to_original_branch without onto");
937
938         strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
939                     opts->head_name, oid_to_hex(&opts->onto->object.oid));
940         strbuf_addf(&head_reflog, "rebase finished: returning to %s",
941                     opts->head_name);
942         ret = reset_head(NULL, "", opts->head_name, RESET_HEAD_REFS_ONLY,
943                          orig_head_reflog.buf, head_reflog.buf);
944
945         strbuf_release(&orig_head_reflog);
946         strbuf_release(&head_reflog);
947         return ret;
948 }
949
950 static const char *resolvemsg =
951 N_("Resolve all conflicts manually, mark them as resolved with\n"
952 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
953 "You can instead skip this commit: run \"git rebase --skip\".\n"
954 "To abort and get back to the state before \"git rebase\", run "
955 "\"git rebase --abort\".");
956
957 static int run_am(struct rebase_options *opts)
958 {
959         struct child_process am = CHILD_PROCESS_INIT;
960         struct child_process format_patch = CHILD_PROCESS_INIT;
961         struct strbuf revisions = STRBUF_INIT;
962         int status;
963         char *rebased_patches;
964
965         am.git_cmd = 1;
966         argv_array_push(&am.args, "am");
967
968         if (opts->action && !strcmp("continue", opts->action)) {
969                 argv_array_push(&am.args, "--resolved");
970                 argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
971                 if (opts->gpg_sign_opt)
972                         argv_array_push(&am.args, opts->gpg_sign_opt);
973                 status = run_command(&am);
974                 if (status)
975                         return status;
976
977                 return move_to_original_branch(opts);
978         }
979         if (opts->action && !strcmp("skip", opts->action)) {
980                 argv_array_push(&am.args, "--skip");
981                 argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
982                 status = run_command(&am);
983                 if (status)
984                         return status;
985
986                 return move_to_original_branch(opts);
987         }
988         if (opts->action && !strcmp("show-current-patch", opts->action)) {
989                 argv_array_push(&am.args, "--show-current-patch");
990                 return run_command(&am);
991         }
992
993         strbuf_addf(&revisions, "%s...%s",
994                     oid_to_hex(opts->root ?
995                                /* this is now equivalent to !opts->upstream */
996                                &opts->onto->object.oid :
997                                &opts->upstream->object.oid),
998                     oid_to_hex(&opts->orig_head));
999
1000         rebased_patches = xstrdup(git_path("rebased-patches"));
1001         format_patch.out = open(rebased_patches,
1002                                 O_WRONLY | O_CREAT | O_TRUNC, 0666);
1003         if (format_patch.out < 0) {
1004                 status = error_errno(_("could not open '%s' for writing"),
1005                                      rebased_patches);
1006                 free(rebased_patches);
1007                 argv_array_clear(&am.args);
1008                 return status;
1009         }
1010
1011         format_patch.git_cmd = 1;
1012         argv_array_pushl(&format_patch.args, "format-patch", "-k", "--stdout",
1013                          "--full-index", "--cherry-pick", "--right-only",
1014                          "--src-prefix=a/", "--dst-prefix=b/", "--no-renames",
1015                          "--no-cover-letter", "--pretty=mboxrd", "--topo-order", NULL);
1016         if (opts->git_format_patch_opt.len)
1017                 argv_array_split(&format_patch.args,
1018                                  opts->git_format_patch_opt.buf);
1019         argv_array_push(&format_patch.args, revisions.buf);
1020         if (opts->restrict_revision)
1021                 argv_array_pushf(&format_patch.args, "^%s",
1022                                  oid_to_hex(&opts->restrict_revision->object.oid));
1023
1024         status = run_command(&format_patch);
1025         if (status) {
1026                 unlink(rebased_patches);
1027                 free(rebased_patches);
1028                 argv_array_clear(&am.args);
1029
1030                 reset_head(&opts->orig_head, "checkout", opts->head_name, 0,
1031                            "HEAD", NULL);
1032                 error(_("\ngit encountered an error while preparing the "
1033                         "patches to replay\n"
1034                         "these revisions:\n"
1035                         "\n    %s\n\n"
1036                         "As a result, git cannot rebase them."),
1037                       opts->revisions);
1038
1039                 strbuf_release(&revisions);
1040                 return status;
1041         }
1042         strbuf_release(&revisions);
1043
1044         am.in = open(rebased_patches, O_RDONLY);
1045         if (am.in < 0) {
1046                 status = error_errno(_("could not open '%s' for reading"),
1047                                      rebased_patches);
1048                 free(rebased_patches);
1049                 argv_array_clear(&am.args);
1050                 return status;
1051         }
1052
1053         argv_array_pushv(&am.args, opts->git_am_opts.argv);
1054         argv_array_push(&am.args, "--rebasing");
1055         argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
1056         argv_array_push(&am.args, "--patch-format=mboxrd");
1057         if (opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE)
1058                 argv_array_push(&am.args, "--rerere-autoupdate");
1059         else if (opts->allow_rerere_autoupdate == RERERE_NOAUTOUPDATE)
1060                 argv_array_push(&am.args, "--no-rerere-autoupdate");
1061         if (opts->gpg_sign_opt)
1062                 argv_array_push(&am.args, opts->gpg_sign_opt);
1063         status = run_command(&am);
1064         unlink(rebased_patches);
1065         free(rebased_patches);
1066
1067         if (!status) {
1068                 return move_to_original_branch(opts);
1069         }
1070
1071         if (is_directory(opts->state_dir))
1072                 rebase_write_basic_state(opts);
1073
1074         return status;
1075 }
1076
1077 static int run_specific_rebase(struct rebase_options *opts, enum action action)
1078 {
1079         const char *argv[] = { NULL, NULL };
1080         struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
1081         int status;
1082         const char *backend, *backend_func;
1083
1084         if (opts->type == REBASE_INTERACTIVE) {
1085                 /* Run builtin interactive rebase */
1086                 setenv("GIT_CHERRY_PICK_HELP", resolvemsg, 1);
1087                 if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
1088                         setenv("GIT_SEQUENCE_EDITOR", ":", 1);
1089                         opts->autosquash = 0;
1090                 }
1091                 if (opts->gpg_sign_opt) {
1092                         /* remove the leading "-S" */
1093                         char *tmp = xstrdup(opts->gpg_sign_opt + 2);
1094                         free(opts->gpg_sign_opt);
1095                         opts->gpg_sign_opt = tmp;
1096                 }
1097
1098                 status = run_rebase_interactive(opts, action);
1099                 goto finished_rebase;
1100         }
1101
1102         if (opts->type == REBASE_AM) {
1103                 status = run_am(opts);
1104                 goto finished_rebase;
1105         }
1106
1107         add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
1108         add_var(&script_snippet, "state_dir", opts->state_dir);
1109
1110         add_var(&script_snippet, "upstream_name", opts->upstream_name);
1111         add_var(&script_snippet, "upstream", opts->upstream ?
1112                 oid_to_hex(&opts->upstream->object.oid) : NULL);
1113         add_var(&script_snippet, "head_name",
1114                 opts->head_name ? opts->head_name : "detached HEAD");
1115         add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
1116         add_var(&script_snippet, "onto", opts->onto ?
1117                 oid_to_hex(&opts->onto->object.oid) : NULL);
1118         add_var(&script_snippet, "onto_name", opts->onto_name);
1119         add_var(&script_snippet, "revisions", opts->revisions);
1120         add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
1121                 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
1122         add_var(&script_snippet, "GIT_QUIET",
1123                 opts->flags & REBASE_NO_QUIET ? "" : "t");
1124         sq_quote_argv_pretty(&buf, opts->git_am_opts.argv);
1125         add_var(&script_snippet, "git_am_opt", buf.buf);
1126         strbuf_release(&buf);
1127         add_var(&script_snippet, "verbose",
1128                 opts->flags & REBASE_VERBOSE ? "t" : "");
1129         add_var(&script_snippet, "diffstat",
1130                 opts->flags & REBASE_DIFFSTAT ? "t" : "");
1131         add_var(&script_snippet, "force_rebase",
1132                 opts->flags & REBASE_FORCE ? "t" : "");
1133         if (opts->switch_to)
1134                 add_var(&script_snippet, "switch_to", opts->switch_to);
1135         add_var(&script_snippet, "action", opts->action ? opts->action : "");
1136         add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
1137         add_var(&script_snippet, "allow_rerere_autoupdate",
1138                 opts->allow_rerere_autoupdate ?
1139                         opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
1140                         "--rerere-autoupdate" : "--no-rerere-autoupdate" : "");
1141         add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
1142         add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
1143         add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
1144         add_var(&script_snippet, "cmd", opts->cmd);
1145         add_var(&script_snippet, "allow_empty_message",
1146                 opts->allow_empty_message ?  "--allow-empty-message" : "");
1147         add_var(&script_snippet, "rebase_merges",
1148                 opts->rebase_merges ? "t" : "");
1149         add_var(&script_snippet, "rebase_cousins",
1150                 opts->rebase_cousins ? "t" : "");
1151         add_var(&script_snippet, "strategy", opts->strategy);
1152         add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
1153         add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
1154         add_var(&script_snippet, "squash_onto",
1155                 opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
1156         add_var(&script_snippet, "git_format_patch_opt",
1157                 opts->git_format_patch_opt.buf);
1158
1159         if (is_interactive(opts) &&
1160             !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
1161                 strbuf_addstr(&script_snippet,
1162                               "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
1163                 opts->autosquash = 0;
1164         }
1165
1166         switch (opts->type) {
1167         case REBASE_PRESERVE_MERGES:
1168                 backend = "git-rebase--preserve-merges";
1169                 backend_func = "git_rebase__preserve_merges";
1170                 break;
1171         default:
1172                 BUG("Unhandled rebase type %d", opts->type);
1173                 break;
1174         }
1175
1176         strbuf_addf(&script_snippet,
1177                     ". git-sh-setup && . %s && %s", backend, backend_func);
1178         argv[0] = script_snippet.buf;
1179
1180         status = run_command_v_opt(argv, RUN_USING_SHELL);
1181 finished_rebase:
1182         if (opts->dont_finish_rebase)
1183                 ; /* do nothing */
1184         else if (opts->type == REBASE_INTERACTIVE)
1185                 ; /* interactive rebase cleans up after itself */
1186         else if (status == 0) {
1187                 if (!file_exists(state_dir_path("stopped-sha", opts)))
1188                         finish_rebase(opts);
1189         } else if (status == 2) {
1190                 struct strbuf dir = STRBUF_INIT;
1191
1192                 apply_autostash(opts);
1193                 strbuf_addstr(&dir, opts->state_dir);
1194                 remove_dir_recursively(&dir, 0);
1195                 strbuf_release(&dir);
1196                 die("Nothing to do");
1197         }
1198
1199         strbuf_release(&script_snippet);
1200
1201         return status ? -1 : 0;
1202 }
1203
1204 static int rebase_config(const char *var, const char *value, void *data)
1205 {
1206         struct rebase_options *opts = data;
1207
1208         if (!strcmp(var, "rebase.stat")) {
1209                 if (git_config_bool(var, value))
1210                         opts->flags |= REBASE_DIFFSTAT;
1211                 else
1212                         opts->flags &= ~REBASE_DIFFSTAT;
1213                 return 0;
1214         }
1215
1216         if (!strcmp(var, "rebase.autosquash")) {
1217                 opts->autosquash = git_config_bool(var, value);
1218                 return 0;
1219         }
1220
1221         if (!strcmp(var, "commit.gpgsign")) {
1222                 free(opts->gpg_sign_opt);
1223                 opts->gpg_sign_opt = git_config_bool(var, value) ?
1224                         xstrdup("-S") : NULL;
1225                 return 0;
1226         }
1227
1228         if (!strcmp(var, "rebase.autostash")) {
1229                 opts->autostash = git_config_bool(var, value);
1230                 return 0;
1231         }
1232
1233         if (!strcmp(var, "rebase.reschedulefailedexec")) {
1234                 opts->reschedule_failed_exec = git_config_bool(var, value);
1235                 return 0;
1236         }
1237
1238         if (!strcmp(var, "rebase.usebuiltin")) {
1239                 opts->use_legacy_rebase = !git_config_bool(var, value);
1240                 return 0;
1241         }
1242
1243         return git_default_config(var, value, data);
1244 }
1245
1246 /*
1247  * Determines whether the commits in from..to are linear, i.e. contain
1248  * no merge commits. This function *expects* `from` to be an ancestor of
1249  * `to`.
1250  */
1251 static int is_linear_history(struct commit *from, struct commit *to)
1252 {
1253         while (to && to != from) {
1254                 parse_commit(to);
1255                 if (!to->parents)
1256                         return 1;
1257                 if (to->parents->next)
1258                         return 0;
1259                 to = to->parents->item;
1260         }
1261         return 1;
1262 }
1263
1264 static int can_fast_forward(struct commit *onto, struct commit *upstream,
1265                             struct commit *restrict_revision,
1266                             struct object_id *head_oid, struct object_id *merge_base)
1267 {
1268         struct commit *head = lookup_commit(the_repository, head_oid);
1269         struct commit_list *merge_bases = NULL;
1270         int res = 0;
1271
1272         if (!head)
1273                 goto done;
1274
1275         merge_bases = get_merge_bases(onto, head);
1276         if (!merge_bases || merge_bases->next) {
1277                 oidcpy(merge_base, &null_oid);
1278                 goto done;
1279         }
1280
1281         oidcpy(merge_base, &merge_bases->item->object.oid);
1282         if (!oideq(merge_base, &onto->object.oid))
1283                 goto done;
1284
1285         if (restrict_revision && !oideq(&restrict_revision->object.oid, merge_base))
1286                 goto done;
1287
1288         if (!upstream)
1289                 goto done;
1290
1291         free_commit_list(merge_bases);
1292         merge_bases = get_merge_bases(upstream, head);
1293         if (!merge_bases || merge_bases->next)
1294                 goto done;
1295
1296         if (!oideq(&onto->object.oid, &merge_bases->item->object.oid))
1297                 goto done;
1298
1299         res = 1;
1300
1301 done:
1302         free_commit_list(merge_bases);
1303         return res && is_linear_history(onto, head);
1304 }
1305
1306 /* -i followed by -m is still -i */
1307 static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
1308 {
1309         struct rebase_options *opts = opt->value;
1310
1311         BUG_ON_OPT_NEG(unset);
1312         BUG_ON_OPT_ARG(arg);
1313
1314         if (!is_interactive(opts))
1315                 opts->type = REBASE_MERGE;
1316
1317         return 0;
1318 }
1319
1320 /* -i followed by -p is still explicitly interactive, but -p alone is not */
1321 static int parse_opt_interactive(const struct option *opt, const char *arg,
1322                                  int unset)
1323 {
1324         struct rebase_options *opts = opt->value;
1325
1326         BUG_ON_OPT_NEG(unset);
1327         BUG_ON_OPT_ARG(arg);
1328
1329         opts->type = REBASE_INTERACTIVE;
1330         opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
1331
1332         return 0;
1333 }
1334
1335 static void NORETURN error_on_missing_default_upstream(void)
1336 {
1337         struct branch *current_branch = branch_get(NULL);
1338
1339         printf(_("%s\n"
1340                  "Please specify which branch you want to rebase against.\n"
1341                  "See git-rebase(1) for details.\n"
1342                  "\n"
1343                  "    git rebase '<branch>'\n"
1344                  "\n"),
1345                 current_branch ? _("There is no tracking information for "
1346                         "the current branch.") :
1347                         _("You are not currently on a branch."));
1348
1349         if (current_branch) {
1350                 const char *remote = current_branch->remote_name;
1351
1352                 if (!remote)
1353                         remote = _("<remote>");
1354
1355                 printf(_("If you wish to set tracking information for this "
1356                          "branch you can do so with:\n"
1357                          "\n"
1358                          "    git branch --set-upstream-to=%s/<branch> %s\n"
1359                          "\n"),
1360                        remote, current_branch->name);
1361         }
1362         exit(1);
1363 }
1364
1365 static void set_reflog_action(struct rebase_options *options)
1366 {
1367         const char *env;
1368         struct strbuf buf = STRBUF_INIT;
1369
1370         if (!is_interactive(options))
1371                 return;
1372
1373         env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
1374         if (env && strcmp("rebase", env))
1375                 return; /* only override it if it is "rebase" */
1376
1377         strbuf_addf(&buf, "rebase -i (%s)", options->action);
1378         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
1379         strbuf_release(&buf);
1380 }
1381
1382 static int check_exec_cmd(const char *cmd)
1383 {
1384         if (strchr(cmd, '\n'))
1385                 return error(_("exec commands cannot contain newlines"));
1386
1387         /* Does the command consist purely of whitespace? */
1388         if (!cmd[strspn(cmd, " \t\r\f\v")])
1389                 return error(_("empty exec command"));
1390
1391         return 0;
1392 }
1393
1394
1395 int cmd_rebase(int argc, const char **argv, const char *prefix)
1396 {
1397         struct rebase_options options = REBASE_OPTIONS_INIT;
1398         const char *branch_name;
1399         int ret, flags, total_argc, in_progress = 0;
1400         int keep_base = 0;
1401         int ok_to_skip_pre_rebase = 0;
1402         struct strbuf msg = STRBUF_INIT;
1403         struct strbuf revisions = STRBUF_INIT;
1404         struct strbuf buf = STRBUF_INIT;
1405         struct object_id merge_base;
1406         enum action action = ACTION_NONE;
1407         const char *gpg_sign = NULL;
1408         struct string_list exec = STRING_LIST_INIT_NODUP;
1409         const char *rebase_merges = NULL;
1410         int fork_point = -1;
1411         struct string_list strategy_options = STRING_LIST_INIT_NODUP;
1412         struct object_id squash_onto;
1413         char *squash_onto_name = NULL;
1414         int reschedule_failed_exec = -1;
1415         struct option builtin_rebase_options[] = {
1416                 OPT_STRING(0, "onto", &options.onto_name,
1417                            N_("revision"),
1418                            N_("rebase onto given branch instead of upstream")),
1419                 OPT_BOOL(0, "keep-base", &keep_base,
1420                          N_("use the merge-base of upstream and branch as the current base")),
1421                 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
1422                          N_("allow pre-rebase hook to run")),
1423                 OPT_NEGBIT('q', "quiet", &options.flags,
1424                            N_("be quiet. implies --no-stat"),
1425                            REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
1426                 OPT_BIT('v', "verbose", &options.flags,
1427                         N_("display a diffstat of what changed upstream"),
1428                         REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
1429                 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
1430                         N_("do not show diffstat of what changed upstream"),
1431                         PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
1432                 OPT_BOOL(0, "signoff", &options.signoff,
1433                          N_("add a Signed-off-by: line to each commit")),
1434                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &options.git_am_opts,
1435                                   NULL, N_("passed to 'git am'"),
1436                                   PARSE_OPT_NOARG),
1437                 OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
1438                                   &options.git_am_opts, NULL,
1439                                   N_("passed to 'git am'"), PARSE_OPT_NOARG),
1440                 OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
1441                                   N_("passed to 'git am'"), PARSE_OPT_NOARG),
1442                 OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
1443                                   N_("passed to 'git apply'"), 0),
1444                 OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
1445                                   N_("action"), N_("passed to 'git apply'"), 0),
1446                 OPT_BIT('f', "force-rebase", &options.flags,
1447                         N_("cherry-pick all commits, even if unchanged"),
1448                         REBASE_FORCE),
1449                 OPT_BIT(0, "no-ff", &options.flags,
1450                         N_("cherry-pick all commits, even if unchanged"),
1451                         REBASE_FORCE),
1452                 OPT_CMDMODE(0, "continue", &action, N_("continue"),
1453                             ACTION_CONTINUE),
1454                 OPT_CMDMODE(0, "skip", &action,
1455                             N_("skip current patch and continue"), ACTION_SKIP),
1456                 OPT_CMDMODE(0, "abort", &action,
1457                             N_("abort and check out the original branch"),
1458                             ACTION_ABORT),
1459                 OPT_CMDMODE(0, "quit", &action,
1460                             N_("abort but keep HEAD where it is"), ACTION_QUIT),
1461                 OPT_CMDMODE(0, "edit-todo", &action, N_("edit the todo list "
1462                             "during an interactive rebase"), ACTION_EDIT_TODO),
1463                 OPT_CMDMODE(0, "show-current-patch", &action,
1464                             N_("show the patch file being applied or merged"),
1465                             ACTION_SHOW_CURRENT_PATCH),
1466                 { OPTION_CALLBACK, 'm', "merge", &options, NULL,
1467                         N_("use merging strategies to rebase"),
1468                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1469                         parse_opt_merge },
1470                 { OPTION_CALLBACK, 'i', "interactive", &options, NULL,
1471                         N_("let the user edit the list of commits to rebase"),
1472                         PARSE_OPT_NOARG | PARSE_OPT_NONEG,
1473                         parse_opt_interactive },
1474                 OPT_SET_INT('p', "preserve-merges", &options.type,
1475                             N_("(DEPRECATED) try to recreate merges instead of "
1476                                "ignoring them"), REBASE_PRESERVE_MERGES),
1477                 OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
1478                 OPT_BOOL('k', "keep-empty", &options.keep_empty,
1479                          N_("preserve empty commits during rebase")),
1480                 OPT_BOOL(0, "autosquash", &options.autosquash,
1481                          N_("move commits that begin with "
1482                             "squash!/fixup! under -i")),
1483                 { OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
1484                         N_("GPG-sign commits"),
1485                         PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
1486                 OPT_BOOL(0, "autostash", &options.autostash,
1487                          N_("automatically stash/stash pop before and after")),
1488                 OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
1489                                 N_("add exec lines after each commit of the "
1490                                    "editable list")),
1491                 OPT_BOOL(0, "allow-empty-message",
1492                          &options.allow_empty_message,
1493                          N_("allow rebasing commits with empty messages")),
1494                 {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
1495                         N_("mode"),
1496                         N_("try to rebase merges instead of skipping them"),
1497                         PARSE_OPT_OPTARG, NULL, (intptr_t)""},
1498                 OPT_BOOL(0, "fork-point", &fork_point,
1499                          N_("use 'merge-base --fork-point' to refine upstream")),
1500                 OPT_STRING('s', "strategy", &options.strategy,
1501                            N_("strategy"), N_("use the given merge strategy")),
1502                 OPT_STRING_LIST('X', "strategy-option", &strategy_options,
1503                                 N_("option"),
1504                                 N_("pass the argument through to the merge "
1505                                    "strategy")),
1506                 OPT_BOOL(0, "root", &options.root,
1507                          N_("rebase all reachable commits up to the root(s)")),
1508                 OPT_BOOL(0, "reschedule-failed-exec",
1509                          &reschedule_failed_exec,
1510                          N_("automatically re-schedule any `exec` that fails")),
1511                 OPT_END(),
1512         };
1513         int i;
1514
1515         if (argc == 2 && !strcmp(argv[1], "-h"))
1516                 usage_with_options(builtin_rebase_usage,
1517                                    builtin_rebase_options);
1518
1519         options.allow_empty_message = 1;
1520         git_config(rebase_config, &options);
1521
1522         if (options.use_legacy_rebase ||
1523             !git_env_bool("GIT_TEST_REBASE_USE_BUILTIN", -1))
1524                 warning(_("the rebase.useBuiltin support has been removed!\n"
1525                           "See its entry in 'git help config' for details."));
1526
1527         strbuf_reset(&buf);
1528         strbuf_addf(&buf, "%s/applying", apply_dir());
1529         if(file_exists(buf.buf))
1530                 die(_("It looks like 'git am' is in progress. Cannot rebase."));
1531
1532         if (is_directory(apply_dir())) {
1533                 options.type = REBASE_AM;
1534                 options.state_dir = apply_dir();
1535         } else if (is_directory(merge_dir())) {
1536                 strbuf_reset(&buf);
1537                 strbuf_addf(&buf, "%s/rewritten", merge_dir());
1538                 if (is_directory(buf.buf)) {
1539                         options.type = REBASE_PRESERVE_MERGES;
1540                         options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1541                 } else {
1542                         strbuf_reset(&buf);
1543                         strbuf_addf(&buf, "%s/interactive", merge_dir());
1544                         if(file_exists(buf.buf)) {
1545                                 options.type = REBASE_INTERACTIVE;
1546                                 options.flags |= REBASE_INTERACTIVE_EXPLICIT;
1547                         } else
1548                                 options.type = REBASE_MERGE;
1549                 }
1550                 options.state_dir = merge_dir();
1551         }
1552
1553         if (options.type != REBASE_UNSPECIFIED)
1554                 in_progress = 1;
1555
1556         total_argc = argc;
1557         argc = parse_options(argc, argv, prefix,
1558                              builtin_rebase_options,
1559                              builtin_rebase_usage, 0);
1560
1561         if (action != ACTION_NONE && total_argc != 2) {
1562                 usage_with_options(builtin_rebase_usage,
1563                                    builtin_rebase_options);
1564         }
1565
1566         if (argc > 2)
1567                 usage_with_options(builtin_rebase_usage,
1568                                    builtin_rebase_options);
1569
1570         if (options.type == REBASE_PRESERVE_MERGES)
1571                 warning(_("git rebase --preserve-merges is deprecated. "
1572                           "Use --rebase-merges instead."));
1573
1574         if (keep_base) {
1575                 if (options.onto_name)
1576                         die(_("cannot combine '--keep-base' with '--onto'"));
1577                 if (options.root)
1578                         die(_("cannot combine '--keep-base' with '--root'"));
1579         }
1580
1581         if (action != ACTION_NONE && !in_progress)
1582                 die(_("No rebase in progress?"));
1583         setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
1584
1585         if (action == ACTION_EDIT_TODO && !is_interactive(&options))
1586                 die(_("The --edit-todo action can only be used during "
1587                       "interactive rebase."));
1588
1589         if (trace2_is_enabled()) {
1590                 if (is_interactive(&options))
1591                         trace2_cmd_mode("interactive");
1592                 else if (exec.nr)
1593                         trace2_cmd_mode("interactive-exec");
1594                 else
1595                         trace2_cmd_mode(action_names[action]);
1596         }
1597
1598         switch (action) {
1599         case ACTION_CONTINUE: {
1600                 struct object_id head;
1601                 struct lock_file lock_file = LOCK_INIT;
1602                 int fd;
1603
1604                 options.action = "continue";
1605                 set_reflog_action(&options);
1606
1607                 /* Sanity check */
1608                 if (get_oid("HEAD", &head))
1609                         die(_("Cannot read HEAD"));
1610
1611                 fd = hold_locked_index(&lock_file, 0);
1612                 if (repo_read_index(the_repository) < 0)
1613                         die(_("could not read index"));
1614                 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
1615                               NULL);
1616                 if (0 <= fd)
1617                         repo_update_index_if_able(the_repository, &lock_file);
1618                 rollback_lock_file(&lock_file);
1619
1620                 if (has_unstaged_changes(the_repository, 1)) {
1621                         puts(_("You must edit all merge conflicts and then\n"
1622                                "mark them as resolved using git add"));
1623                         exit(1);
1624                 }
1625                 if (read_basic_state(&options))
1626                         exit(1);
1627                 goto run_rebase;
1628         }
1629         case ACTION_SKIP: {
1630                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1631
1632                 options.action = "skip";
1633                 set_reflog_action(&options);
1634
1635                 rerere_clear(the_repository, &merge_rr);
1636                 string_list_clear(&merge_rr, 1);
1637
1638                 if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
1639                                NULL, NULL) < 0)
1640                         die(_("could not discard worktree changes"));
1641                 remove_branch_state(the_repository, 0);
1642                 if (read_basic_state(&options))
1643                         exit(1);
1644                 goto run_rebase;
1645         }
1646         case ACTION_ABORT: {
1647                 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1648                 options.action = "abort";
1649                 set_reflog_action(&options);
1650
1651                 rerere_clear(the_repository, &merge_rr);
1652                 string_list_clear(&merge_rr, 1);
1653
1654                 if (read_basic_state(&options))
1655                         exit(1);
1656                 if (reset_head(&options.orig_head, "reset",
1657                                options.head_name, RESET_HEAD_HARD,
1658                                NULL, NULL) < 0)
1659                         die(_("could not move back to %s"),
1660                             oid_to_hex(&options.orig_head));
1661                 remove_branch_state(the_repository, 0);
1662                 ret = !!finish_rebase(&options);
1663                 goto cleanup;
1664         }
1665         case ACTION_QUIT: {
1666                 if (options.type == REBASE_INTERACTIVE) {
1667                         struct replay_opts replay = REPLAY_OPTS_INIT;
1668
1669                         replay.action = REPLAY_INTERACTIVE_REBASE;
1670                         ret = !!sequencer_remove_state(&replay);
1671                 } else {
1672                         strbuf_reset(&buf);
1673                         strbuf_addstr(&buf, options.state_dir);
1674                         ret = !!remove_dir_recursively(&buf, 0);
1675                         if (ret)
1676                                 error(_("could not remove '%s'"),
1677                                        options.state_dir);
1678                 }
1679                 goto cleanup;
1680         }
1681         case ACTION_EDIT_TODO:
1682                 options.action = "edit-todo";
1683                 options.dont_finish_rebase = 1;
1684                 goto run_rebase;
1685         case ACTION_SHOW_CURRENT_PATCH:
1686                 options.action = "show-current-patch";
1687                 options.dont_finish_rebase = 1;
1688                 goto run_rebase;
1689         case ACTION_NONE:
1690                 break;
1691         default:
1692                 BUG("action: %d", action);
1693         }
1694
1695         /* Make sure no rebase is in progress */
1696         if (in_progress) {
1697                 const char *last_slash = strrchr(options.state_dir, '/');
1698                 const char *state_dir_base =
1699                         last_slash ? last_slash + 1 : options.state_dir;
1700                 const char *cmd_live_rebase =
1701                         "git rebase (--continue | --abort | --skip)";
1702                 strbuf_reset(&buf);
1703                 strbuf_addf(&buf, "rm -fr \"%s\"", options.state_dir);
1704                 die(_("It seems that there is already a %s directory, and\n"
1705                       "I wonder if you are in the middle of another rebase.  "
1706                       "If that is the\n"
1707                       "case, please try\n\t%s\n"
1708                       "If that is not the case, please\n\t%s\n"
1709                       "and run me again.  I am stopping in case you still "
1710                       "have something\n"
1711                       "valuable there.\n"),
1712                     state_dir_base, cmd_live_rebase, buf.buf);
1713         }
1714
1715         for (i = 0; i < options.git_am_opts.argc; i++) {
1716                 const char *option = options.git_am_opts.argv[i], *p;
1717                 if (!strcmp(option, "--committer-date-is-author-date") ||
1718                     !strcmp(option, "--ignore-date") ||
1719                     !strcmp(option, "--whitespace=fix") ||
1720                     !strcmp(option, "--whitespace=strip"))
1721                         options.flags |= REBASE_FORCE;
1722                 else if (skip_prefix(option, "-C", &p)) {
1723                         while (*p)
1724                                 if (!isdigit(*(p++)))
1725                                         die(_("switch `C' expects a "
1726                                               "numerical value"));
1727                 } else if (skip_prefix(option, "--whitespace=", &p)) {
1728                         if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
1729                             strcmp(p, "error") && strcmp(p, "error-all"))
1730                                 die("Invalid whitespace option: '%s'", p);
1731                 }
1732         }
1733
1734         for (i = 0; i < exec.nr; i++)
1735                 if (check_exec_cmd(exec.items[i].string))
1736                         exit(1);
1737
1738         if (!(options.flags & REBASE_NO_QUIET))
1739                 argv_array_push(&options.git_am_opts, "-q");
1740
1741         if (options.keep_empty)
1742                 imply_interactive(&options, "--keep-empty");
1743
1744         if (gpg_sign) {
1745                 free(options.gpg_sign_opt);
1746                 options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
1747         }
1748
1749         if (exec.nr) {
1750                 int i;
1751
1752                 imply_interactive(&options, "--exec");
1753
1754                 strbuf_reset(&buf);
1755                 for (i = 0; i < exec.nr; i++)
1756                         strbuf_addf(&buf, "exec %s\n", exec.items[i].string);
1757                 options.cmd = xstrdup(buf.buf);
1758         }
1759
1760         if (rebase_merges) {
1761                 if (!*rebase_merges)
1762                         ; /* default mode; do nothing */
1763                 else if (!strcmp("rebase-cousins", rebase_merges))
1764                         options.rebase_cousins = 1;
1765                 else if (strcmp("no-rebase-cousins", rebase_merges))
1766                         die(_("Unknown mode: %s"), rebase_merges);
1767                 options.rebase_merges = 1;
1768                 imply_interactive(&options, "--rebase-merges");
1769         }
1770
1771         if (strategy_options.nr) {
1772                 int i;
1773
1774                 if (!options.strategy)
1775                         options.strategy = "recursive";
1776
1777                 strbuf_reset(&buf);
1778                 for (i = 0; i < strategy_options.nr; i++)
1779                         strbuf_addf(&buf, " --%s",
1780                                     strategy_options.items[i].string);
1781                 options.strategy_opts = xstrdup(buf.buf);
1782         }
1783
1784         if (options.strategy) {
1785                 options.strategy = xstrdup(options.strategy);
1786                 switch (options.type) {
1787                 case REBASE_AM:
1788                         die(_("--strategy requires --merge or --interactive"));
1789                 case REBASE_MERGE:
1790                 case REBASE_INTERACTIVE:
1791                 case REBASE_PRESERVE_MERGES:
1792                         /* compatible */
1793                         break;
1794                 case REBASE_UNSPECIFIED:
1795                         options.type = REBASE_MERGE;
1796                         break;
1797                 default:
1798                         BUG("unhandled rebase type (%d)", options.type);
1799                 }
1800         }
1801
1802         if (options.type == REBASE_MERGE)
1803                 imply_interactive(&options, "--merge");
1804
1805         if (options.root && !options.onto_name)
1806                 imply_interactive(&options, "--root without --onto");
1807
1808         if (isatty(2) && options.flags & REBASE_NO_QUIET)
1809                 strbuf_addstr(&options.git_format_patch_opt, " --progress");
1810
1811         switch (options.type) {
1812         case REBASE_MERGE:
1813         case REBASE_INTERACTIVE:
1814         case REBASE_PRESERVE_MERGES:
1815                 options.state_dir = merge_dir();
1816                 break;
1817         case REBASE_AM:
1818                 options.state_dir = apply_dir();
1819                 break;
1820         default:
1821                 /* the default rebase backend is `--am` */
1822                 options.type = REBASE_AM;
1823                 options.state_dir = apply_dir();
1824                 break;
1825         }
1826
1827         if (reschedule_failed_exec > 0 && !is_interactive(&options))
1828                 die(_("--reschedule-failed-exec requires "
1829                       "--exec or --interactive"));
1830         if (reschedule_failed_exec >= 0)
1831                 options.reschedule_failed_exec = reschedule_failed_exec;
1832
1833         if (options.git_am_opts.argc) {
1834                 /* all am options except -q are compatible only with --am */
1835                 for (i = options.git_am_opts.argc - 1; i >= 0; i--)
1836                         if (strcmp(options.git_am_opts.argv[i], "-q"))
1837                                 break;
1838
1839                 if (is_interactive(&options) && i >= 0)
1840                         die(_("cannot combine am options with either "
1841                               "interactive or merge options"));
1842         }
1843
1844         if (options.signoff) {
1845                 if (options.type == REBASE_PRESERVE_MERGES)
1846                         die("cannot combine '--signoff' with "
1847                             "'--preserve-merges'");
1848                 argv_array_push(&options.git_am_opts, "--signoff");
1849                 options.flags |= REBASE_FORCE;
1850         }
1851
1852         if (options.type == REBASE_PRESERVE_MERGES) {
1853                 /*
1854                  * Note: incompatibility with --signoff handled in signoff block above
1855                  * Note: incompatibility with --interactive is just a strong warning;
1856                  *       git-rebase.txt caveats with "unless you know what you are doing"
1857                  */
1858                 if (options.rebase_merges)
1859                         die(_("cannot combine '--preserve-merges' with "
1860                               "'--rebase-merges'"));
1861
1862                 if (options.reschedule_failed_exec)
1863                         die(_("error: cannot combine '--preserve-merges' with "
1864                               "'--reschedule-failed-exec'"));
1865         }
1866
1867         if (!options.root) {
1868                 if (argc < 1) {
1869                         struct branch *branch;
1870
1871                         branch = branch_get(NULL);
1872                         options.upstream_name = branch_get_upstream(branch,
1873                                                                     NULL);
1874                         if (!options.upstream_name)
1875                                 error_on_missing_default_upstream();
1876                         if (fork_point < 0)
1877                                 fork_point = 1;
1878                 } else {
1879                         options.upstream_name = argv[0];
1880                         argc--;
1881                         argv++;
1882                         if (!strcmp(options.upstream_name, "-"))
1883                                 options.upstream_name = "@{-1}";
1884                 }
1885                 options.upstream = peel_committish(options.upstream_name);
1886                 if (!options.upstream)
1887                         die(_("invalid upstream '%s'"), options.upstream_name);
1888                 options.upstream_arg = options.upstream_name;
1889         } else {
1890                 if (!options.onto_name) {
1891                         if (commit_tree("", 0, the_hash_algo->empty_tree, NULL,
1892                                         &squash_onto, NULL, NULL) < 0)
1893                                 die(_("Could not create new root commit"));
1894                         options.squash_onto = &squash_onto;
1895                         options.onto_name = squash_onto_name =
1896                                 xstrdup(oid_to_hex(&squash_onto));
1897                 } else
1898                         options.root_with_onto = 1;
1899
1900                 options.upstream_name = NULL;
1901                 options.upstream = NULL;
1902                 if (argc > 1)
1903                         usage_with_options(builtin_rebase_usage,
1904                                            builtin_rebase_options);
1905                 options.upstream_arg = "--root";
1906         }
1907
1908         /* Make sure the branch to rebase onto is valid. */
1909         if (keep_base) {
1910                 strbuf_reset(&buf);
1911                 strbuf_addstr(&buf, options.upstream_name);
1912                 strbuf_addstr(&buf, "...");
1913                 options.onto_name = xstrdup(buf.buf);
1914         } else if (!options.onto_name)
1915                 options.onto_name = options.upstream_name;
1916         if (strstr(options.onto_name, "...")) {
1917                 if (get_oid_mb(options.onto_name, &merge_base) < 0) {
1918                         if (keep_base)
1919                                 die(_("'%s': need exactly one merge base with branch"),
1920                                     options.upstream_name);
1921                         else
1922                                 die(_("'%s': need exactly one merge base"),
1923                                     options.onto_name);
1924                 }
1925                 options.onto = lookup_commit_or_die(&merge_base,
1926                                                     options.onto_name);
1927         } else {
1928                 options.onto = peel_committish(options.onto_name);
1929                 if (!options.onto)
1930                         die(_("Does not point to a valid commit '%s'"),
1931                                 options.onto_name);
1932         }
1933
1934         /*
1935          * If the branch to rebase is given, that is the branch we will rebase
1936          * branch_name -- branch/commit being rebased, or
1937          *                HEAD (already detached)
1938          * orig_head -- commit object name of tip of the branch before rebasing
1939          * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
1940          */
1941         if (argc == 1) {
1942                 /* Is it "rebase other branchname" or "rebase other commit"? */
1943                 branch_name = argv[0];
1944                 options.switch_to = argv[0];
1945
1946                 /* Is it a local branch? */
1947                 strbuf_reset(&buf);
1948                 strbuf_addf(&buf, "refs/heads/%s", branch_name);
1949                 if (!read_ref(buf.buf, &options.orig_head))
1950                         options.head_name = xstrdup(buf.buf);
1951                 /* If not is it a valid ref (branch or commit)? */
1952                 else if (!get_oid(branch_name, &options.orig_head))
1953                         options.head_name = NULL;
1954                 else
1955                         die(_("fatal: no such branch/commit '%s'"),
1956                             branch_name);
1957         } else if (argc == 0) {
1958                 /* Do not need to switch branches, we are already on it. */
1959                 options.head_name =
1960                         xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
1961                                          &flags));
1962                 if (!options.head_name)
1963                         die(_("No such ref: %s"), "HEAD");
1964                 if (flags & REF_ISSYMREF) {
1965                         if (!skip_prefix(options.head_name,
1966                                          "refs/heads/", &branch_name))
1967                                 branch_name = options.head_name;
1968
1969                 } else {
1970                         FREE_AND_NULL(options.head_name);
1971                         branch_name = "HEAD";
1972                 }
1973                 if (get_oid("HEAD", &options.orig_head))
1974                         die(_("Could not resolve HEAD to a revision"));
1975         } else
1976                 BUG("unexpected number of arguments left to parse");
1977
1978         if (fork_point > 0) {
1979                 struct commit *head =
1980                         lookup_commit_reference(the_repository,
1981                                                 &options.orig_head);
1982                 options.restrict_revision =
1983                         get_fork_point(options.upstream_name, head);
1984         }
1985
1986         if (repo_read_index(the_repository) < 0)
1987                 die(_("could not read index"));
1988
1989         if (options.autostash) {
1990                 struct lock_file lock_file = LOCK_INIT;
1991                 int fd;
1992
1993                 fd = hold_locked_index(&lock_file, 0);
1994                 refresh_cache(REFRESH_QUIET);
1995                 if (0 <= fd)
1996                         repo_update_index_if_able(the_repository, &lock_file);
1997                 rollback_lock_file(&lock_file);
1998
1999                 if (has_unstaged_changes(the_repository, 1) ||
2000                     has_uncommitted_changes(the_repository, 1)) {
2001                         const char *autostash =
2002                                 state_dir_path("autostash", &options);
2003                         struct child_process stash = CHILD_PROCESS_INIT;
2004                         struct object_id oid;
2005
2006                         argv_array_pushl(&stash.args,
2007                                          "stash", "create", "autostash", NULL);
2008                         stash.git_cmd = 1;
2009                         stash.no_stdin = 1;
2010                         strbuf_reset(&buf);
2011                         if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
2012                                 die(_("Cannot autostash"));
2013                         strbuf_trim_trailing_newline(&buf);
2014                         if (get_oid(buf.buf, &oid))
2015                                 die(_("Unexpected stash response: '%s'"),
2016                                     buf.buf);
2017                         strbuf_reset(&buf);
2018                         strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
2019
2020                         if (safe_create_leading_directories_const(autostash))
2021                                 die(_("Could not create directory for '%s'"),
2022                                     options.state_dir);
2023                         write_file(autostash, "%s", oid_to_hex(&oid));
2024                         printf(_("Created autostash: %s\n"), buf.buf);
2025                         if (reset_head(NULL, "reset --hard",
2026                                        NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
2027                                 die(_("could not reset --hard"));
2028
2029                         if (discard_index(the_repository->index) < 0 ||
2030                                 repo_read_index(the_repository) < 0)
2031                                 die(_("could not read index"));
2032                 }
2033         }
2034
2035         if (require_clean_work_tree(the_repository, "rebase",
2036                                     _("Please commit or stash them."), 1, 1)) {
2037                 ret = 1;
2038                 goto cleanup;
2039         }
2040
2041         /*
2042          * Now we are rebasing commits upstream..orig_head (or with --root,
2043          * everything leading up to orig_head) on top of onto.
2044          */
2045
2046         /*
2047          * Check if we are already based on onto with linear history,
2048          * in which case we could fast-forward without replacing the commits
2049          * with new commits recreated by replaying their changes. This
2050          * optimization must not be done if this is an interactive rebase.
2051          */
2052         if (can_fast_forward(options.onto, options.upstream, options.restrict_revision,
2053                     &options.orig_head, &merge_base) &&
2054             !is_interactive(&options)) {
2055                 int flag;
2056
2057                 if (!(options.flags & REBASE_FORCE)) {
2058                         /* Lazily switch to the target branch if needed... */
2059                         if (options.switch_to) {
2060                                 struct object_id oid;
2061
2062                                 if (get_oid(options.switch_to, &oid) < 0) {
2063                                         ret = !!error(_("could not parse '%s'"),
2064                                                       options.switch_to);
2065                                         goto cleanup;
2066                                 }
2067
2068                                 strbuf_reset(&buf);
2069                                 strbuf_addf(&buf, "%s: checkout %s",
2070                                             getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
2071                                             options.switch_to);
2072                                 if (reset_head(&oid, "checkout",
2073                                                options.head_name,
2074                                                RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
2075                                                NULL, buf.buf) < 0) {
2076                                         ret = !!error(_("could not switch to "
2077                                                         "%s"),
2078                                                       options.switch_to);
2079                                         goto cleanup;
2080                                 }
2081                         }
2082
2083                         if (!(options.flags & REBASE_NO_QUIET))
2084                                 ; /* be quiet */
2085                         else if (!strcmp(branch_name, "HEAD") &&
2086                                  resolve_ref_unsafe("HEAD", 0, NULL, &flag))
2087                                 puts(_("HEAD is up to date."));
2088                         else
2089                                 printf(_("Current branch %s is up to date.\n"),
2090                                        branch_name);
2091                         ret = !!finish_rebase(&options);
2092                         goto cleanup;
2093                 } else if (!(options.flags & REBASE_NO_QUIET))
2094                         ; /* be quiet */
2095                 else if (!strcmp(branch_name, "HEAD") &&
2096                          resolve_ref_unsafe("HEAD", 0, NULL, &flag))
2097                         puts(_("HEAD is up to date, rebase forced."));
2098                 else
2099                         printf(_("Current branch %s is up to date, rebase "
2100                                  "forced.\n"), branch_name);
2101         }
2102
2103         /* If a hook exists, give it a chance to interrupt*/
2104         if (!ok_to_skip_pre_rebase &&
2105             run_hook_le(NULL, "pre-rebase", options.upstream_arg,
2106                         argc ? argv[0] : NULL, NULL))
2107                 die(_("The pre-rebase hook refused to rebase."));
2108
2109         if (options.flags & REBASE_DIFFSTAT) {
2110                 struct diff_options opts;
2111
2112                 if (options.flags & REBASE_VERBOSE) {
2113                         if (is_null_oid(&merge_base))
2114                                 printf(_("Changes to %s:\n"),
2115                                        oid_to_hex(&options.onto->object.oid));
2116                         else
2117                                 printf(_("Changes from %s to %s:\n"),
2118                                        oid_to_hex(&merge_base),
2119                                        oid_to_hex(&options.onto->object.oid));
2120                 }
2121
2122                 /* We want color (if set), but no pager */
2123                 diff_setup(&opts);
2124                 opts.stat_width = -1; /* use full terminal width */
2125                 opts.stat_graph_width = -1; /* respect statGraphWidth config */
2126                 opts.output_format |=
2127                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
2128                 opts.detect_rename = DIFF_DETECT_RENAME;
2129                 diff_setup_done(&opts);
2130                 diff_tree_oid(is_null_oid(&merge_base) ?
2131                               the_hash_algo->empty_tree : &merge_base,
2132                               &options.onto->object.oid, "", &opts);
2133                 diffcore_std(&opts);
2134                 diff_flush(&opts);
2135         }
2136
2137         if (is_interactive(&options))
2138                 goto run_rebase;
2139
2140         /* Detach HEAD and reset the tree */
2141         if (options.flags & REBASE_NO_QUIET)
2142                 printf(_("First, rewinding head to replay your work on top of "
2143                          "it...\n"));
2144
2145         strbuf_addf(&msg, "%s: checkout %s",
2146                     getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
2147         if (reset_head(&options.onto->object.oid, "checkout", NULL,
2148                        RESET_HEAD_DETACH | RESET_ORIG_HEAD |
2149                        RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
2150                        NULL, msg.buf))
2151                 die(_("Could not detach HEAD"));
2152         strbuf_release(&msg);
2153
2154         /*
2155          * If the onto is a proper descendant of the tip of the branch, then
2156          * we just fast-forwarded.
2157          */
2158         strbuf_reset(&msg);
2159         if (oideq(&merge_base, &options.orig_head)) {
2160                 printf(_("Fast-forwarded %s to %s.\n"),
2161                         branch_name, options.onto_name);
2162                 strbuf_addf(&msg, "rebase finished: %s onto %s",
2163                         options.head_name ? options.head_name : "detached HEAD",
2164                         oid_to_hex(&options.onto->object.oid));
2165                 reset_head(NULL, "Fast-forwarded", options.head_name,
2166                            RESET_HEAD_REFS_ONLY, "HEAD", msg.buf);
2167                 strbuf_release(&msg);
2168                 ret = !!finish_rebase(&options);
2169                 goto cleanup;
2170         }
2171
2172         strbuf_addf(&revisions, "%s..%s",
2173                     options.root ? oid_to_hex(&options.onto->object.oid) :
2174                     (options.restrict_revision ?
2175                      oid_to_hex(&options.restrict_revision->object.oid) :
2176                      oid_to_hex(&options.upstream->object.oid)),
2177                     oid_to_hex(&options.orig_head));
2178
2179         options.revisions = revisions.buf;
2180
2181 run_rebase:
2182         ret = !!run_specific_rebase(&options, action);
2183
2184 cleanup:
2185         strbuf_release(&buf);
2186         strbuf_release(&revisions);
2187         free(options.head_name);
2188         free(options.gpg_sign_opt);
2189         free(options.cmd);
2190         free(squash_onto_name);
2191         return ret;
2192 }