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