Merge branch 'sp/maint-smart-http-sans-100-continue'
[git] / builtin / revert.c
1 #include "cache.h"
2 #include "builtin.h"
3 #include "object.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "wt-status.h"
7 #include "run-command.h"
8 #include "exec_cmd.h"
9 #include "utf8.h"
10 #include "parse-options.h"
11 #include "cache-tree.h"
12 #include "diff.h"
13 #include "revision.h"
14 #include "rerere.h"
15 #include "merge-recursive.h"
16 #include "refs.h"
17
18 /*
19  * This implements the builtins revert and cherry-pick.
20  *
21  * Copyright (c) 2007 Johannes E. Schindelin
22  *
23  * Based on git-revert.sh, which is
24  *
25  * Copyright (c) 2005 Linus Torvalds
26  * Copyright (c) 2005 Junio C Hamano
27  */
28
29 static const char * const revert_usage[] = {
30         "git revert [options] <commit-ish>",
31         NULL
32 };
33
34 static const char * const cherry_pick_usage[] = {
35         "git cherry-pick [options] <commit-ish>",
36         NULL
37 };
38
39 static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
40 static enum { REVERT, CHERRY_PICK } action;
41 static struct commit *commit;
42 static int commit_argc;
43 static const char **commit_argv;
44 static int allow_rerere_auto;
45
46 static const char *me;
47
48 /* Merge strategy. */
49 static const char *strategy;
50 static const char **xopts;
51 static size_t xopts_nr, xopts_alloc;
52
53 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
54
55 static char *get_encoding(const char *message);
56
57 static const char * const *revert_or_cherry_pick_usage(void)
58 {
59         return action == REVERT ? revert_usage : cherry_pick_usage;
60 }
61
62 static int option_parse_x(const struct option *opt,
63                           const char *arg, int unset)
64 {
65         if (unset)
66                 return 0;
67
68         ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
69         xopts[xopts_nr++] = xstrdup(arg);
70         return 0;
71 }
72
73 static void parse_args(int argc, const char **argv)
74 {
75         const char * const * usage_str = revert_or_cherry_pick_usage();
76         int noop;
77         struct option options[] = {
78                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
79                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
80                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
81                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
82                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
83                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
84                 OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
85                 OPT_CALLBACK('X', "strategy-option", &xopts, "option",
86                         "option for merge strategy", option_parse_x),
87                 OPT_END(),
88                 OPT_END(),
89                 OPT_END(),
90         };
91
92         if (action == CHERRY_PICK) {
93                 struct option cp_extra[] = {
94                         OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
95                         OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
96                         OPT_END(),
97                 };
98                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
99                         die("program error");
100         }
101
102         commit_argc = parse_options(argc, argv, NULL, options, usage_str,
103                                     PARSE_OPT_KEEP_ARGV0 |
104                                     PARSE_OPT_KEEP_UNKNOWN);
105         if (commit_argc < 2)
106                 usage_with_options(usage_str, options);
107
108         commit_argv = argv;
109 }
110
111 struct commit_message {
112         char *parent_label;
113         const char *label;
114         const char *subject;
115         char *reencoded_message;
116         const char *message;
117 };
118
119 static int get_message(const char *raw_message, struct commit_message *out)
120 {
121         const char *encoding;
122         const char *abbrev, *subject;
123         int abbrev_len, subject_len;
124         char *q;
125
126         if (!raw_message)
127                 return -1;
128         encoding = get_encoding(raw_message);
129         if (!encoding)
130                 encoding = "UTF-8";
131         if (!git_commit_encoding)
132                 git_commit_encoding = "UTF-8";
133
134         out->reencoded_message = NULL;
135         out->message = raw_message;
136         if (strcmp(encoding, git_commit_encoding))
137                 out->reencoded_message = reencode_string(raw_message,
138                                         git_commit_encoding, encoding);
139         if (out->reencoded_message)
140                 out->message = out->reencoded_message;
141
142         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
143         abbrev_len = strlen(abbrev);
144
145         subject_len = find_commit_subject(out->message, &subject);
146
147         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
148                               strlen("... ") + subject_len + 1);
149         q = out->parent_label;
150         q = mempcpy(q, "parent of ", strlen("parent of "));
151         out->label = q;
152         q = mempcpy(q, abbrev, abbrev_len);
153         q = mempcpy(q, "... ", strlen("... "));
154         out->subject = q;
155         q = mempcpy(q, subject, subject_len);
156         *q = '\0';
157         return 0;
158 }
159
160 static void free_message(struct commit_message *msg)
161 {
162         free(msg->parent_label);
163         free(msg->reencoded_message);
164 }
165
166 static char *get_encoding(const char *message)
167 {
168         const char *p = message, *eol;
169
170         if (!p)
171                 die ("Could not read commit message of %s",
172                                 sha1_to_hex(commit->object.sha1));
173         while (*p && *p != '\n') {
174                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
175                         ; /* do nothing */
176                 if (!prefixcmp(p, "encoding ")) {
177                         char *result = xmalloc(eol - 8 - p);
178                         strlcpy(result, p + 9, eol - 8 - p);
179                         return result;
180                 }
181                 p = eol;
182                 if (*p == '\n')
183                         p++;
184         }
185         return NULL;
186 }
187
188 static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
189 {
190         const char *p = message;
191         while (*p && (*p != '\n' || p[1] != '\n'))
192                 p++;
193
194         if (!*p)
195                 strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
196
197         p += 2;
198         strbuf_addstr(msgbuf, p);
199 }
200
201 static void set_author_ident_env(const char *message)
202 {
203         const char *p = message;
204         if (!p)
205                 die ("Could not read commit message of %s",
206                                 sha1_to_hex(commit->object.sha1));
207         while (*p && *p != '\n') {
208                 const char *eol;
209
210                 for (eol = p; *eol && *eol != '\n'; eol++)
211                         ; /* do nothing */
212                 if (!prefixcmp(p, "author ")) {
213                         char *line, *pend, *email, *timestamp;
214
215                         p += 7;
216                         line = xmemdupz(p, eol - p);
217                         email = strchr(line, '<');
218                         if (!email)
219                                 die ("Could not extract author email from %s",
220                                         sha1_to_hex(commit->object.sha1));
221                         if (email == line)
222                                 pend = line;
223                         else
224                                 for (pend = email; pend != line + 1 &&
225                                                 isspace(pend[-1]); pend--);
226                                         ; /* do nothing */
227                         *pend = '\0';
228                         email++;
229                         timestamp = strchr(email, '>');
230                         if (!timestamp)
231                                 die ("Could not extract author time from %s",
232                                         sha1_to_hex(commit->object.sha1));
233                         *timestamp = '\0';
234                         for (timestamp++; *timestamp && isspace(*timestamp);
235                                         timestamp++)
236                                 ; /* do nothing */
237                         setenv("GIT_AUTHOR_NAME", line, 1);
238                         setenv("GIT_AUTHOR_EMAIL", email, 1);
239                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
240                         free(line);
241                         return;
242                 }
243                 p = eol;
244                 if (*p == '\n')
245                         p++;
246         }
247         die ("No author information found in %s",
248                         sha1_to_hex(commit->object.sha1));
249 }
250
251 static void advise(const char *advice, ...)
252 {
253         va_list params;
254
255         va_start(params, advice);
256         vreportf("hint: ", advice, params);
257         va_end(params);
258 }
259
260 static void print_advice(void)
261 {
262         char *msg = getenv("GIT_CHERRY_PICK_HELP");
263
264         if (msg) {
265                 fprintf(stderr, "%s\n", msg);
266                 return;
267         }
268
269         advise("after resolving the conflicts, mark the corrected paths");
270         advise("with 'git add <paths>' or 'git rm <paths>'");
271
272         if (action == CHERRY_PICK)
273                 advise("and commit the result with 'git commit -c %s'",
274                        find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
275 }
276
277 static void write_message(struct strbuf *msgbuf, const char *filename)
278 {
279         static struct lock_file msg_file;
280
281         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
282                                                LOCK_DIE_ON_ERROR);
283         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
284                 die_errno("Could not write to %s.", filename);
285         strbuf_release(msgbuf);
286         if (commit_lock_file(&msg_file) < 0)
287                 die("Error wrapping up %s", filename);
288 }
289
290 static struct tree *empty_tree(void)
291 {
292         struct tree *tree = xcalloc(1, sizeof(struct tree));
293
294         tree->object.parsed = 1;
295         tree->object.type = OBJ_TREE;
296         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
297         return tree;
298 }
299
300 static NORETURN void die_dirty_index(const char *me)
301 {
302         if (read_cache_unmerged()) {
303                 die_resolve_conflict(me);
304         } else {
305                 if (advice_commit_before_merge)
306                         die("Your local changes would be overwritten by %s.\n"
307                             "Please, commit your changes or stash them to proceed.", me);
308                 else
309                         die("Your local changes would be overwritten by %s.\n", me);
310         }
311 }
312
313 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
314 {
315         struct ref_lock *ref_lock;
316
317         read_cache();
318         if (checkout_fast_forward(from, to))
319                 exit(1); /* the callee should have complained already */
320         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
321         return write_ref_sha1(ref_lock, to, "cherry-pick");
322 }
323
324 static int do_recursive_merge(struct commit *base, struct commit *next,
325                               const char *base_label, const char *next_label,
326                               unsigned char *head, struct strbuf *msgbuf)
327 {
328         struct merge_options o;
329         struct tree *result, *next_tree, *base_tree, *head_tree;
330         int clean, index_fd;
331         const char **xopt;
332         static struct lock_file index_lock;
333
334         index_fd = hold_locked_index(&index_lock, 1);
335
336         read_cache();
337
338         init_merge_options(&o);
339         o.ancestor = base ? base_label : "(empty tree)";
340         o.branch1 = "HEAD";
341         o.branch2 = next ? next_label : "(empty tree)";
342
343         head_tree = parse_tree_indirect(head);
344         next_tree = next ? next->tree : empty_tree();
345         base_tree = base ? base->tree : empty_tree();
346
347         for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
348                 parse_merge_opt(&o, *xopt);
349
350         clean = merge_trees(&o,
351                             head_tree,
352                             next_tree, base_tree, &result);
353
354         if (active_cache_changed &&
355             (write_cache(index_fd, active_cache, active_nr) ||
356              commit_locked_index(&index_lock)))
357                 die("%s: Unable to write new index file", me);
358         rollback_lock_file(&index_lock);
359
360         if (!clean) {
361                 int i;
362                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
363                 for (i = 0; i < active_nr;) {
364                         struct cache_entry *ce = active_cache[i++];
365                         if (ce_stage(ce)) {
366                                 strbuf_addch(msgbuf, '\t');
367                                 strbuf_addstr(msgbuf, ce->name);
368                                 strbuf_addch(msgbuf, '\n');
369                                 while (i < active_nr && !strcmp(ce->name,
370                                                 active_cache[i]->name))
371                                         i++;
372                         }
373                 }
374         }
375
376         return !clean;
377 }
378
379 /*
380  * If we are cherry-pick, and if the merge did not result in
381  * hand-editing, we will hit this commit and inherit the original
382  * author date and name.
383  * If we are revert, or if our cherry-pick results in a hand merge,
384  * we had better say that the current user is responsible for that.
385  */
386 static int run_git_commit(const char *defmsg)
387 {
388         /* 6 is max possible length of our args array including NULL */
389         const char *args[6];
390         int i = 0;
391
392         args[i++] = "commit";
393         args[i++] = "-n";
394         if (signoff)
395                 args[i++] = "-s";
396         if (!edit) {
397                 args[i++] = "-F";
398                 args[i++] = defmsg;
399         }
400         args[i] = NULL;
401
402         return run_command_v_opt(args, RUN_GIT_CMD);
403 }
404
405 static int do_pick_commit(void)
406 {
407         unsigned char head[20];
408         struct commit *base, *next, *parent;
409         const char *base_label, *next_label;
410         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
411         char *defmsg = NULL;
412         struct strbuf msgbuf = STRBUF_INIT;
413         int res;
414
415         if (no_commit) {
416                 /*
417                  * We do not intend to commit immediately.  We just want to
418                  * merge the differences in, so let's compute the tree
419                  * that represents the "current" state for merge-recursive
420                  * to work on.
421                  */
422                 if (write_cache_as_tree(head, 0, NULL))
423                         die ("Your index file is unmerged.");
424         } else {
425                 if (get_sha1("HEAD", head))
426                         die ("You do not have a valid HEAD");
427                 if (index_differs_from("HEAD", 0))
428                         die_dirty_index(me);
429         }
430         discard_cache();
431
432         if (!commit->parents) {
433                 if (action == REVERT)
434                         die ("Cannot revert a root commit");
435                 parent = NULL;
436         }
437         else if (commit->parents->next) {
438                 /* Reverting or cherry-picking a merge commit */
439                 int cnt;
440                 struct commit_list *p;
441
442                 if (!mainline)
443                         die("Commit %s is a merge but no -m option was given.",
444                             sha1_to_hex(commit->object.sha1));
445
446                 for (cnt = 1, p = commit->parents;
447                      cnt != mainline && p;
448                      cnt++)
449                         p = p->next;
450                 if (cnt != mainline || !p)
451                         die("Commit %s does not have parent %d",
452                             sha1_to_hex(commit->object.sha1), mainline);
453                 parent = p->item;
454         } else if (0 < mainline)
455                 die("Mainline was specified but commit %s is not a merge.",
456                     sha1_to_hex(commit->object.sha1));
457         else
458                 parent = commit->parents->item;
459
460         if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
461                 return fast_forward_to(commit->object.sha1, head);
462
463         if (parent && parse_commit(parent) < 0)
464                 die("%s: cannot parse parent commit %s",
465                     me, sha1_to_hex(parent->object.sha1));
466
467         if (get_message(commit->buffer, &msg) != 0)
468                 die("Cannot get commit message for %s",
469                                 sha1_to_hex(commit->object.sha1));
470
471         /*
472          * "commit" is an existing commit.  We would want to apply
473          * the difference it introduces since its first parent "prev"
474          * on top of the current HEAD if we are cherry-pick.  Or the
475          * reverse of it if we are revert.
476          */
477
478         defmsg = git_pathdup("MERGE_MSG");
479
480         if (action == REVERT) {
481                 base = commit;
482                 base_label = msg.label;
483                 next = parent;
484                 next_label = msg.parent_label;
485                 strbuf_addstr(&msgbuf, "Revert \"");
486                 strbuf_addstr(&msgbuf, msg.subject);
487                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
488                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
489
490                 if (commit->parents->next) {
491                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
492                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
493                 }
494                 strbuf_addstr(&msgbuf, ".\n");
495         } else {
496                 base = parent;
497                 base_label = msg.parent_label;
498                 next = commit;
499                 next_label = msg.label;
500                 set_author_ident_env(msg.message);
501                 add_message_to_msg(&msgbuf, msg.message);
502                 if (no_replay) {
503                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
504                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
505                         strbuf_addstr(&msgbuf, ")\n");
506                 }
507         }
508
509         if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
510                 res = do_recursive_merge(base, next, base_label, next_label,
511                                          head, &msgbuf);
512                 write_message(&msgbuf, defmsg);
513         } else {
514                 struct commit_list *common = NULL;
515                 struct commit_list *remotes = NULL;
516
517                 write_message(&msgbuf, defmsg);
518
519                 commit_list_insert(base, &common);
520                 commit_list_insert(next, &remotes);
521                 res = try_merge_command(strategy, xopts_nr, xopts, common,
522                                         sha1_to_hex(head), remotes);
523                 free_commit_list(common);
524                 free_commit_list(remotes);
525         }
526
527         if (res) {
528                 error("could not %s %s... %s",
529                       action == REVERT ? "revert" : "apply",
530                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
531                       msg.subject);
532                 print_advice();
533                 rerere(allow_rerere_auto);
534         } else {
535                 if (!no_commit)
536                         res = run_git_commit(defmsg);
537         }
538
539         free_message(&msg);
540         free(defmsg);
541
542         return res;
543 }
544
545 static void prepare_revs(struct rev_info *revs)
546 {
547         int argc;
548
549         init_revisions(revs, NULL);
550         revs->no_walk = 1;
551         if (action != REVERT)
552                 revs->reverse = 1;
553
554         argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
555         if (argc > 1)
556                 usage(*revert_or_cherry_pick_usage());
557
558         if (prepare_revision_walk(revs))
559                 die("revision walk setup failed");
560
561         if (!revs->commits)
562                 die("empty commit set passed");
563 }
564
565 static void read_and_refresh_cache(const char *me)
566 {
567         static struct lock_file index_lock;
568         int index_fd = hold_locked_index(&index_lock, 0);
569         if (read_index_preload(&the_index, NULL) < 0)
570                 die("git %s: failed to read the index", me);
571         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
572         if (the_index.cache_changed) {
573                 if (write_index(&the_index, index_fd) ||
574                     commit_locked_index(&index_lock))
575                         die("git %s: failed to refresh the index", me);
576         }
577         rollback_lock_file(&index_lock);
578 }
579
580 static int revert_or_cherry_pick(int argc, const char **argv)
581 {
582         struct rev_info revs;
583
584         git_config(git_default_config, NULL);
585         me = action == REVERT ? "revert" : "cherry-pick";
586         setenv(GIT_REFLOG_ACTION, me, 0);
587         parse_args(argc, argv);
588
589         if (allow_ff) {
590                 if (signoff)
591                         die("cherry-pick --ff cannot be used with --signoff");
592                 if (no_commit)
593                         die("cherry-pick --ff cannot be used with --no-commit");
594                 if (no_replay)
595                         die("cherry-pick --ff cannot be used with -x");
596                 if (edit)
597                         die("cherry-pick --ff cannot be used with --edit");
598         }
599
600         read_and_refresh_cache(me);
601
602         prepare_revs(&revs);
603
604         while ((commit = get_revision(&revs))) {
605                 int res = do_pick_commit();
606                 if (res)
607                         return res;
608         }
609
610         return 0;
611 }
612
613 int cmd_revert(int argc, const char **argv, const char *prefix)
614 {
615         if (isatty(0))
616                 edit = 1;
617         action = REVERT;
618         return revert_or_cherry_pick(argc, argv);
619 }
620
621 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
622 {
623         action = CHERRY_PICK;
624         return revert_or_cherry_pick(argc, argv);
625 }