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