Merge branch 'il/maint-xmallocz'
[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
17 /*
18  * This implements the builtins revert and cherry-pick.
19  *
20  * Copyright (c) 2007 Johannes E. Schindelin
21  *
22  * Based on git-revert.sh, which is
23  *
24  * Copyright (c) 2005 Linus Torvalds
25  * Copyright (c) 2005 Junio C Hamano
26  */
27
28 static const char * const revert_usage[] = {
29         "git revert [options] <commit-ish>",
30         NULL
31 };
32
33 static const char * const cherry_pick_usage[] = {
34         "git cherry-pick [options] <commit-ish>",
35         NULL
36 };
37
38 static int edit, no_replay, no_commit, mainline, signoff;
39 static enum { REVERT, CHERRY_PICK } action;
40 static struct commit *commit;
41 static int allow_rerere_auto;
42
43 static const char *me;
44
45 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
46
47 static void parse_args(int argc, const char **argv)
48 {
49         const char * const * usage_str =
50                 action == REVERT ?  revert_usage : cherry_pick_usage;
51         unsigned char sha1[20];
52         const char *arg;
53         int noop;
54         struct option options[] = {
55                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
56                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
57                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
58                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
59                 OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
60                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
61                 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
62                 OPT_END(),
63         };
64
65         if (parse_options(argc, argv, NULL, options, usage_str, 0) != 1)
66                 usage_with_options(usage_str, options);
67         arg = argv[0];
68
69         if (get_sha1(arg, sha1))
70                 die ("Cannot find '%s'", arg);
71         commit = (struct commit *)parse_object(sha1);
72         if (!commit)
73                 die ("Could not find %s", sha1_to_hex(sha1));
74         if (commit->object.type == OBJ_TAG) {
75                 commit = (struct commit *)
76                         deref_tag((struct object *)commit, arg, strlen(arg));
77         }
78         if (commit->object.type != OBJ_COMMIT)
79                 die ("'%s' does not point to a commit", arg);
80 }
81
82 static char *get_oneline(const char *message)
83 {
84         char *result;
85         const char *p = message, *abbrev, *eol;
86         int abbrev_len, oneline_len;
87
88         if (!p)
89                 die ("Could not read commit message of %s",
90                                 sha1_to_hex(commit->object.sha1));
91         while (*p && (*p != '\n' || p[1] != '\n'))
92                 p++;
93
94         if (*p) {
95                 p += 2;
96                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
97                         ; /* do nothing */
98         } else
99                 eol = p;
100         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
101         abbrev_len = strlen(abbrev);
102         oneline_len = eol - p;
103         result = xmalloc(abbrev_len + 5 + oneline_len);
104         memcpy(result, abbrev, abbrev_len);
105         memcpy(result + abbrev_len, "... ", 4);
106         memcpy(result + abbrev_len + 4, p, oneline_len);
107         result[abbrev_len + 4 + oneline_len] = '\0';
108         return result;
109 }
110
111 static char *get_encoding(const char *message)
112 {
113         const char *p = message, *eol;
114
115         if (!p)
116                 die ("Could not read commit message of %s",
117                                 sha1_to_hex(commit->object.sha1));
118         while (*p && *p != '\n') {
119                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
120                         ; /* do nothing */
121                 if (!prefixcmp(p, "encoding ")) {
122                         char *result = xmalloc(eol - 8 - p);
123                         strlcpy(result, p + 9, eol - 8 - p);
124                         return result;
125                 }
126                 p = eol;
127                 if (*p == '\n')
128                         p++;
129         }
130         return NULL;
131 }
132
133 static struct lock_file msg_file;
134 static int msg_fd;
135
136 static void add_to_msg(const char *string)
137 {
138         int len = strlen(string);
139         if (write_in_full(msg_fd, string, len) < 0)
140                 die_errno ("Could not write to MERGE_MSG");
141 }
142
143 static void add_message_to_msg(const char *message)
144 {
145         const char *p = message;
146         while (*p && (*p != '\n' || p[1] != '\n'))
147                 p++;
148
149         if (!*p)
150                 add_to_msg(sha1_to_hex(commit->object.sha1));
151
152         p += 2;
153         add_to_msg(p);
154         return;
155 }
156
157 static void set_author_ident_env(const char *message)
158 {
159         const char *p = message;
160         if (!p)
161                 die ("Could not read commit message of %s",
162                                 sha1_to_hex(commit->object.sha1));
163         while (*p && *p != '\n') {
164                 const char *eol;
165
166                 for (eol = p; *eol && *eol != '\n'; eol++)
167                         ; /* do nothing */
168                 if (!prefixcmp(p, "author ")) {
169                         char *line, *pend, *email, *timestamp;
170
171                         p += 7;
172                         line = xmemdupz(p, eol - p);
173                         email = strchr(line, '<');
174                         if (!email)
175                                 die ("Could not extract author email from %s",
176                                         sha1_to_hex(commit->object.sha1));
177                         if (email == line)
178                                 pend = line;
179                         else
180                                 for (pend = email; pend != line + 1 &&
181                                                 isspace(pend[-1]); pend--);
182                                         ; /* do nothing */
183                         *pend = '\0';
184                         email++;
185                         timestamp = strchr(email, '>');
186                         if (!timestamp)
187                                 die ("Could not extract author time from %s",
188                                         sha1_to_hex(commit->object.sha1));
189                         *timestamp = '\0';
190                         for (timestamp++; *timestamp && isspace(*timestamp);
191                                         timestamp++)
192                                 ; /* do nothing */
193                         setenv("GIT_AUTHOR_NAME", line, 1);
194                         setenv("GIT_AUTHOR_EMAIL", email, 1);
195                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
196                         free(line);
197                         return;
198                 }
199                 p = eol;
200                 if (*p == '\n')
201                         p++;
202         }
203         die ("No author information found in %s",
204                         sha1_to_hex(commit->object.sha1));
205 }
206
207 static char *help_msg(const unsigned char *sha1)
208 {
209         static char helpbuf[1024];
210         char *msg = getenv("GIT_CHERRY_PICK_HELP");
211
212         if (msg)
213                 return msg;
214
215         strcpy(helpbuf, "  After resolving the conflicts,\n"
216                "mark the corrected paths with 'git add <paths>' "
217                "or 'git rm <paths>' and commit the result.");
218
219         if (action == CHERRY_PICK) {
220                 sprintf(helpbuf + strlen(helpbuf),
221                         "\nWhen commiting, use the option "
222                         "'-c %s' to retain authorship and message.",
223                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
224         }
225         return helpbuf;
226 }
227
228 static struct tree *empty_tree(void)
229 {
230         struct tree *tree = xcalloc(1, sizeof(struct tree));
231
232         tree->object.parsed = 1;
233         tree->object.type = OBJ_TREE;
234         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
235         return tree;
236 }
237
238 static NORETURN void die_dirty_index(const char *me)
239 {
240         if (read_cache_unmerged()) {
241                 die_resolve_conflict(me);
242         } else {
243                 if (advice_commit_before_merge)
244                         die("Your local changes would be overwritten by %s.\n"
245                             "Please, commit your changes or stash them to proceed.", me);
246                 else
247                         die("Your local changes would be overwritten by %s.\n", me);
248         }
249 }
250
251 static int revert_or_cherry_pick(int argc, const char **argv)
252 {
253         unsigned char head[20];
254         struct commit *base, *next, *parent;
255         int i, index_fd, clean;
256         char *oneline, *reencoded_message = NULL;
257         const char *message, *encoding;
258         char *defmsg = git_pathdup("MERGE_MSG");
259         struct merge_options o;
260         struct tree *result, *next_tree, *base_tree, *head_tree;
261         static struct lock_file index_lock;
262
263         git_config(git_default_config, NULL);
264         me = action == REVERT ? "revert" : "cherry-pick";
265         setenv(GIT_REFLOG_ACTION, me, 0);
266         parse_args(argc, argv);
267
268         /* this is copied from the shell script, but it's never triggered... */
269         if (action == REVERT && !no_replay)
270                 die("revert is incompatible with replay");
271
272         if (read_cache() < 0)
273                 die("git %s: failed to read the index", me);
274         if (no_commit) {
275                 /*
276                  * We do not intend to commit immediately.  We just want to
277                  * merge the differences in, so let's compute the tree
278                  * that represents the "current" state for merge-recursive
279                  * to work on.
280                  */
281                 if (write_cache_as_tree(head, 0, NULL))
282                         die ("Your index file is unmerged.");
283         } else {
284                 if (get_sha1("HEAD", head))
285                         die ("You do not have a valid HEAD");
286                 if (index_differs_from("HEAD", 0))
287                         die_dirty_index(me);
288         }
289         discard_cache();
290
291         index_fd = hold_locked_index(&index_lock, 1);
292
293         if (!commit->parents) {
294                 if (action == REVERT)
295                         die ("Cannot revert a root commit");
296                 parent = NULL;
297         }
298         else if (commit->parents->next) {
299                 /* Reverting or cherry-picking a merge commit */
300                 int cnt;
301                 struct commit_list *p;
302
303                 if (!mainline)
304                         die("Commit %s is a merge but no -m option was given.",
305                             sha1_to_hex(commit->object.sha1));
306
307                 for (cnt = 1, p = commit->parents;
308                      cnt != mainline && p;
309                      cnt++)
310                         p = p->next;
311                 if (cnt != mainline || !p)
312                         die("Commit %s does not have parent %d",
313                             sha1_to_hex(commit->object.sha1), mainline);
314                 parent = p->item;
315         } else if (0 < mainline)
316                 die("Mainline was specified but commit %s is not a merge.",
317                     sha1_to_hex(commit->object.sha1));
318         else
319                 parent = commit->parents->item;
320
321         if (!(message = commit->buffer))
322                 die ("Cannot get commit message for %s",
323                                 sha1_to_hex(commit->object.sha1));
324
325         if (parent && parse_commit(parent) < 0)
326                 die("%s: cannot parse parent commit %s",
327                     me, sha1_to_hex(parent->object.sha1));
328
329         /*
330          * "commit" is an existing commit.  We would want to apply
331          * the difference it introduces since its first parent "prev"
332          * on top of the current HEAD if we are cherry-pick.  Or the
333          * reverse of it if we are revert.
334          */
335
336         msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
337                                            LOCK_DIE_ON_ERROR);
338
339         encoding = get_encoding(message);
340         if (!encoding)
341                 encoding = "UTF-8";
342         if (!git_commit_encoding)
343                 git_commit_encoding = "UTF-8";
344         if ((reencoded_message = reencode_string(message,
345                                         git_commit_encoding, encoding)))
346                 message = reencoded_message;
347
348         oneline = get_oneline(message);
349
350         if (action == REVERT) {
351                 char *oneline_body = strchr(oneline, ' ');
352
353                 base = commit;
354                 next = parent;
355                 add_to_msg("Revert \"");
356                 add_to_msg(oneline_body + 1);
357                 add_to_msg("\"\n\nThis reverts commit ");
358                 add_to_msg(sha1_to_hex(commit->object.sha1));
359
360                 if (commit->parents->next) {
361                         add_to_msg(", reversing\nchanges made to ");
362                         add_to_msg(sha1_to_hex(parent->object.sha1));
363                 }
364                 add_to_msg(".\n");
365         } else {
366                 base = parent;
367                 next = commit;
368                 set_author_ident_env(message);
369                 add_message_to_msg(message);
370                 if (no_replay) {
371                         add_to_msg("(cherry picked from commit ");
372                         add_to_msg(sha1_to_hex(commit->object.sha1));
373                         add_to_msg(")\n");
374                 }
375         }
376
377         read_cache();
378         init_merge_options(&o);
379         o.branch1 = "HEAD";
380         o.branch2 = oneline;
381
382         head_tree = parse_tree_indirect(head);
383         next_tree = next ? next->tree : empty_tree();
384         base_tree = base ? base->tree : empty_tree();
385
386         clean = merge_trees(&o,
387                             head_tree,
388                             next_tree, base_tree, &result);
389
390         if (active_cache_changed &&
391             (write_cache(index_fd, active_cache, active_nr) ||
392              commit_locked_index(&index_lock)))
393                 die("%s: Unable to write new index file", me);
394         rollback_lock_file(&index_lock);
395
396         if (!clean) {
397                 add_to_msg("\nConflicts:\n\n");
398                 for (i = 0; i < active_nr;) {
399                         struct cache_entry *ce = active_cache[i++];
400                         if (ce_stage(ce)) {
401                                 add_to_msg("\t");
402                                 add_to_msg(ce->name);
403                                 add_to_msg("\n");
404                                 while (i < active_nr && !strcmp(ce->name,
405                                                 active_cache[i]->name))
406                                         i++;
407                         }
408                 }
409                 if (commit_lock_file(&msg_file) < 0)
410                         die ("Error wrapping up %s", defmsg);
411                 fprintf(stderr, "Automatic %s failed.%s\n",
412                         me, help_msg(commit->object.sha1));
413                 rerere(allow_rerere_auto);
414                 exit(1);
415         }
416         if (commit_lock_file(&msg_file) < 0)
417                 die ("Error wrapping up %s", defmsg);
418         fprintf(stderr, "Finished one %s.\n", me);
419
420         /*
421          *
422          * If we are cherry-pick, and if the merge did not result in
423          * hand-editing, we will hit this commit and inherit the original
424          * author date and name.
425          * If we are revert, or if our cherry-pick results in a hand merge,
426          * we had better say that the current user is responsible for that.
427          */
428
429         if (!no_commit) {
430                 /* 6 is max possible length of our args array including NULL */
431                 const char *args[6];
432                 int i = 0;
433                 args[i++] = "commit";
434                 args[i++] = "-n";
435                 if (signoff)
436                         args[i++] = "-s";
437                 if (!edit) {
438                         args[i++] = "-F";
439                         args[i++] = defmsg;
440                 }
441                 args[i] = NULL;
442                 return execv_git_cmd(args);
443         }
444         free(reencoded_message);
445         free(defmsg);
446
447         return 0;
448 }
449
450 int cmd_revert(int argc, const char **argv, const char *prefix)
451 {
452         if (isatty(0))
453                 edit = 1;
454         no_replay = 1;
455         action = REVERT;
456         return revert_or_cherry_pick(argc, argv);
457 }
458
459 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
460 {
461         no_replay = 0;
462         action = CHERRY_PICK;
463         return revert_or_cherry_pick(argc, argv);
464 }