Fix read-tree not to discard errors
[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
15 /*
16  * This implements the builtins revert and cherry-pick.
17  *
18  * Copyright (c) 2007 Johannes E. Schindelin
19  *
20  * Based on git-revert.sh, which is
21  *
22  * Copyright (c) 2005 Linus Torvalds
23  * Copyright (c) 2005 Junio C Hamano
24  */
25
26 static const char * const revert_usage[] = {
27         "git-revert [options] <commit-ish>",
28         NULL
29 };
30
31 static const char * const cherry_pick_usage[] = {
32         "git-cherry-pick [options] <commit-ish>",
33         NULL
34 };
35
36 static int edit, no_replay, no_commit, mainline;
37 static enum { REVERT, CHERRY_PICK } action;
38 static struct commit *commit;
39
40 static const char *me;
41
42 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
43
44 static void parse_args(int argc, const char **argv)
45 {
46         const char * const * usage_str =
47                 action == REVERT ?  revert_usage : cherry_pick_usage;
48         unsigned char sha1[20];
49         const char *arg;
50         int noop;
51         struct option options[] = {
52                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
53                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
54                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
55                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
56                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
57                 OPT_END(),
58         };
59
60         if (parse_options(argc, argv, options, usage_str, 0) != 1)
61                 usage_with_options(usage_str, options);
62         arg = argv[0];
63
64         if (get_sha1(arg, sha1))
65                 die ("Cannot find '%s'", arg);
66         commit = (struct commit *)parse_object(sha1);
67         if (!commit)
68                 die ("Could not find %s", sha1_to_hex(sha1));
69         if (commit->object.type == OBJ_TAG) {
70                 commit = (struct commit *)
71                         deref_tag((struct object *)commit, arg, strlen(arg));
72         }
73         if (commit->object.type != OBJ_COMMIT)
74                 die ("'%s' does not point to a commit", arg);
75 }
76
77 static char *get_oneline(const char *message)
78 {
79         char *result;
80         const char *p = message, *abbrev, *eol;
81         int abbrev_len, oneline_len;
82
83         if (!p)
84                 die ("Could not read commit message of %s",
85                                 sha1_to_hex(commit->object.sha1));
86         while (*p && (*p != '\n' || p[1] != '\n'))
87                 p++;
88
89         if (*p) {
90                 p += 2;
91                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
92                         ; /* do nothing */
93         } else
94                 eol = p;
95         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
96         abbrev_len = strlen(abbrev);
97         oneline_len = eol - p;
98         result = xmalloc(abbrev_len + 5 + oneline_len);
99         memcpy(result, abbrev, abbrev_len);
100         memcpy(result + abbrev_len, "... ", 4);
101         memcpy(result + abbrev_len + 4, p, oneline_len);
102         result[abbrev_len + 4 + oneline_len] = '\0';
103         return result;
104 }
105
106 static char *get_encoding(const char *message)
107 {
108         const char *p = message, *eol;
109
110         if (!p)
111                 die ("Could not read commit message of %s",
112                                 sha1_to_hex(commit->object.sha1));
113         while (*p && *p != '\n') {
114                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
115                         ; /* do nothing */
116                 if (!prefixcmp(p, "encoding ")) {
117                         char *result = xmalloc(eol - 8 - p);
118                         strlcpy(result, p + 9, eol - 8 - p);
119                         return result;
120                 }
121                 p = eol;
122                 if (*p == '\n')
123                         p++;
124         }
125         return NULL;
126 }
127
128 static struct lock_file msg_file;
129 static int msg_fd;
130
131 static void add_to_msg(const char *string)
132 {
133         int len = strlen(string);
134         if (write_in_full(msg_fd, string, len) < 0)
135                 die ("Could not write to MERGE_MSG");
136 }
137
138 static void add_message_to_msg(const char *message)
139 {
140         const char *p = message;
141         while (*p && (*p != '\n' || p[1] != '\n'))
142                 p++;
143
144         if (!*p)
145                 add_to_msg(sha1_to_hex(commit->object.sha1));
146
147         p += 2;
148         add_to_msg(p);
149         return;
150 }
151
152 static void set_author_ident_env(const char *message)
153 {
154         const char *p = message;
155         if (!p)
156                 die ("Could not read commit message of %s",
157                                 sha1_to_hex(commit->object.sha1));
158         while (*p && *p != '\n') {
159                 const char *eol;
160
161                 for (eol = p; *eol && *eol != '\n'; eol++)
162                         ; /* do nothing */
163                 if (!prefixcmp(p, "author ")) {
164                         char *line, *pend, *email, *timestamp;
165
166                         p += 7;
167                         line = xmemdupz(p, eol - p);
168                         email = strchr(line, '<');
169                         if (!email)
170                                 die ("Could not extract author email from %s",
171                                         sha1_to_hex(commit->object.sha1));
172                         if (email == line)
173                                 pend = line;
174                         else
175                                 for (pend = email; pend != line + 1 &&
176                                                 isspace(pend[-1]); pend--);
177                                         ; /* do nothing */
178                         *pend = '\0';
179                         email++;
180                         timestamp = strchr(email, '>');
181                         if (!timestamp)
182                                 die ("Could not extract author email from %s",
183                                         sha1_to_hex(commit->object.sha1));
184                         *timestamp = '\0';
185                         for (timestamp++; *timestamp && isspace(*timestamp);
186                                         timestamp++)
187                                 ; /* do nothing */
188                         setenv("GIT_AUTHOR_NAME", line, 1);
189                         setenv("GIT_AUTHOR_EMAIL", email, 1);
190                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
191                         free(line);
192                         return;
193                 }
194                 p = eol;
195                 if (*p == '\n')
196                         p++;
197         }
198         die ("No author information found in %s",
199                         sha1_to_hex(commit->object.sha1));
200 }
201
202 static int merge_recursive(const char *base_sha1,
203                 const char *head_sha1, const char *head_name,
204                 const char *next_sha1, const char *next_name)
205 {
206         char buffer[256];
207         const char *argv[6];
208
209         sprintf(buffer, "GITHEAD_%s", head_sha1);
210         setenv(buffer, head_name, 1);
211         sprintf(buffer, "GITHEAD_%s", next_sha1);
212         setenv(buffer, next_name, 1);
213
214         /*
215          * This three way merge is an interesting one.  We are at
216          * $head, and would want to apply the change between $commit
217          * and $prev on top of us (when reverting), or the change between
218          * $prev and $commit on top of us (when cherry-picking or replaying).
219          */
220         argv[0] = "merge-recursive";
221         argv[1] = base_sha1;
222         argv[2] = "--";
223         argv[3] = head_sha1;
224         argv[4] = next_sha1;
225         argv[5] = NULL;
226
227         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
228 }
229
230 static char *help_msg(const unsigned char *sha1)
231 {
232         static char helpbuf[1024];
233         char *msg = getenv("GIT_CHERRY_PICK_HELP");
234
235         if (msg)
236                 return msg;
237
238         strcpy(helpbuf, "  After resolving the conflicts,\n"
239                "mark the corrected paths with 'git add <paths>' "
240                "or 'git rm <paths>' and commit the result.");
241
242         if (action == CHERRY_PICK) {
243                 sprintf(helpbuf + strlen(helpbuf),
244                         "\nWhen commiting, use the option "
245                         "'-c %s' to retain authorship and message.",
246                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
247         }
248         return helpbuf;
249 }
250
251 static int index_is_dirty(void)
252 {
253         struct rev_info rev;
254         init_revisions(&rev, NULL);
255         setup_revisions(0, NULL, &rev, "HEAD");
256         DIFF_OPT_SET(&rev.diffopt, QUIET);
257         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
258         run_diff_index(&rev, 1);
259         return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
260 }
261
262 static int revert_or_cherry_pick(int argc, const char **argv)
263 {
264         unsigned char head[20];
265         struct commit *base, *next, *parent;
266         int i;
267         char *oneline, *reencoded_message = NULL;
268         const char *message, *encoding;
269         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
270
271         git_config(git_default_config);
272         me = action == REVERT ? "revert" : "cherry-pick";
273         setenv(GIT_REFLOG_ACTION, me, 0);
274         parse_args(argc, argv);
275
276         /* this is copied from the shell script, but it's never triggered... */
277         if (action == REVERT && !no_replay)
278                 die("revert is incompatible with replay");
279
280         if (no_commit) {
281                 /*
282                  * We do not intend to commit immediately.  We just want to
283                  * merge the differences in, so let's compute the tree
284                  * that represents the "current" state for merge-recursive
285                  * to work on.
286                  */
287                 if (write_cache_as_tree(head, 0, NULL))
288                         die ("Your index file is unmerged.");
289         } else {
290                 if (get_sha1("HEAD", head))
291                         die ("You do not have a valid HEAD");
292                 if (read_cache() < 0)
293                         die("could not read the index");
294                 if (index_is_dirty())
295                         die ("Dirty index: cannot %s", me);
296                 discard_cache();
297         }
298
299         if (!commit->parents)
300                 die ("Cannot %s a root commit", me);
301         if (commit->parents->next) {
302                 /* Reverting or cherry-picking a merge commit */
303                 int cnt;
304                 struct commit_list *p;
305
306                 if (!mainline)
307                         die("Commit %s is a merge but no -m option was given.",
308                             sha1_to_hex(commit->object.sha1));
309
310                 for (cnt = 1, p = commit->parents;
311                      cnt != mainline && p;
312                      cnt++)
313                         p = p->next;
314                 if (cnt != mainline || !p)
315                         die("Commit %s does not have parent %d",
316                             sha1_to_hex(commit->object.sha1), mainline);
317                 parent = p->item;
318         } else if (0 < mainline)
319                 die("Mainline was specified but commit %s is not a merge.",
320                     sha1_to_hex(commit->object.sha1));
321         else
322                 parent = commit->parents->item;
323
324         if (!(message = commit->buffer))
325                 die ("Cannot get commit message for %s",
326                                 sha1_to_hex(commit->object.sha1));
327
328         /*
329          * "commit" is an existing commit.  We would want to apply
330          * the difference it introduces since its first parent "prev"
331          * on top of the current HEAD if we are cherry-pick.  Or the
332          * reverse of it if we are revert.
333          */
334
335         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
336
337         encoding = get_encoding(message);
338         if (!encoding)
339                 encoding = "utf-8";
340         if (!git_commit_encoding)
341                 git_commit_encoding = "utf-8";
342         if ((reencoded_message = reencode_string(message,
343                                         git_commit_encoding, encoding)))
344                 message = reencoded_message;
345
346         oneline = get_oneline(message);
347
348         if (action == REVERT) {
349                 char *oneline_body = strchr(oneline, ' ');
350
351                 base = commit;
352                 next = parent;
353                 add_to_msg("Revert \"");
354                 add_to_msg(oneline_body + 1);
355                 add_to_msg("\"\n\nThis reverts commit ");
356                 add_to_msg(sha1_to_hex(commit->object.sha1));
357                 add_to_msg(".\n");
358         } else {
359                 base = parent;
360                 next = commit;
361                 set_author_ident_env(message);
362                 add_message_to_msg(message);
363                 if (no_replay) {
364                         add_to_msg("(cherry picked from commit ");
365                         add_to_msg(sha1_to_hex(commit->object.sha1));
366                         add_to_msg(")\n");
367                 }
368         }
369
370         if (merge_recursive(sha1_to_hex(base->object.sha1),
371                                 sha1_to_hex(head), "HEAD",
372                                 sha1_to_hex(next->object.sha1), oneline) ||
373                         write_cache_as_tree(head, 0, NULL)) {
374                 add_to_msg("\nConflicts:\n\n");
375                 read_cache();
376                 for (i = 0; i < active_nr;) {
377                         struct cache_entry *ce = active_cache[i++];
378                         if (ce_stage(ce)) {
379                                 add_to_msg("\t");
380                                 add_to_msg(ce->name);
381                                 add_to_msg("\n");
382                                 while (i < active_nr && !strcmp(ce->name,
383                                                 active_cache[i]->name))
384                                         i++;
385                         }
386                 }
387                 if (commit_lock_file(&msg_file) < 0)
388                         die ("Error wrapping up %s", defmsg);
389                 fprintf(stderr, "Automatic %s failed.%s\n",
390                         me, help_msg(commit->object.sha1));
391                 exit(1);
392         }
393         if (commit_lock_file(&msg_file) < 0)
394                 die ("Error wrapping up %s", defmsg);
395         fprintf(stderr, "Finished one %s.\n", me);
396
397         /*
398          *
399          * If we are cherry-pick, and if the merge did not result in
400          * hand-editing, we will hit this commit and inherit the original
401          * author date and name.
402          * If we are revert, or if our cherry-pick results in a hand merge,
403          * we had better say that the current user is responsible for that.
404          */
405
406         if (!no_commit) {
407                 if (edit)
408                         return execl_git_cmd("commit", "-n", NULL);
409                 else
410                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
411         }
412         free(reencoded_message);
413
414         return 0;
415 }
416
417 int cmd_revert(int argc, const char **argv, const char *prefix)
418 {
419         if (isatty(0))
420                 edit = 1;
421         no_replay = 1;
422         action = REVERT;
423         return revert_or_cherry_pick(argc, argv);
424 }
425
426 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
427 {
428         no_replay = 0;
429         action = CHERRY_PICK;
430         return revert_or_cherry_pick(argc, argv);
431 }