Merge branch 'kh/commit'
[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
12 /*
13  * This implements the builtins revert and cherry-pick.
14  *
15  * Copyright (c) 2007 Johannes E. Schindelin
16  *
17  * Based on git-revert.sh, which is
18  *
19  * Copyright (c) 2005 Linus Torvalds
20  * Copyright (c) 2005 Junio C Hamano
21  */
22
23 static const char * const revert_usage[] = {
24         "git-revert [options] <commit-ish>",
25         NULL
26 };
27
28 static const char * const cherry_pick_usage[] = {
29         "git-cherry-pick [options] <commit-ish>",
30         NULL
31 };
32
33 static int edit, no_replay, no_commit, mainline;
34 static enum { REVERT, CHERRY_PICK } action;
35 static struct commit *commit;
36
37 static const char *me;
38
39 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
40
41 static void parse_args(int argc, const char **argv)
42 {
43         const char * const * usage_str =
44                 action == REVERT ?  revert_usage : cherry_pick_usage;
45         unsigned char sha1[20];
46         const char *arg;
47         int noop;
48         struct option options[] = {
49                 OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
50                 OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
51                 OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
52                 OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
53                 OPT_INTEGER('m', "mainline", &mainline, "parent number"),
54                 OPT_END(),
55         };
56
57         if (parse_options(argc, argv, options, usage_str, 0) != 1)
58                 usage_with_options(usage_str, options);
59         arg = argv[0];
60
61         if (get_sha1(arg, sha1))
62                 die ("Cannot find '%s'", arg);
63         commit = (struct commit *)parse_object(sha1);
64         if (!commit)
65                 die ("Could not find %s", sha1_to_hex(sha1));
66         if (commit->object.type == OBJ_TAG) {
67                 commit = (struct commit *)
68                         deref_tag((struct object *)commit, arg, strlen(arg));
69         }
70         if (commit->object.type != OBJ_COMMIT)
71                 die ("'%s' does not point to a commit", arg);
72 }
73
74 static char *get_oneline(const char *message)
75 {
76         char *result;
77         const char *p = message, *abbrev, *eol;
78         int abbrev_len, oneline_len;
79
80         if (!p)
81                 die ("Could not read commit message of %s",
82                                 sha1_to_hex(commit->object.sha1));
83         while (*p && (*p != '\n' || p[1] != '\n'))
84                 p++;
85
86         if (*p) {
87                 p += 2;
88                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
89                         ; /* do nothing */
90         } else
91                 eol = p;
92         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
93         abbrev_len = strlen(abbrev);
94         oneline_len = eol - p;
95         result = xmalloc(abbrev_len + 5 + oneline_len);
96         memcpy(result, abbrev, abbrev_len);
97         memcpy(result + abbrev_len, "... ", 4);
98         memcpy(result + abbrev_len + 4, p, oneline_len);
99         result[abbrev_len + 4 + oneline_len] = '\0';
100         return result;
101 }
102
103 static char *get_encoding(const char *message)
104 {
105         const char *p = message, *eol;
106
107         if (!p)
108                 die ("Could not read commit message of %s",
109                                 sha1_to_hex(commit->object.sha1));
110         while (*p && *p != '\n') {
111                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
112                         ; /* do nothing */
113                 if (!prefixcmp(p, "encoding ")) {
114                         char *result = xmalloc(eol - 8 - p);
115                         strlcpy(result, p + 9, eol - 8 - p);
116                         return result;
117                 }
118                 p = eol;
119                 if (*p == '\n')
120                         p++;
121         }
122         return NULL;
123 }
124
125 static struct lock_file msg_file;
126 static int msg_fd;
127
128 static void add_to_msg(const char *string)
129 {
130         int len = strlen(string);
131         if (write_in_full(msg_fd, string, len) < 0)
132                 die ("Could not write to MERGE_MSG");
133 }
134
135 static void add_message_to_msg(const char *message)
136 {
137         const char *p = message;
138         while (*p && (*p != '\n' || p[1] != '\n'))
139                 p++;
140
141         if (!*p)
142                 add_to_msg(sha1_to_hex(commit->object.sha1));
143
144         p += 2;
145         add_to_msg(p);
146         return;
147 }
148
149 static void set_author_ident_env(const char *message)
150 {
151         const char *p = message;
152         if (!p)
153                 die ("Could not read commit message of %s",
154                                 sha1_to_hex(commit->object.sha1));
155         while (*p && *p != '\n') {
156                 const char *eol;
157
158                 for (eol = p; *eol && *eol != '\n'; eol++)
159                         ; /* do nothing */
160                 if (!prefixcmp(p, "author ")) {
161                         char *line, *pend, *email, *timestamp;
162
163                         p += 7;
164                         line = xmemdupz(p, eol - p);
165                         email = strchr(line, '<');
166                         if (!email)
167                                 die ("Could not extract author email from %s",
168                                         sha1_to_hex(commit->object.sha1));
169                         if (email == line)
170                                 pend = line;
171                         else
172                                 for (pend = email; pend != line + 1 &&
173                                                 isspace(pend[-1]); pend--);
174                                         ; /* do nothing */
175                         *pend = '\0';
176                         email++;
177                         timestamp = strchr(email, '>');
178                         if (!timestamp)
179                                 die ("Could not extract author email from %s",
180                                         sha1_to_hex(commit->object.sha1));
181                         *timestamp = '\0';
182                         for (timestamp++; *timestamp && isspace(*timestamp);
183                                         timestamp++)
184                                 ; /* do nothing */
185                         setenv("GIT_AUTHOR_NAME", line, 1);
186                         setenv("GIT_AUTHOR_EMAIL", email, 1);
187                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
188                         free(line);
189                         return;
190                 }
191                 p = eol;
192                 if (*p == '\n')
193                         p++;
194         }
195         die ("No author information found in %s",
196                         sha1_to_hex(commit->object.sha1));
197 }
198
199 static int merge_recursive(const char *base_sha1,
200                 const char *head_sha1, const char *head_name,
201                 const char *next_sha1, const char *next_name)
202 {
203         char buffer[256];
204         const char *argv[6];
205
206         sprintf(buffer, "GITHEAD_%s", head_sha1);
207         setenv(buffer, head_name, 1);
208         sprintf(buffer, "GITHEAD_%s", next_sha1);
209         setenv(buffer, next_name, 1);
210
211         /*
212          * This three way merge is an interesting one.  We are at
213          * $head, and would want to apply the change between $commit
214          * and $prev on top of us (when reverting), or the change between
215          * $prev and $commit on top of us (when cherry-picking or replaying).
216          */
217         argv[0] = "merge-recursive";
218         argv[1] = base_sha1;
219         argv[2] = "--";
220         argv[3] = head_sha1;
221         argv[4] = next_sha1;
222         argv[5] = NULL;
223
224         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
225 }
226
227 static char *help_msg(const unsigned char *sha1)
228 {
229         static char helpbuf[1024];
230         char *msg = getenv("GIT_CHERRY_PICK_HELP");
231
232         if (msg)
233                 return msg;
234
235         strcpy(helpbuf, "  After resolving the conflicts,\n"
236                "mark the corrected paths with 'git add <paths>' "
237                "or 'git rm <paths>' and commit the result.");
238
239         if (action == CHERRY_PICK) {
240                 sprintf(helpbuf + strlen(helpbuf),
241                         "\nWhen commiting, use the option "
242                         "'-c %s' to retain authorship and message.",
243                         find_unique_abbrev(sha1, DEFAULT_ABBREV));
244         }
245         return helpbuf;
246 }
247
248 static int revert_or_cherry_pick(int argc, const char **argv)
249 {
250         unsigned char head[20];
251         struct commit *base, *next, *parent;
252         int i;
253         char *oneline, *reencoded_message = NULL;
254         const char *message, *encoding;
255         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
256
257         git_config(git_default_config);
258         me = action == REVERT ? "revert" : "cherry-pick";
259         setenv(GIT_REFLOG_ACTION, me, 0);
260         parse_args(argc, argv);
261
262         /* this is copied from the shell script, but it's never triggered... */
263         if (action == REVERT && !no_replay)
264                 die("revert is incompatible with replay");
265
266         if (no_commit) {
267                 /*
268                  * We do not intend to commit immediately.  We just want to
269                  * merge the differences in, so let's compute the tree
270                  * that represents the "current" state for merge-recursive
271                  * to work on.
272                  */
273                 if (write_tree(head, 0, NULL))
274                         die ("Your index file is unmerged.");
275         } else {
276                 struct wt_status s;
277
278                 if (get_sha1("HEAD", head))
279                         die ("You do not have a valid HEAD");
280                 wt_status_prepare(&s);
281                 if (s.commitable)
282                         die ("Dirty index: cannot %s", me);
283                 discard_cache();
284         }
285
286         if (!commit->parents)
287                 die ("Cannot %s a root commit", me);
288         if (commit->parents->next) {
289                 /* Reverting or cherry-picking a merge commit */
290                 int cnt;
291                 struct commit_list *p;
292
293                 if (!mainline)
294                         die("Commit %s is a merge but no -m option was given.",
295                             sha1_to_hex(commit->object.sha1));
296
297                 for (cnt = 1, p = commit->parents;
298                      cnt != mainline && p;
299                      cnt++)
300                         p = p->next;
301                 if (cnt != mainline || !p)
302                         die("Commit %s does not have parent %d",
303                             sha1_to_hex(commit->object.sha1), mainline);
304                 parent = p->item;
305         } else if (0 < mainline)
306                 die("Mainline was specified but commit %s is not a merge.",
307                     sha1_to_hex(commit->object.sha1));
308         else
309                 parent = commit->parents->item;
310
311         if (!(message = commit->buffer))
312                 die ("Cannot get commit message for %s",
313                                 sha1_to_hex(commit->object.sha1));
314
315         /*
316          * "commit" is an existing commit.  We would want to apply
317          * the difference it introduces since its first parent "prev"
318          * on top of the current HEAD if we are cherry-pick.  Or the
319          * reverse of it if we are revert.
320          */
321
322         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
323
324         encoding = get_encoding(message);
325         if (!encoding)
326                 encoding = "utf-8";
327         if (!git_commit_encoding)
328                 git_commit_encoding = "utf-8";
329         if ((reencoded_message = reencode_string(message,
330                                         git_commit_encoding, encoding)))
331                 message = reencoded_message;
332
333         oneline = get_oneline(message);
334
335         if (action == REVERT) {
336                 char *oneline_body = strchr(oneline, ' ');
337
338                 base = commit;
339                 next = parent;
340                 add_to_msg("Revert \"");
341                 add_to_msg(oneline_body + 1);
342                 add_to_msg("\"\n\nThis reverts commit ");
343                 add_to_msg(sha1_to_hex(commit->object.sha1));
344                 add_to_msg(".\n");
345         } else {
346                 base = parent;
347                 next = commit;
348                 set_author_ident_env(message);
349                 add_message_to_msg(message);
350                 if (no_replay) {
351                         add_to_msg("(cherry picked from commit ");
352                         add_to_msg(sha1_to_hex(commit->object.sha1));
353                         add_to_msg(")\n");
354                 }
355         }
356
357         if (merge_recursive(sha1_to_hex(base->object.sha1),
358                                 sha1_to_hex(head), "HEAD",
359                                 sha1_to_hex(next->object.sha1), oneline) ||
360                         write_tree(head, 0, NULL)) {
361                 add_to_msg("\nConflicts:\n\n");
362                 read_cache();
363                 for (i = 0; i < active_nr;) {
364                         struct cache_entry *ce = active_cache[i++];
365                         if (ce_stage(ce)) {
366                                 add_to_msg("\t");
367                                 add_to_msg(ce->name);
368                                 add_to_msg("\n");
369                                 while (i < active_nr && !strcmp(ce->name,
370                                                 active_cache[i]->name))
371                                         i++;
372                         }
373                 }
374                 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
375                         die ("Error wrapping up %s", defmsg);
376                 fprintf(stderr, "Automatic %s failed.%s\n",
377                         me, help_msg(commit->object.sha1));
378                 exit(1);
379         }
380         if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
381                 die ("Error wrapping up %s", defmsg);
382         fprintf(stderr, "Finished one %s.\n", me);
383
384         /*
385          *
386          * If we are cherry-pick, and if the merge did not result in
387          * hand-editing, we will hit this commit and inherit the original
388          * author date and name.
389          * If we are revert, or if our cherry-pick results in a hand merge,
390          * we had better say that the current user is responsible for that.
391          */
392
393         if (!no_commit) {
394                 if (edit)
395                         return execl_git_cmd("commit", "-n", NULL);
396                 else
397                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
398         }
399         if (reencoded_message)
400                 free(reencoded_message);
401
402         return 0;
403 }
404
405 int cmd_revert(int argc, const char **argv, const char *prefix)
406 {
407         if (isatty(0))
408                 edit = 1;
409         no_replay = 1;
410         action = REVERT;
411         return revert_or_cherry_pick(argc, argv);
412 }
413
414 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
415 {
416         no_replay = 0;
417         action = CHERRY_PICK;
418         return revert_or_cherry_pick(argc, argv);
419 }