Use $(RM) in Makefiles instead of 'rm -f'
[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
11 /*
12  * This implements the builtins revert and cherry-pick.
13  *
14  * Copyright (c) 2007 Johannes E. Schindelin
15  *
16  * Based on git-revert.sh, which is
17  *
18  * Copyright (c) 2005 Linus Torvalds
19  * Copyright (c) 2005 Junio C Hamano
20  */
21
22 static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";
23
24 static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
25
26 static int edit;
27 static int replay;
28 static enum { REVERT, CHERRY_PICK } action;
29 static int no_commit;
30 static struct commit *commit;
31 static int needed_deref;
32
33 static const char *me;
34
35 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
36
37 static void parse_options(int argc, const char **argv)
38 {
39         const char *usage_str = action == REVERT ?
40                 revert_usage : cherry_pick_usage;
41         unsigned char sha1[20];
42         const char *arg;
43         int i;
44
45         if (argc < 2)
46                 usage(usage_str);
47
48         for (i = 1; i < argc; i++) {
49                 arg = argv[i];
50                 if (arg[0] != '-')
51                         break;
52                 if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
53                         no_commit = 1;
54                 else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
55                         edit = 1;
56                 else if (!strcmp(arg, "--no-edit"))
57                         edit = 0;
58                 else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
59                                 "to-expose-my-private-commit-object-name"))
60                         replay = 0;
61                 else if (strcmp(arg, "-r"))
62                         usage(usage_str);
63         }
64         if (i != argc - 1)
65                 usage(usage_str);
66         arg = argv[argc - 1];
67         if (get_sha1(arg, sha1))
68                 die ("Cannot find '%s'", arg);
69         commit = (struct commit *)parse_object(sha1);
70         if (!commit)
71                 die ("Could not find %s", sha1_to_hex(sha1));
72         if (commit->object.type == OBJ_TAG) {
73                 commit = (struct commit *)
74                         deref_tag((struct object *)commit, arg, strlen(arg));
75                 needed_deref = 1;
76         }
77         if (commit->object.type != OBJ_COMMIT)
78                 die ("'%s' does not point to a commit", arg);
79 }
80
81 static char *get_oneline(const char *message)
82 {
83         char *result;
84         const char *p = message, *abbrev, *eol;
85         int abbrev_len, oneline_len;
86
87         if (!p)
88                 die ("Could not read commit message of %s",
89                                 sha1_to_hex(commit->object.sha1));
90         while (*p && (*p != '\n' || p[1] != '\n'))
91                 p++;
92
93         if (*p) {
94                 p += 2;
95                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
96                         ; /* do nothing */
97         } else
98                 eol = p;
99         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
100         abbrev_len = strlen(abbrev);
101         oneline_len = eol - p;
102         result = xmalloc(abbrev_len + 5 + oneline_len);
103         memcpy(result, abbrev, abbrev_len);
104         memcpy(result + abbrev_len, "... ", 4);
105         memcpy(result + abbrev_len + 4, p, oneline_len);
106         result[abbrev_len + 4 + oneline_len] = '\0';
107         return result;
108 }
109
110 static char *get_encoding(const char *message)
111 {
112         const char *p = message, *eol;
113
114         if (!p)
115                 die ("Could not read commit message of %s",
116                                 sha1_to_hex(commit->object.sha1));
117         while (*p && *p != '\n') {
118                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
119                         ; /* do nothing */
120                 if (!prefixcmp(p, "encoding ")) {
121                         char *result = xmalloc(eol - 8 - p);
122                         strlcpy(result, p + 9, eol - 8 - p);
123                         return result;
124                 }
125                 p = eol;
126                 if (*p == '\n')
127                         p++;
128         }
129         return NULL;
130 }
131
132 static struct lock_file msg_file;
133 static int msg_fd;
134
135 static void add_to_msg(const char *string)
136 {
137         int len = strlen(string);
138         if (write_in_full(msg_fd, string, len) < 0)
139                 die ("Could not write to MERGE_MSG");
140 }
141
142 static void add_message_to_msg(const char *message)
143 {
144         const char *p = message;
145         while (*p && (*p != '\n' || p[1] != '\n'))
146                 p++;
147
148         if (!*p)
149                 add_to_msg(sha1_to_hex(commit->object.sha1));
150
151         p += 2;
152         add_to_msg(p);
153         return;
154 }
155
156 static void set_author_ident_env(const char *message)
157 {
158         const char *p = message;
159         if (!p)
160                 die ("Could not read commit message of %s",
161                                 sha1_to_hex(commit->object.sha1));
162         while (*p && *p != '\n') {
163                 const char *eol;
164
165                 for (eol = p; *eol && *eol != '\n'; eol++)
166                         ; /* do nothing */
167                 if (!prefixcmp(p, "author ")) {
168                         char *line, *pend, *email, *timestamp;
169
170                         p += 7;
171                         line = xmalloc(eol + 1 - p);
172                         memcpy(line, p, eol - p);
173                         line[eol - p] = '\0';
174                         email = strchr(line, '<');
175                         if (!email)
176                                 die ("Could not extract author email from %s",
177                                         sha1_to_hex(commit->object.sha1));
178                         if (email == line)
179                                 pend = line;
180                         else
181                                 for (pend = email; pend != line + 1 &&
182                                                 isspace(pend[-1]); pend--);
183                                         ; /* do nothing */
184                         *pend = '\0';
185                         email++;
186                         timestamp = strchr(email, '>');
187                         if (!timestamp)
188                                 die ("Could not extract author email from %s",
189                                         sha1_to_hex(commit->object.sha1));
190                         *timestamp = '\0';
191                         for (timestamp++; *timestamp && isspace(*timestamp);
192                                         timestamp++)
193                                 ; /* do nothing */
194                         setenv("GIT_AUTHOR_NAME", line, 1);
195                         setenv("GIT_AUTHOR_EMAIL", email, 1);
196                         setenv("GIT_AUTHOR_DATE", timestamp, 1);
197                         free(line);
198                         return;
199                 }
200                 p = eol;
201                 if (*p == '\n')
202                         p++;
203         }
204         die ("No author information found in %s",
205                         sha1_to_hex(commit->object.sha1));
206 }
207
208 static int merge_recursive(const char *base_sha1,
209                 const char *head_sha1, const char *head_name,
210                 const char *next_sha1, const char *next_name)
211 {
212         char buffer[256];
213         const char *argv[6];
214
215         sprintf(buffer, "GITHEAD_%s", head_sha1);
216         setenv(buffer, head_name, 1);
217         sprintf(buffer, "GITHEAD_%s", next_sha1);
218         setenv(buffer, next_name, 1);
219
220         /*
221          * This three way merge is an interesting one.  We are at
222          * $head, and would want to apply the change between $commit
223          * and $prev on top of us (when reverting), or the change between
224          * $prev and $commit on top of us (when cherry-picking or replaying).
225          */
226         argv[0] = "merge-recursive";
227         argv[1] = base_sha1;
228         argv[2] = "--";
229         argv[3] = head_sha1;
230         argv[4] = next_sha1;
231         argv[5] = NULL;
232
233         return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
234 }
235
236 static int revert_or_cherry_pick(int argc, const char **argv)
237 {
238         unsigned char head[20];
239         struct commit *base, *next;
240         int i;
241         char *oneline, *reencoded_message = NULL;
242         const char *message, *encoding;
243         const char *defmsg = xstrdup(git_path("MERGE_MSG"));
244
245         git_config(git_default_config);
246         me = action == REVERT ? "revert" : "cherry-pick";
247         setenv(GIT_REFLOG_ACTION, me, 0);
248         parse_options(argc, argv);
249
250         /* this is copied from the shell script, but it's never triggered... */
251         if (action == REVERT && replay)
252                 die("revert is incompatible with replay");
253
254         if (no_commit) {
255                 /*
256                  * We do not intend to commit immediately.  We just want to
257                  * merge the differences in.
258                  */
259                 if (write_tree(head, 0, NULL))
260                         die ("Your index file is unmerged.");
261         } else {
262                 struct wt_status s;
263
264                 if (get_sha1("HEAD", head))
265                         die ("You do not have a valid HEAD");
266                 wt_status_prepare(&s);
267                 if (s.commitable || s.workdir_dirty)
268                         die ("Dirty index: cannot %s", me);
269                 discard_cache();
270         }
271
272         if (!commit->parents)
273                 die ("Cannot %s a root commit", me);
274         if (commit->parents->next)
275                 die ("Cannot %s a multi-parent commit.", me);
276         if (!(message = commit->buffer))
277                 die ("Cannot get commit message for %s",
278                                 sha1_to_hex(commit->object.sha1));
279
280         /*
281          * "commit" is an existing commit.  We would want to apply
282          * the difference it introduces since its first parent "prev"
283          * on top of the current HEAD if we are cherry-pick.  Or the
284          * reverse of it if we are revert.
285          */
286
287         msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
288
289         encoding = get_encoding(message);
290         if (!encoding)
291                 encoding = "utf-8";
292         if (!git_commit_encoding)
293                 git_commit_encoding = "utf-8";
294         if ((reencoded_message = reencode_string(message,
295                                         git_commit_encoding, encoding)))
296                 message = reencoded_message;
297
298         oneline = get_oneline(message);
299
300         if (action == REVERT) {
301                 char *oneline_body = strchr(oneline, ' ');
302
303                 base = commit;
304                 next = commit->parents->item;
305                 add_to_msg("Revert \"");
306                 add_to_msg(oneline_body + 1);
307                 add_to_msg("\"\n\nThis reverts commit ");
308                 add_to_msg(sha1_to_hex(commit->object.sha1));
309                 add_to_msg(".\n");
310         } else {
311                 base = commit->parents->item;
312                 next = commit;
313                 set_author_ident_env(message);
314                 add_message_to_msg(message);
315                 if (!replay) {
316                         add_to_msg("(cherry picked from commit ");
317                         add_to_msg(sha1_to_hex(commit->object.sha1));
318                         add_to_msg(")\n");
319                 }
320         }
321         if (needed_deref) {
322                 add_to_msg("(original 'git ");
323                 add_to_msg(me);
324                 add_to_msg("' arguments: ");
325                 for (i = 0; i < argc; i++) {
326                         if (i)
327                                 add_to_msg(" ");
328                         add_to_msg(argv[i]);
329                 }
330                 add_to_msg(")\n");
331         }
332
333         if (merge_recursive(sha1_to_hex(base->object.sha1),
334                                 sha1_to_hex(head), "HEAD",
335                                 sha1_to_hex(next->object.sha1), oneline) ||
336                         write_tree(head, 0, NULL)) {
337                 add_to_msg("\nConflicts:\n\n");
338                 read_cache();
339                 for (i = 0; i < active_nr;) {
340                         struct cache_entry *ce = active_cache[i++];
341                         if (ce_stage(ce)) {
342                                 add_to_msg("\t");
343                                 add_to_msg(ce->name);
344                                 add_to_msg("\n");
345                                 while (i < active_nr && !strcmp(ce->name,
346                                                 active_cache[i]->name))
347                                         i++;
348                         }
349                 }
350                 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
351                         die ("Error wrapping up %s", defmsg);
352                 fprintf(stderr, "Automatic %s failed.  "
353                         "After resolving the conflicts,\n"
354                         "mark the corrected paths with 'git-add <paths>'\n"
355                         "and commit the result.\n", me);
356                 if (action == CHERRY_PICK) {
357                         fprintf(stderr, "When commiting, use the option "
358                                 "'-c %s' to retain authorship and message.\n",
359                                 find_unique_abbrev(commit->object.sha1,
360                                         DEFAULT_ABBREV));
361                 }
362                 exit(1);
363         }
364         if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
365                 die ("Error wrapping up %s", defmsg);
366         fprintf(stderr, "Finished one %s.\n", me);
367
368         /*
369          *
370          * If we are cherry-pick, and if the merge did not result in
371          * hand-editing, we will hit this commit and inherit the original
372          * author date and name.
373          * If we are revert, or if our cherry-pick results in a hand merge,
374          * we had better say that the current user is responsible for that.
375          */
376
377         if (!no_commit) {
378                 if (edit)
379                         return execl_git_cmd("commit", "-n", NULL);
380                 else
381                         return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
382         }
383         if (reencoded_message)
384                 free(reencoded_message);
385
386         return 0;
387 }
388
389 int cmd_revert(int argc, const char **argv, const char *prefix)
390 {
391         if (isatty(0))
392                 edit = 1;
393         action = REVERT;
394         return revert_or_cherry_pick(argc, argv);
395 }
396
397 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
398 {
399         replay = 1;
400         action = CHERRY_PICK;
401         return revert_or_cherry_pick(argc, argv);
402 }