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"
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 */
23 static const char * const revert_usage[] = {
24 "git-revert [options] <commit-ish>",
25 NULL
26 };
28 static const char * const cherry_pick_usage[] = {
29 "git-cherry-pick [options] <commit-ish>",
30 NULL
31 };
33 static int edit, no_replay, no_commit, mainline;
34 static enum { REVERT, CHERRY_PICK } action;
35 static struct commit *commit;
37 static const char *me;
39 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
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 };
57 if (parse_options(argc, argv, options, usage_str, 0) != 1)
58 usage_with_options(usage_str, options);
59 arg = argv[0];
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 }
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;
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++;
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 }
103 static char *get_encoding(const char *message)
104 {
105 const char *p = message, *eol;
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 }
125 static struct lock_file msg_file;
126 static int msg_fd;
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 }
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++;
141 if (!*p)
142 add_to_msg(sha1_to_hex(commit->object.sha1));
144 p += 2;
145 add_to_msg(p);
146 return;
147 }
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;
158 for (eol = p; *eol && *eol != '\n'; eol++)
159 ; /* do nothing */
160 if (!prefixcmp(p, "author ")) {
161 char *line, *pend, *email, *timestamp;
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 }
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];
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);
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;
224 return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
225 }
227 static char *help_msg(const unsigned char *sha1)
228 {
229 static char helpbuf[1024];
230 char *msg = getenv("GIT_CHERRY_PICK_HELP");
232 if (msg)
233 return msg;
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.");
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 }
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"));
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);
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");
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;
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 }
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;
293 if (!mainline)
294 die("Commit %s is a merge but no -m option was given.",
295 sha1_to_hex(commit->object.sha1));
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;
311 if (!(message = commit->buffer))
312 die ("Cannot get commit message for %s",
313 sha1_to_hex(commit->object.sha1));
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 */
322 msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
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;
333 oneline = get_oneline(message);
335 if (action == REVERT) {
336 char *oneline_body = strchr(oneline, ' ');
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 }
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);
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 */
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);
402 return 0;
403 }
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 }
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 }