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[git/git.git] / builtin-revert.c
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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
22static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";
23
24static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";
25
26static int edit;
27static int replay;
4175e9e3 28static enum { REVERT, CHERRY_PICK } action;
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29static int no_commit;
30static struct commit *commit;
31static int needed_deref;
32
33static const char *me;
34
35#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
36
37static 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
32309f54 48 for (i = 1; i < argc; i++) {
9509af68 49 arg = argv[i];
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50 if (arg[0] != '-')
51 break;
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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 }
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64 if (i != argc - 1)
65 usage(usage_str);
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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
81static 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
52fae7de 110static char *get_encoding(const char *message)
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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
4175e9e3 132static struct lock_file msg_file;
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133static int msg_fd;
134
135static void add_to_msg(const char *string)
136{
137 int len = strlen(string);
138 if (write_in_full(msg_fd, string, len) < 0)
1dcb3b64 139 die ("Could not write to MERGE_MSG");
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140}
141
142static 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
156static 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
208static 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];
497bdc88 213 const char *argv[6];
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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 */
497bdc88
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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);
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234}
235
236static int revert_or_cherry_pick(int argc, const char **argv)
237{
238 unsigned char head[20];
239 struct commit *base, *next;
240 int i;
1a8f2741
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241 char *oneline, *reencoded_message = NULL;
242 const char *message, *encoding;
abda5227 243 const char *defmsg = xstrdup(git_path("MERGE_MSG"));
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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
abda5227 287 msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);
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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) {
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301 char *oneline_body = strchr(oneline, ' ');
302
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303 base = commit;
304 next = commit->parents->item;
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305 add_to_msg("Revert \"");
306 add_to_msg(oneline_body + 1);
307 add_to_msg("\"\n\nThis reverts commit ");
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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);
0e624044
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315 if (!replay) {
316 add_to_msg("(cherry picked from commit ");
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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",
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335 sha1_to_hex(next->object.sha1), oneline) ||
336 write_tree(head, 0, NULL)) {
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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)
abda5227 351 die ("Error wrapping up %s", defmsg);
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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) {
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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));
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361 }
362 exit(1);
363 }
364 if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
abda5227 365 die ("Error wrapping up %s", defmsg);
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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)
abda5227 379 return execl_git_cmd("commit", "-n", NULL);
9509af68 380 else
abda5227 381 return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
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382 }
383 if (reencoded_message)
384 free(reencoded_message);
385
386 return 0;
387}
388
389int 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
397int 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}