summaryrefslogtreecommitdiff
path: root/builtin-revert.c
blob: ea2f15b977a8b62189755ae89e3ee704b45afae8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
#include "cache.h"
#include "builtin.h"
#include "object.h"
#include "commit.h"
#include "tag.h"
#include "wt-status.h"
#include "run-command.h"
#include "exec_cmd.h"
#include "utf8.h"

/*
 * This implements the builtins revert and cherry-pick.
 *
 * Copyright (c) 2007 Johannes E. Schindelin
 *
 * Based on git-revert.sh, which is
 *
 * Copyright (c) 2005 Linus Torvalds
 * Copyright (c) 2005 Junio C Hamano
 */

static const char *revert_usage = "git-revert [--edit | --no-edit] [-n] <commit-ish>";

static const char *cherry_pick_usage = "git-cherry-pick [--edit] [-n] [-r] [-x] <commit-ish>";

static int edit;
static int replay;
enum { REVERT, CHERRY_PICK } action;
static int no_commit;
static struct commit *commit;
static int needed_deref;

static const char *me;

#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"

static void parse_options(int argc, const char **argv)
{
	const char *usage_str = action == REVERT ?
		revert_usage : cherry_pick_usage;
	unsigned char sha1[20];
	const char *arg;
	int i;

	if (argc < 2)
		usage(usage_str);

	for (i = 1; i < argc - 1; i++) {
		arg = argv[i];
		if (!strcmp(arg, "-n") || !strcmp(arg, "--no-commit"))
			no_commit = 1;
		else if (!strcmp(arg, "-e") || !strcmp(arg, "--edit"))
			edit = 1;
		else if (!strcmp(arg, "--no-edit"))
			edit = 0;
		else if (!strcmp(arg, "-x") || !strcmp(arg, "--i-really-want-"
				"to-expose-my-private-commit-object-name"))
			replay = 0;
		else if (strcmp(arg, "-r"))
			usage(usage_str);
	}

	arg = argv[argc - 1];
	if (get_sha1(arg, sha1))
		die ("Cannot find '%s'", arg);
	commit = (struct commit *)parse_object(sha1);
	if (!commit)
		die ("Could not find %s", sha1_to_hex(sha1));
	if (commit->object.type == OBJ_TAG) {
		commit = (struct commit *)
			deref_tag((struct object *)commit, arg, strlen(arg));
		needed_deref = 1;
	}
	if (commit->object.type != OBJ_COMMIT)
		die ("'%s' does not point to a commit", arg);
}

static char *get_oneline(const char *message)
{
	char *result;
	const char *p = message, *abbrev, *eol;
	int abbrev_len, oneline_len;

	if (!p)
		die ("Could not read commit message of %s",
				sha1_to_hex(commit->object.sha1));
	while (*p && (*p != '\n' || p[1] != '\n'))
		p++;

	if (*p) {
		p += 2;
		for (eol = p + 1; *eol && *eol != '\n'; eol++)
			; /* do nothing */
	} else
		eol = p;
	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
	abbrev_len = strlen(abbrev);
	oneline_len = eol - p;
	result = xmalloc(abbrev_len + 5 + oneline_len);
	memcpy(result, abbrev, abbrev_len);
	memcpy(result + abbrev_len, "... ", 4);
	memcpy(result + abbrev_len + 4, p, oneline_len);
	result[abbrev_len + 4 + oneline_len] = '\0';
	return result;
}

char *get_encoding(const char *message)
{
	const char *p = message, *eol;

	if (!p)
		die ("Could not read commit message of %s",
				sha1_to_hex(commit->object.sha1));
	while (*p && *p != '\n') {
		for (eol = p + 1; *eol && *eol != '\n'; eol++)
			; /* do nothing */
		if (!prefixcmp(p, "encoding ")) {
			char *result = xmalloc(eol - 8 - p);
			strlcpy(result, p + 9, eol - 8 - p);
			return result;
		}
		p = eol;
		if (*p == '\n')
			p++;
	}
	return NULL;
}

struct lock_file msg_file;
static int msg_fd;

static void add_to_msg(const char *string)
{
	int len = strlen(string);
	if (write_in_full(msg_fd, string, len) < 0)
		die ("Could not write to MERGE_MSG");
}

static void add_message_to_msg(const char *message)
{
	const char *p = message;
	while (*p && (*p != '\n' || p[1] != '\n'))
		p++;

	if (!*p)
		add_to_msg(sha1_to_hex(commit->object.sha1));

	p += 2;
	add_to_msg(p);
	return;
}

static void set_author_ident_env(const char *message)
{
	const char *p = message;
	if (!p)
		die ("Could not read commit message of %s",
				sha1_to_hex(commit->object.sha1));
	while (*p && *p != '\n') {
		const char *eol;

		for (eol = p; *eol && *eol != '\n'; eol++)
			; /* do nothing */
		if (!prefixcmp(p, "author ")) {
			char *line, *pend, *email, *timestamp;

			p += 7;
			line = xmalloc(eol + 1 - p);
			memcpy(line, p, eol - p);
			line[eol - p] = '\0';
			email = strchr(line, '<');
			if (!email)
				die ("Could not extract author email from %s",
					sha1_to_hex(commit->object.sha1));
			if (email == line)
				pend = line;
			else
				for (pend = email; pend != line + 1 &&
						isspace(pend[-1]); pend--);
					; /* do nothing */
			*pend = '\0';
			email++;
			timestamp = strchr(email, '>');
			if (!timestamp)
				die ("Could not extract author email from %s",
					sha1_to_hex(commit->object.sha1));
			*timestamp = '\0';
			for (timestamp++; *timestamp && isspace(*timestamp);
					timestamp++)
				; /* do nothing */
			setenv("GIT_AUTHOR_NAME", line, 1);
			setenv("GIT_AUTHOR_EMAIL", email, 1);
			setenv("GIT_AUTHOR_DATE", timestamp, 1);
			free(line);
			return;
		}
		p = eol;
		if (*p == '\n')
			p++;
	}
	die ("No author information found in %s",
			sha1_to_hex(commit->object.sha1));
}

static int merge_recursive(const char *base_sha1,
		const char *head_sha1, const char *head_name,
		const char *next_sha1, const char *next_name)
{
	char buffer[256];
	const char *argv[6];

	sprintf(buffer, "GITHEAD_%s", head_sha1);
	setenv(buffer, head_name, 1);
	sprintf(buffer, "GITHEAD_%s", next_sha1);
	setenv(buffer, next_name, 1);

	/*
	 * This three way merge is an interesting one.  We are at
	 * $head, and would want to apply the change between $commit
	 * and $prev on top of us (when reverting), or the change between
	 * $prev and $commit on top of us (when cherry-picking or replaying).
	 */
	argv[0] = "merge-recursive";
	argv[1] = base_sha1;
	argv[2] = "--";
	argv[3] = head_sha1;
	argv[4] = next_sha1;
	argv[5] = NULL;

	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
}

static int revert_or_cherry_pick(int argc, const char **argv)
{
	unsigned char head[20];
	struct commit *base, *next;
	int i;
	char *oneline, *reencoded_message = NULL;
	const char *message, *encoding;
	const char *defmsg = xstrdup(git_path("MERGE_MSG"));

	git_config(git_default_config);
	me = action == REVERT ? "revert" : "cherry-pick";
	setenv(GIT_REFLOG_ACTION, me, 0);
	parse_options(argc, argv);

	/* this is copied from the shell script, but it's never triggered... */
	if (action == REVERT && replay)
		die("revert is incompatible with replay");

	if (no_commit) {
		/*
		 * We do not intend to commit immediately.  We just want to
		 * merge the differences in.
		 */
		if (write_tree(head, 0, NULL))
			die ("Your index file is unmerged.");
	} else {
		struct wt_status s;

		if (get_sha1("HEAD", head))
			die ("You do not have a valid HEAD");
		wt_status_prepare(&s);
		if (s.commitable || s.workdir_dirty)
			die ("Dirty index: cannot %s", me);
		discard_cache();
	}

	if (!commit->parents)
		die ("Cannot %s a root commit", me);
	if (commit->parents->next)
		die ("Cannot %s a multi-parent commit.", me);
	if (!(message = commit->buffer))
		die ("Cannot get commit message for %s",
				sha1_to_hex(commit->object.sha1));

	/*
	 * "commit" is an existing commit.  We would want to apply
	 * the difference it introduces since its first parent "prev"
	 * on top of the current HEAD if we are cherry-pick.  Or the
	 * reverse of it if we are revert.
	 */

	msg_fd = hold_lock_file_for_update(&msg_file, defmsg, 1);

	encoding = get_encoding(message);
	if (!encoding)
		encoding = "utf-8";
	if (!git_commit_encoding)
		git_commit_encoding = "utf-8";
	if ((reencoded_message = reencode_string(message,
					git_commit_encoding, encoding)))
		message = reencoded_message;

	oneline = get_oneline(message);

	if (action == REVERT) {
		char *oneline_body = strchr(oneline, ' ');

		base = commit;
		next = commit->parents->item;
		add_to_msg("Revert \"");
		add_to_msg(oneline_body + 1);
		add_to_msg("\"\n\nThis reverts commit ");
		add_to_msg(sha1_to_hex(commit->object.sha1));
		add_to_msg(".\n");
	} else {
		base = commit->parents->item;
		next = commit;
		set_author_ident_env(message);
		add_message_to_msg(message);
		if (!replay) {
			add_to_msg("(cherry picked from commit ");
			add_to_msg(sha1_to_hex(commit->object.sha1));
			add_to_msg(")\n");
		}
	}
	if (needed_deref) {
		add_to_msg("(original 'git ");
		add_to_msg(me);
		add_to_msg("' arguments: ");
		for (i = 0; i < argc; i++) {
			if (i)
				add_to_msg(" ");
			add_to_msg(argv[i]);
		}
		add_to_msg(")\n");
	}

	if (merge_recursive(sha1_to_hex(base->object.sha1),
				sha1_to_hex(head), "HEAD",
				sha1_to_hex(next->object.sha1), oneline) ||
			write_tree(head, 0, NULL)) {
		add_to_msg("\nConflicts:\n\n");
		read_cache();
		for (i = 0; i < active_nr;) {
			struct cache_entry *ce = active_cache[i++];
			if (ce_stage(ce)) {
				add_to_msg("\t");
				add_to_msg(ce->name);
				add_to_msg("\n");
				while (i < active_nr && !strcmp(ce->name,
						active_cache[i]->name))
					i++;
			}
		}
		if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
			die ("Error wrapping up %s", defmsg);
		fprintf(stderr, "Automatic %s failed.  "
			"After resolving the conflicts,\n"
			"mark the corrected paths with 'git-add <paths>'\n"
			"and commit the result.\n", me);
		if (action == CHERRY_PICK) {
			fprintf(stderr, "When commiting, use the option "
				"'-c %s' to retain authorship and message.\n",
				find_unique_abbrev(commit->object.sha1,
					DEFAULT_ABBREV));
		}
		exit(1);
	}
	if (close(msg_fd) || commit_lock_file(&msg_file) < 0)
		die ("Error wrapping up %s", defmsg);
	fprintf(stderr, "Finished one %s.\n", me);

	/*
	 *
	 * If we are cherry-pick, and if the merge did not result in
	 * hand-editing, we will hit this commit and inherit the original
	 * author date and name.
	 * If we are revert, or if our cherry-pick results in a hand merge,
	 * we had better say that the current user is responsible for that.
	 */

	if (!no_commit) {
		if (edit)
			return execl_git_cmd("commit", "-n", NULL);
		else
			return execl_git_cmd("commit", "-n", "-F", defmsg, NULL);
	}
	if (reencoded_message)
		free(reencoded_message);

	return 0;
}

int cmd_revert(int argc, const char **argv, const char *prefix)
{
	if (isatty(0))
		edit = 1;
	action = REVERT;
	return revert_or_cherry_pick(argc, argv);
}

int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
{
	replay = 1;
	action = CHERRY_PICK;
	return revert_or_cherry_pick(argc, argv);
}