237ea656cfb6297da175c3d4681edb748883ed55
[git/git.git] / builtin / replace.c
1 /*
2 * Builtin "git replace"
3 *
4 * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
5 *
6 * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
7 * and Carlos Rica <jasampler@gmail.com> that was itself based on
8 * git-tag.sh and mktag.c by Linus Torvalds.
9 */
10
11 #include "cache.h"
12 #include "config.h"
13 #include "builtin.h"
14 #include "refs.h"
15 #include "parse-options.h"
16 #include "run-command.h"
17 #include "object-store.h"
18 #include "repository.h"
19 #include "tag.h"
20
21 static const char * const git_replace_usage[] = {
22 N_("git replace [-f] <object> <replacement>"),
23 N_("git replace [-f] --edit <object>"),
24 N_("git replace [-f] --graft <commit> [<parent>...]"),
25 N_("git replace -d <object>..."),
26 N_("git replace [--format=<format>] [-l [<pattern>]]"),
27 NULL
28 };
29
30 enum replace_format {
31 REPLACE_FORMAT_SHORT,
32 REPLACE_FORMAT_MEDIUM,
33 REPLACE_FORMAT_LONG
34 };
35
36 struct show_data {
37 const char *pattern;
38 enum replace_format format;
39 };
40
41 static int show_reference(const char *refname, const struct object_id *oid,
42 int flag, void *cb_data)
43 {
44 struct show_data *data = cb_data;
45
46 if (!wildmatch(data->pattern, refname, 0)) {
47 if (data->format == REPLACE_FORMAT_SHORT)
48 printf("%s\n", refname);
49 else if (data->format == REPLACE_FORMAT_MEDIUM)
50 printf("%s -> %s\n", refname, oid_to_hex(oid));
51 else { /* data->format == REPLACE_FORMAT_LONG */
52 struct object_id object;
53 enum object_type obj_type, repl_type;
54
55 if (get_oid(refname, &object))
56 return error("Failed to resolve '%s' as a valid ref.", refname);
57
58 obj_type = oid_object_info(&object, NULL);
59 repl_type = oid_object_info(oid, NULL);
60
61 printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
62 oid_to_hex(oid), type_name(repl_type));
63 }
64 }
65
66 return 0;
67 }
68
69 static int list_replace_refs(const char *pattern, const char *format)
70 {
71 struct show_data data;
72
73 if (pattern == NULL)
74 pattern = "*";
75 data.pattern = pattern;
76
77 if (format == NULL || *format == '\0' || !strcmp(format, "short"))
78 data.format = REPLACE_FORMAT_SHORT;
79 else if (!strcmp(format, "medium"))
80 data.format = REPLACE_FORMAT_MEDIUM;
81 else if (!strcmp(format, "long"))
82 data.format = REPLACE_FORMAT_LONG;
83 else
84 die("invalid replace format '%s'\n"
85 "valid formats are 'short', 'medium' and 'long'\n",
86 format);
87
88 for_each_replace_ref(the_repository, show_reference, (void *)&data);
89
90 return 0;
91 }
92
93 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
94 const struct object_id *oid);
95
96 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
97 {
98 const char **p, *full_hex;
99 struct strbuf ref = STRBUF_INIT;
100 size_t base_len;
101 int had_error = 0;
102 struct object_id oid;
103
104 strbuf_addstr(&ref, git_replace_ref_base);
105 base_len = ref.len;
106
107 for (p = argv; *p; p++) {
108 if (get_oid(*p, &oid)) {
109 error("Failed to resolve '%s' as a valid ref.", *p);
110 had_error = 1;
111 continue;
112 }
113
114 strbuf_setlen(&ref, base_len);
115 strbuf_addstr(&ref, oid_to_hex(&oid));
116 full_hex = ref.buf + base_len;
117
118 if (read_ref(ref.buf, &oid)) {
119 error("replace ref '%s' not found.", full_hex);
120 had_error = 1;
121 continue;
122 }
123 if (fn(full_hex, ref.buf, &oid))
124 had_error = 1;
125 }
126 strbuf_release(&ref);
127 return had_error;
128 }
129
130 static int delete_replace_ref(const char *name, const char *ref,
131 const struct object_id *oid)
132 {
133 if (delete_ref(NULL, ref, oid, 0))
134 return 1;
135 printf("Deleted replace ref '%s'\n", name);
136 return 0;
137 }
138
139 static void check_ref_valid(struct object_id *object,
140 struct object_id *prev,
141 struct strbuf *ref,
142 int force)
143 {
144 strbuf_reset(ref);
145 strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
146 if (check_refname_format(ref->buf, 0))
147 die("'%s' is not a valid ref name.", ref->buf);
148
149 if (read_ref(ref->buf, prev))
150 oidclr(prev);
151 else if (!force)
152 die("replace ref '%s' already exists", ref->buf);
153 }
154
155 static int replace_object_oid(const char *object_ref,
156 struct object_id *object,
157 const char *replace_ref,
158 struct object_id *repl,
159 int force)
160 {
161 struct object_id prev;
162 enum object_type obj_type, repl_type;
163 struct strbuf ref = STRBUF_INIT;
164 struct ref_transaction *transaction;
165 struct strbuf err = STRBUF_INIT;
166
167 obj_type = oid_object_info(object, NULL);
168 repl_type = oid_object_info(repl, NULL);
169 if (!force && obj_type != repl_type)
170 die("Objects must be of the same type.\n"
171 "'%s' points to a replaced object of type '%s'\n"
172 "while '%s' points to a replacement object of type '%s'.",
173 object_ref, type_name(obj_type),
174 replace_ref, type_name(repl_type));
175
176 check_ref_valid(object, &prev, &ref, force);
177
178 transaction = ref_transaction_begin(&err);
179 if (!transaction ||
180 ref_transaction_update(transaction, ref.buf, repl, &prev,
181 0, NULL, &err) ||
182 ref_transaction_commit(transaction, &err))
183 die("%s", err.buf);
184
185 ref_transaction_free(transaction);
186 strbuf_release(&ref);
187 return 0;
188 }
189
190 static int replace_object(const char *object_ref, const char *replace_ref, int force)
191 {
192 struct object_id object, repl;
193
194 if (get_oid(object_ref, &object))
195 die("Failed to resolve '%s' as a valid ref.", object_ref);
196 if (get_oid(replace_ref, &repl))
197 die("Failed to resolve '%s' as a valid ref.", replace_ref);
198
199 return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
200 }
201
202 /*
203 * Write the contents of the object named by "sha1" to the file "filename".
204 * If "raw" is true, then the object's raw contents are printed according to
205 * "type". Otherwise, we pretty-print the contents for human editing.
206 */
207 static void export_object(const struct object_id *oid, enum object_type type,
208 int raw, const char *filename)
209 {
210 struct child_process cmd = CHILD_PROCESS_INIT;
211 int fd;
212
213 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
214 if (fd < 0)
215 die_errno("unable to open %s for writing", filename);
216
217 argv_array_push(&cmd.args, "--no-replace-objects");
218 argv_array_push(&cmd.args, "cat-file");
219 if (raw)
220 argv_array_push(&cmd.args, type_name(type));
221 else
222 argv_array_push(&cmd.args, "-p");
223 argv_array_push(&cmd.args, oid_to_hex(oid));
224 cmd.git_cmd = 1;
225 cmd.out = fd;
226
227 if (run_command(&cmd))
228 die("cat-file reported failure");
229 }
230
231 /*
232 * Read a previously-exported (and possibly edited) object back from "filename",
233 * interpreting it as "type", and writing the result to the object database.
234 * The sha1 of the written object is returned via sha1.
235 */
236 static void import_object(struct object_id *oid, enum object_type type,
237 int raw, const char *filename)
238 {
239 int fd;
240
241 fd = open(filename, O_RDONLY);
242 if (fd < 0)
243 die_errno("unable to open %s for reading", filename);
244
245 if (!raw && type == OBJ_TREE) {
246 const char *argv[] = { "mktree", NULL };
247 struct child_process cmd = CHILD_PROCESS_INIT;
248 struct strbuf result = STRBUF_INIT;
249
250 cmd.argv = argv;
251 cmd.git_cmd = 1;
252 cmd.in = fd;
253 cmd.out = -1;
254
255 if (start_command(&cmd))
256 die("unable to spawn mktree");
257
258 if (strbuf_read(&result, cmd.out, 41) < 0)
259 die_errno("unable to read from mktree");
260 close(cmd.out);
261
262 if (finish_command(&cmd))
263 die("mktree reported failure");
264 if (get_oid_hex(result.buf, oid) < 0)
265 die("mktree did not return an object name");
266
267 strbuf_release(&result);
268 } else {
269 struct stat st;
270 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
271
272 if (fstat(fd, &st) < 0)
273 die_errno("unable to fstat %s", filename);
274 if (index_fd(oid, fd, &st, type, NULL, flags) < 0)
275 die("unable to write object to database");
276 /* index_fd close()s fd for us */
277 }
278
279 /*
280 * No need to close(fd) here; both run-command and index-fd
281 * will have done it for us.
282 */
283 }
284
285 static int edit_and_replace(const char *object_ref, int force, int raw)
286 {
287 char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
288 enum object_type type;
289 struct object_id old_oid, new_oid, prev;
290 struct strbuf ref = STRBUF_INIT;
291
292 if (get_oid(object_ref, &old_oid) < 0)
293 die("Not a valid object name: '%s'", object_ref);
294
295 type = oid_object_info(&old_oid, NULL);
296 if (type < 0)
297 die("unable to get object type for %s", oid_to_hex(&old_oid));
298
299 check_ref_valid(&old_oid, &prev, &ref, force);
300 strbuf_release(&ref);
301
302 export_object(&old_oid, type, raw, tmpfile);
303 if (launch_editor(tmpfile, NULL, NULL) < 0)
304 die("editing object file failed");
305 import_object(&new_oid, type, raw, tmpfile);
306
307 free(tmpfile);
308
309 if (!oidcmp(&old_oid, &new_oid))
310 return error("new object is the same as the old one: '%s'", oid_to_hex(&old_oid));
311
312 return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
313 }
314
315 static void replace_parents(struct strbuf *buf, int argc, const char **argv)
316 {
317 struct strbuf new_parents = STRBUF_INIT;
318 const char *parent_start, *parent_end;
319 int i;
320
321 /* find existing parents */
322 parent_start = buf->buf;
323 parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
324 parent_end = parent_start;
325
326 while (starts_with(parent_end, "parent "))
327 parent_end += 48; /* "parent " + "hex sha1" + "\n" */
328
329 /* prepare new parents */
330 for (i = 0; i < argc; i++) {
331 struct object_id oid;
332 if (get_oid(argv[i], &oid) < 0)
333 die(_("Not a valid object name: '%s'"), argv[i]);
334 lookup_commit_or_die(&oid, argv[i]);
335 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
336 }
337
338 /* replace existing parents with new ones */
339 strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
340 new_parents.buf, new_parents.len);
341
342 strbuf_release(&new_parents);
343 }
344
345 struct check_mergetag_data {
346 int argc;
347 const char **argv;
348 };
349
350 static void check_one_mergetag(struct commit *commit,
351 struct commit_extra_header *extra,
352 void *data)
353 {
354 struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
355 const char *ref = mergetag_data->argv[0];
356 struct object_id tag_oid;
357 struct tag *tag;
358 int i;
359
360 hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
361 tag = lookup_tag(&tag_oid);
362 if (!tag)
363 die(_("bad mergetag in commit '%s'"), ref);
364 if (parse_tag_buffer(tag, extra->value, extra->len))
365 die(_("malformed mergetag in commit '%s'"), ref);
366
367 /* iterate over new parents */
368 for (i = 1; i < mergetag_data->argc; i++) {
369 struct object_id oid;
370 if (get_oid(mergetag_data->argv[i], &oid) < 0)
371 die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
372 if (!oidcmp(&tag->tagged->oid, &oid))
373 return; /* found */
374 }
375
376 die(_("original commit '%s' contains mergetag '%s' that is discarded; "
377 "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
378 }
379
380 static void check_mergetags(struct commit *commit, int argc, const char **argv)
381 {
382 struct check_mergetag_data mergetag_data;
383
384 mergetag_data.argc = argc;
385 mergetag_data.argv = argv;
386 for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
387 }
388
389 static int create_graft(int argc, const char **argv, int force)
390 {
391 struct object_id old_oid, new_oid;
392 const char *old_ref = argv[0];
393 struct commit *commit;
394 struct strbuf buf = STRBUF_INIT;
395 const char *buffer;
396 unsigned long size;
397
398 if (get_oid(old_ref, &old_oid) < 0)
399 die(_("Not a valid object name: '%s'"), old_ref);
400 commit = lookup_commit_or_die(&old_oid, old_ref);
401
402 buffer = get_commit_buffer(commit, &size);
403 strbuf_add(&buf, buffer, size);
404 unuse_commit_buffer(commit, buffer);
405
406 replace_parents(&buf, argc - 1, &argv[1]);
407
408 if (remove_signature(&buf)) {
409 warning(_("the original commit '%s' has a gpg signature."), old_ref);
410 warning(_("the signature will be removed in the replacement commit!"));
411 }
412
413 check_mergetags(commit, argc, argv);
414
415 if (write_object_file(buf.buf, buf.len, commit_type, &new_oid))
416 die(_("could not write replacement commit for: '%s'"), old_ref);
417
418 strbuf_release(&buf);
419
420 if (!oidcmp(&old_oid, &new_oid))
421 return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
422
423 return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
424 }
425
426 int cmd_replace(int argc, const char **argv, const char *prefix)
427 {
428 int force = 0;
429 int raw = 0;
430 const char *format = NULL;
431 enum {
432 MODE_UNSPECIFIED = 0,
433 MODE_LIST,
434 MODE_DELETE,
435 MODE_EDIT,
436 MODE_GRAFT,
437 MODE_REPLACE
438 } cmdmode = MODE_UNSPECIFIED;
439 struct option options[] = {
440 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
441 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
442 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
443 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
444 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
445 PARSE_OPT_NOCOMPLETE),
446 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
447 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
448 OPT_END()
449 };
450
451 check_replace_refs = 0;
452 git_config(git_default_config, NULL);
453
454 argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
455
456 if (!cmdmode)
457 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
458
459 if (format && cmdmode != MODE_LIST)
460 usage_msg_opt("--format cannot be used when not listing",
461 git_replace_usage, options);
462
463 if (force &&
464 cmdmode != MODE_REPLACE &&
465 cmdmode != MODE_EDIT &&
466 cmdmode != MODE_GRAFT)
467 usage_msg_opt("-f only makes sense when writing a replacement",
468 git_replace_usage, options);
469
470 if (raw && cmdmode != MODE_EDIT)
471 usage_msg_opt("--raw only makes sense with --edit",
472 git_replace_usage, options);
473
474 switch (cmdmode) {
475 case MODE_DELETE:
476 if (argc < 1)
477 usage_msg_opt("-d needs at least one argument",
478 git_replace_usage, options);
479 return for_each_replace_name(argv, delete_replace_ref);
480
481 case MODE_REPLACE:
482 if (argc != 2)
483 usage_msg_opt("bad number of arguments",
484 git_replace_usage, options);
485 return replace_object(argv[0], argv[1], force);
486
487 case MODE_EDIT:
488 if (argc != 1)
489 usage_msg_opt("-e needs exactly one argument",
490 git_replace_usage, options);
491 return edit_and_replace(argv[0], force, raw);
492
493 case MODE_GRAFT:
494 if (argc < 1)
495 usage_msg_opt("-g needs at least one argument",
496 git_replace_usage, options);
497 return create_graft(argc, argv, force);
498
499 case MODE_LIST:
500 if (argc > 1)
501 usage_msg_opt("only one pattern can be given with -l",
502 git_replace_usage, options);
503 return list_replace_refs(argv[0], format);
504
505 default:
506 die("BUG: invalid cmdmode %d", (int)cmdmode);
507 }
508 }