935647be6bdf2ffc2b460038a10e63c2eb387a5c
[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 "tag.h"
18
19 static const char * const git_replace_usage[] = {
20 N_("git replace [-f] <object> <replacement>"),
21 N_("git replace [-f] --edit <object>"),
22 N_("git replace [-f] --graft <commit> [<parent>...]"),
23 N_("git replace -d <object>..."),
24 N_("git replace [--format=<format>] [-l [<pattern>]]"),
25 NULL
26 };
27
28 enum replace_format {
29 REPLACE_FORMAT_SHORT,
30 REPLACE_FORMAT_MEDIUM,
31 REPLACE_FORMAT_LONG
32 };
33
34 struct show_data {
35 const char *pattern;
36 enum replace_format format;
37 };
38
39 static int show_reference(const char *refname, const struct object_id *oid,
40 int flag, void *cb_data)
41 {
42 struct show_data *data = cb_data;
43
44 if (!wildmatch(data->pattern, refname, 0)) {
45 if (data->format == REPLACE_FORMAT_SHORT)
46 printf("%s\n", refname);
47 else if (data->format == REPLACE_FORMAT_MEDIUM)
48 printf("%s -> %s\n", refname, oid_to_hex(oid));
49 else { /* data->format == REPLACE_FORMAT_LONG */
50 struct object_id object;
51 enum object_type obj_type, repl_type;
52
53 if (get_oid(refname, &object))
54 return error("Failed to resolve '%s' as a valid ref.", refname);
55
56 obj_type = oid_object_info(&object, NULL);
57 repl_type = oid_object_info(oid, NULL);
58
59 printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
60 oid_to_hex(oid), type_name(repl_type));
61 }
62 }
63
64 return 0;
65 }
66
67 static int list_replace_refs(const char *pattern, const char *format)
68 {
69 struct show_data data;
70
71 if (pattern == NULL)
72 pattern = "*";
73 data.pattern = pattern;
74
75 if (format == NULL || *format == '\0' || !strcmp(format, "short"))
76 data.format = REPLACE_FORMAT_SHORT;
77 else if (!strcmp(format, "medium"))
78 data.format = REPLACE_FORMAT_MEDIUM;
79 else if (!strcmp(format, "long"))
80 data.format = REPLACE_FORMAT_LONG;
81 else
82 die("invalid replace format '%s'\n"
83 "valid formats are 'short', 'medium' and 'long'\n",
84 format);
85
86 for_each_replace_ref(show_reference, (void *)&data);
87
88 return 0;
89 }
90
91 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
92 const struct object_id *oid);
93
94 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
95 {
96 const char **p, *full_hex;
97 struct strbuf ref = STRBUF_INIT;
98 size_t base_len;
99 int had_error = 0;
100 struct object_id oid;
101
102 strbuf_addstr(&ref, git_replace_ref_base);
103 base_len = ref.len;
104
105 for (p = argv; *p; p++) {
106 if (get_oid(*p, &oid)) {
107 error("Failed to resolve '%s' as a valid ref.", *p);
108 had_error = 1;
109 continue;
110 }
111
112 strbuf_setlen(&ref, base_len);
113 strbuf_addstr(&ref, oid_to_hex(&oid));
114 full_hex = ref.buf + base_len;
115
116 if (read_ref(ref.buf, &oid)) {
117 error("replace ref '%s' not found.", full_hex);
118 had_error = 1;
119 continue;
120 }
121 if (fn(full_hex, ref.buf, &oid))
122 had_error = 1;
123 }
124 strbuf_release(&ref);
125 return had_error;
126 }
127
128 static int delete_replace_ref(const char *name, const char *ref,
129 const struct object_id *oid)
130 {
131 if (delete_ref(NULL, ref, oid, 0))
132 return 1;
133 printf("Deleted replace ref '%s'\n", name);
134 return 0;
135 }
136
137 static void check_ref_valid(struct object_id *object,
138 struct object_id *prev,
139 struct strbuf *ref,
140 int force)
141 {
142 strbuf_reset(ref);
143 strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
144 if (check_refname_format(ref->buf, 0))
145 die("'%s' is not a valid ref name.", ref->buf);
146
147 if (read_ref(ref->buf, prev))
148 oidclr(prev);
149 else if (!force)
150 die("replace ref '%s' already exists", ref->buf);
151 }
152
153 static int replace_object_oid(const char *object_ref,
154 struct object_id *object,
155 const char *replace_ref,
156 struct object_id *repl,
157 int force)
158 {
159 struct object_id prev;
160 enum object_type obj_type, repl_type;
161 struct strbuf ref = STRBUF_INIT;
162 struct ref_transaction *transaction;
163 struct strbuf err = STRBUF_INIT;
164
165 obj_type = oid_object_info(object, NULL);
166 repl_type = oid_object_info(repl, NULL);
167 if (!force && obj_type != repl_type)
168 die("Objects must be of the same type.\n"
169 "'%s' points to a replaced object of type '%s'\n"
170 "while '%s' points to a replacement object of type '%s'.",
171 object_ref, type_name(obj_type),
172 replace_ref, type_name(repl_type));
173
174 check_ref_valid(object, &prev, &ref, force);
175
176 transaction = ref_transaction_begin(&err);
177 if (!transaction ||
178 ref_transaction_update(transaction, ref.buf, repl, &prev,
179 0, NULL, &err) ||
180 ref_transaction_commit(transaction, &err))
181 die("%s", err.buf);
182
183 ref_transaction_free(transaction);
184 strbuf_release(&ref);
185 return 0;
186 }
187
188 static int replace_object(const char *object_ref, const char *replace_ref, int force)
189 {
190 struct object_id object, repl;
191
192 if (get_oid(object_ref, &object))
193 die("Failed to resolve '%s' as a valid ref.", object_ref);
194 if (get_oid(replace_ref, &repl))
195 die("Failed to resolve '%s' as a valid ref.", replace_ref);
196
197 return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
198 }
199
200 /*
201 * Write the contents of the object named by "sha1" to the file "filename".
202 * If "raw" is true, then the object's raw contents are printed according to
203 * "type". Otherwise, we pretty-print the contents for human editing.
204 */
205 static void export_object(const struct object_id *oid, enum object_type type,
206 int raw, const char *filename)
207 {
208 struct child_process cmd = CHILD_PROCESS_INIT;
209 int fd;
210
211 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
212 if (fd < 0)
213 die_errno("unable to open %s for writing", filename);
214
215 argv_array_push(&cmd.args, "--no-replace-objects");
216 argv_array_push(&cmd.args, "cat-file");
217 if (raw)
218 argv_array_push(&cmd.args, type_name(type));
219 else
220 argv_array_push(&cmd.args, "-p");
221 argv_array_push(&cmd.args, oid_to_hex(oid));
222 cmd.git_cmd = 1;
223 cmd.out = fd;
224
225 if (run_command(&cmd))
226 die("cat-file reported failure");
227 }
228
229 /*
230 * Read a previously-exported (and possibly edited) object back from "filename",
231 * interpreting it as "type", and writing the result to the object database.
232 * The sha1 of the written object is returned via sha1.
233 */
234 static void import_object(struct object_id *oid, enum object_type type,
235 int raw, const char *filename)
236 {
237 int fd;
238
239 fd = open(filename, O_RDONLY);
240 if (fd < 0)
241 die_errno("unable to open %s for reading", filename);
242
243 if (!raw && type == OBJ_TREE) {
244 const char *argv[] = { "mktree", NULL };
245 struct child_process cmd = CHILD_PROCESS_INIT;
246 struct strbuf result = STRBUF_INIT;
247
248 cmd.argv = argv;
249 cmd.git_cmd = 1;
250 cmd.in = fd;
251 cmd.out = -1;
252
253 if (start_command(&cmd))
254 die("unable to spawn mktree");
255
256 if (strbuf_read(&result, cmd.out, 41) < 0)
257 die_errno("unable to read from mktree");
258 close(cmd.out);
259
260 if (finish_command(&cmd))
261 die("mktree reported failure");
262 if (get_oid_hex(result.buf, oid) < 0)
263 die("mktree did not return an object name");
264
265 strbuf_release(&result);
266 } else {
267 struct stat st;
268 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
269
270 if (fstat(fd, &st) < 0)
271 die_errno("unable to fstat %s", filename);
272 if (index_fd(oid, fd, &st, type, NULL, flags) < 0)
273 die("unable to write object to database");
274 /* index_fd close()s fd for us */
275 }
276
277 /*
278 * No need to close(fd) here; both run-command and index-fd
279 * will have done it for us.
280 */
281 }
282
283 static int edit_and_replace(const char *object_ref, int force, int raw)
284 {
285 char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
286 enum object_type type;
287 struct object_id old_oid, new_oid, prev;
288 struct strbuf ref = STRBUF_INIT;
289
290 if (get_oid(object_ref, &old_oid) < 0)
291 die("Not a valid object name: '%s'", object_ref);
292
293 type = oid_object_info(&old_oid, NULL);
294 if (type < 0)
295 die("unable to get object type for %s", oid_to_hex(&old_oid));
296
297 check_ref_valid(&old_oid, &prev, &ref, force);
298 strbuf_release(&ref);
299
300 export_object(&old_oid, type, raw, tmpfile);
301 if (launch_editor(tmpfile, NULL, NULL) < 0)
302 die("editing object file failed");
303 import_object(&new_oid, type, raw, tmpfile);
304
305 free(tmpfile);
306
307 if (!oidcmp(&old_oid, &new_oid))
308 return error("new object is the same as the old one: '%s'", oid_to_hex(&old_oid));
309
310 return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
311 }
312
313 static void replace_parents(struct strbuf *buf, int argc, const char **argv)
314 {
315 struct strbuf new_parents = STRBUF_INIT;
316 const char *parent_start, *parent_end;
317 int i;
318
319 /* find existing parents */
320 parent_start = buf->buf;
321 parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
322 parent_end = parent_start;
323
324 while (starts_with(parent_end, "parent "))
325 parent_end += 48; /* "parent " + "hex sha1" + "\n" */
326
327 /* prepare new parents */
328 for (i = 0; i < argc; i++) {
329 struct object_id oid;
330 if (get_oid(argv[i], &oid) < 0)
331 die(_("Not a valid object name: '%s'"), argv[i]);
332 lookup_commit_or_die(&oid, argv[i]);
333 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
334 }
335
336 /* replace existing parents with new ones */
337 strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
338 new_parents.buf, new_parents.len);
339
340 strbuf_release(&new_parents);
341 }
342
343 struct check_mergetag_data {
344 int argc;
345 const char **argv;
346 };
347
348 static void check_one_mergetag(struct commit *commit,
349 struct commit_extra_header *extra,
350 void *data)
351 {
352 struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
353 const char *ref = mergetag_data->argv[0];
354 struct object_id tag_oid;
355 struct tag *tag;
356 int i;
357
358 hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
359 tag = lookup_tag(&tag_oid);
360 if (!tag)
361 die(_("bad mergetag in commit '%s'"), ref);
362 if (parse_tag_buffer(tag, extra->value, extra->len))
363 die(_("malformed mergetag in commit '%s'"), ref);
364
365 /* iterate over new parents */
366 for (i = 1; i < mergetag_data->argc; i++) {
367 struct object_id oid;
368 if (get_oid(mergetag_data->argv[i], &oid) < 0)
369 die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
370 if (!oidcmp(&tag->tagged->oid, &oid))
371 return; /* found */
372 }
373
374 die(_("original commit '%s' contains mergetag '%s' that is discarded; "
375 "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
376 }
377
378 static void check_mergetags(struct commit *commit, int argc, const char **argv)
379 {
380 struct check_mergetag_data mergetag_data;
381
382 mergetag_data.argc = argc;
383 mergetag_data.argv = argv;
384 for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
385 }
386
387 static int create_graft(int argc, const char **argv, int force)
388 {
389 struct object_id old_oid, new_oid;
390 const char *old_ref = argv[0];
391 struct commit *commit;
392 struct strbuf buf = STRBUF_INIT;
393 const char *buffer;
394 unsigned long size;
395
396 if (get_oid(old_ref, &old_oid) < 0)
397 die(_("Not a valid object name: '%s'"), old_ref);
398 commit = lookup_commit_or_die(&old_oid, old_ref);
399
400 buffer = get_commit_buffer(commit, &size);
401 strbuf_add(&buf, buffer, size);
402 unuse_commit_buffer(commit, buffer);
403
404 replace_parents(&buf, argc - 1, &argv[1]);
405
406 if (remove_signature(&buf)) {
407 warning(_("the original commit '%s' has a gpg signature."), old_ref);
408 warning(_("the signature will be removed in the replacement commit!"));
409 }
410
411 check_mergetags(commit, argc, argv);
412
413 if (write_object_file(buf.buf, buf.len, commit_type, &new_oid))
414 die(_("could not write replacement commit for: '%s'"), old_ref);
415
416 strbuf_release(&buf);
417
418 if (!oidcmp(&old_oid, &new_oid))
419 return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
420
421 return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
422 }
423
424 int cmd_replace(int argc, const char **argv, const char *prefix)
425 {
426 int force = 0;
427 int raw = 0;
428 const char *format = NULL;
429 enum {
430 MODE_UNSPECIFIED = 0,
431 MODE_LIST,
432 MODE_DELETE,
433 MODE_EDIT,
434 MODE_GRAFT,
435 MODE_REPLACE
436 } cmdmode = MODE_UNSPECIFIED;
437 struct option options[] = {
438 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
439 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
440 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
441 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
442 OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
443 PARSE_OPT_NOCOMPLETE),
444 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
445 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
446 OPT_END()
447 };
448
449 check_replace_refs = 0;
450 git_config(git_default_config, NULL);
451
452 argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
453
454 if (!cmdmode)
455 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
456
457 if (format && cmdmode != MODE_LIST)
458 usage_msg_opt("--format cannot be used when not listing",
459 git_replace_usage, options);
460
461 if (force &&
462 cmdmode != MODE_REPLACE &&
463 cmdmode != MODE_EDIT &&
464 cmdmode != MODE_GRAFT)
465 usage_msg_opt("-f only makes sense when writing a replacement",
466 git_replace_usage, options);
467
468 if (raw && cmdmode != MODE_EDIT)
469 usage_msg_opt("--raw only makes sense with --edit",
470 git_replace_usage, options);
471
472 switch (cmdmode) {
473 case MODE_DELETE:
474 if (argc < 1)
475 usage_msg_opt("-d needs at least one argument",
476 git_replace_usage, options);
477 return for_each_replace_name(argv, delete_replace_ref);
478
479 case MODE_REPLACE:
480 if (argc != 2)
481 usage_msg_opt("bad number of arguments",
482 git_replace_usage, options);
483 return replace_object(argv[0], argv[1], force);
484
485 case MODE_EDIT:
486 if (argc != 1)
487 usage_msg_opt("-e needs exactly one argument",
488 git_replace_usage, options);
489 return edit_and_replace(argv[0], force, raw);
490
491 case MODE_GRAFT:
492 if (argc < 1)
493 usage_msg_opt("-g needs at least one argument",
494 git_replace_usage, options);
495 return create_graft(argc, argv, force);
496
497 case MODE_LIST:
498 if (argc > 1)
499 usage_msg_opt("only one pattern can be given with -l",
500 git_replace_usage, options);
501 return list_replace_refs(argv[0], format);
502
503 default:
504 die("BUG: invalid cmdmode %d", (int)cmdmode);
505 }
506 }