Merge branch 'tb/doc-eol-normalization'
[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 "builtin.h"
13 #include "refs.h"
14 #include "parse-options.h"
15 #include "run-command.h"
16 #include "tag.h"
17
18 static const char * const git_replace_usage[] = {
19         N_("git replace [-f] <object> <replacement>"),
20         N_("git replace [-f] --edit <object>"),
21         N_("git replace [-f] --graft <commit> [<parent>...]"),
22         N_("git replace -d <object>..."),
23         N_("git replace [--format=<format>] [-l [<pattern>]]"),
24         NULL
25 };
26
27 enum replace_format {
28         REPLACE_FORMAT_SHORT,
29         REPLACE_FORMAT_MEDIUM,
30         REPLACE_FORMAT_LONG
31 };
32
33 struct show_data {
34         const char *pattern;
35         enum replace_format format;
36 };
37
38 static int show_reference(const char *refname, const struct object_id *oid,
39                           int flag, void *cb_data)
40 {
41         struct show_data *data = cb_data;
42
43         if (!wildmatch(data->pattern, refname, 0, NULL)) {
44                 if (data->format == REPLACE_FORMAT_SHORT)
45                         printf("%s\n", refname);
46                 else if (data->format == REPLACE_FORMAT_MEDIUM)
47                         printf("%s -> %s\n", refname, oid_to_hex(oid));
48                 else { /* data->format == REPLACE_FORMAT_LONG */
49                         struct object_id object;
50                         enum object_type obj_type, repl_type;
51
52                         if (get_sha1(refname, object.hash))
53                                 return error("Failed to resolve '%s' as a valid ref.", refname);
54
55                         obj_type = sha1_object_info(object.hash, NULL);
56                         repl_type = sha1_object_info(oid->hash, NULL);
57
58                         printf("%s (%s) -> %s (%s)\n", refname, typename(obj_type),
59                                oid_to_hex(oid), typename(repl_type));
60                 }
61         }
62
63         return 0;
64 }
65
66 static int list_replace_refs(const char *pattern, const char *format)
67 {
68         struct show_data data;
69
70         if (pattern == NULL)
71                 pattern = "*";
72         data.pattern = pattern;
73
74         if (format == NULL || *format == '\0' || !strcmp(format, "short"))
75                 data.format = REPLACE_FORMAT_SHORT;
76         else if (!strcmp(format, "medium"))
77                 data.format = REPLACE_FORMAT_MEDIUM;
78         else if (!strcmp(format, "long"))
79                 data.format = REPLACE_FORMAT_LONG;
80         else
81                 die("invalid replace format '%s'\n"
82                     "valid formats are 'short', 'medium' and 'long'\n",
83                     format);
84
85         for_each_replace_ref(show_reference, (void *)&data);
86
87         return 0;
88 }
89
90 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
91                                     const struct object_id *oid);
92
93 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
94 {
95         const char **p, *full_hex;
96         struct strbuf ref = STRBUF_INIT;
97         size_t base_len;
98         int had_error = 0;
99         struct object_id oid;
100
101         strbuf_addstr(&ref, git_replace_ref_base);
102         base_len = ref.len;
103
104         for (p = argv; *p; p++) {
105                 if (get_oid(*p, &oid)) {
106                         error("Failed to resolve '%s' as a valid ref.", *p);
107                         had_error = 1;
108                         continue;
109                 }
110
111                 strbuf_setlen(&ref, base_len);
112                 strbuf_addstr(&ref, oid_to_hex(&oid));
113                 full_hex = ref.buf + base_len;
114
115                 if (read_ref(ref.buf, oid.hash)) {
116                         error("replace ref '%s' not found.", full_hex);
117                         had_error = 1;
118                         continue;
119                 }
120                 if (fn(full_hex, ref.buf, &oid))
121                         had_error = 1;
122         }
123         return had_error;
124 }
125
126 static int delete_replace_ref(const char *name, const char *ref,
127                               const struct object_id *oid)
128 {
129         if (delete_ref(NULL, ref, oid->hash, 0))
130                 return 1;
131         printf("Deleted replace ref '%s'\n", name);
132         return 0;
133 }
134
135 static void check_ref_valid(struct object_id *object,
136                             struct object_id *prev,
137                             struct strbuf *ref,
138                             int force)
139 {
140         strbuf_reset(ref);
141         strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
142         if (check_refname_format(ref->buf, 0))
143                 die("'%s' is not a valid ref name.", ref->buf);
144
145         if (read_ref(ref->buf, prev->hash))
146                 oidclr(prev);
147         else if (!force)
148                 die("replace ref '%s' already exists", ref->buf);
149 }
150
151 static int replace_object_oid(const char *object_ref,
152                                struct object_id *object,
153                                const char *replace_ref,
154                                struct object_id *repl,
155                                int force)
156 {
157         struct object_id prev;
158         enum object_type obj_type, repl_type;
159         struct strbuf ref = STRBUF_INIT;
160         struct ref_transaction *transaction;
161         struct strbuf err = STRBUF_INIT;
162
163         obj_type = sha1_object_info(object->hash, NULL);
164         repl_type = sha1_object_info(repl->hash, NULL);
165         if (!force && obj_type != repl_type)
166                 die("Objects must be of the same type.\n"
167                     "'%s' points to a replaced object of type '%s'\n"
168                     "while '%s' points to a replacement object of type '%s'.",
169                     object_ref, typename(obj_type),
170                     replace_ref, typename(repl_type));
171
172         check_ref_valid(object, &prev, &ref, force);
173
174         transaction = ref_transaction_begin(&err);
175         if (!transaction ||
176             ref_transaction_update(transaction, ref.buf, repl->hash, prev.hash,
177                                    0, NULL, &err) ||
178             ref_transaction_commit(transaction, &err))
179                 die("%s", err.buf);
180
181         ref_transaction_free(transaction);
182         strbuf_release(&ref);
183         return 0;
184 }
185
186 static int replace_object(const char *object_ref, const char *replace_ref, int force)
187 {
188         struct object_id object, repl;
189
190         if (get_oid(object_ref, &object))
191                 die("Failed to resolve '%s' as a valid ref.", object_ref);
192         if (get_oid(replace_ref, &repl))
193                 die("Failed to resolve '%s' as a valid ref.", replace_ref);
194
195         return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
196 }
197
198 /*
199  * Write the contents of the object named by "sha1" to the file "filename".
200  * If "raw" is true, then the object's raw contents are printed according to
201  * "type". Otherwise, we pretty-print the contents for human editing.
202  */
203 static void export_object(const struct object_id *oid, enum object_type type,
204                           int raw, const char *filename)
205 {
206         struct child_process cmd = CHILD_PROCESS_INIT;
207         int fd;
208
209         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
210         if (fd < 0)
211                 die_errno("unable to open %s for writing", filename);
212
213         argv_array_push(&cmd.args, "--no-replace-objects");
214         argv_array_push(&cmd.args, "cat-file");
215         if (raw)
216                 argv_array_push(&cmd.args, typename(type));
217         else
218                 argv_array_push(&cmd.args, "-p");
219         argv_array_push(&cmd.args, oid_to_hex(oid));
220         cmd.git_cmd = 1;
221         cmd.out = fd;
222
223         if (run_command(&cmd))
224                 die("cat-file reported failure");
225 }
226
227 /*
228  * Read a previously-exported (and possibly edited) object back from "filename",
229  * interpreting it as "type", and writing the result to the object database.
230  * The sha1 of the written object is returned via sha1.
231  */
232 static void import_object(struct object_id *oid, enum object_type type,
233                           int raw, const char *filename)
234 {
235         int fd;
236
237         fd = open(filename, O_RDONLY);
238         if (fd < 0)
239                 die_errno("unable to open %s for reading", filename);
240
241         if (!raw && type == OBJ_TREE) {
242                 const char *argv[] = { "mktree", NULL };
243                 struct child_process cmd = CHILD_PROCESS_INIT;
244                 struct strbuf result = STRBUF_INIT;
245
246                 cmd.argv = argv;
247                 cmd.git_cmd = 1;
248                 cmd.in = fd;
249                 cmd.out = -1;
250
251                 if (start_command(&cmd))
252                         die("unable to spawn mktree");
253
254                 if (strbuf_read(&result, cmd.out, 41) < 0)
255                         die_errno("unable to read from mktree");
256                 close(cmd.out);
257
258                 if (finish_command(&cmd))
259                         die("mktree reported failure");
260                 if (get_oid_hex(result.buf, oid) < 0)
261                         die("mktree did not return an object name");
262
263                 strbuf_release(&result);
264         } else {
265                 struct stat st;
266                 int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
267
268                 if (fstat(fd, &st) < 0)
269                         die_errno("unable to fstat %s", filename);
270                 if (index_fd(oid->hash, fd, &st, type, NULL, flags) < 0)
271                         die("unable to write object to database");
272                 /* index_fd close()s fd for us */
273         }
274
275         /*
276          * No need to close(fd) here; both run-command and index-fd
277          * will have done it for us.
278          */
279 }
280
281 static int edit_and_replace(const char *object_ref, int force, int raw)
282 {
283         char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
284         enum object_type type;
285         struct object_id old, new, prev;
286         struct strbuf ref = STRBUF_INIT;
287
288         if (get_oid(object_ref, &old) < 0)
289                 die("Not a valid object name: '%s'", object_ref);
290
291         type = sha1_object_info(old.hash, NULL);
292         if (type < 0)
293                 die("unable to get object type for %s", oid_to_hex(&old));
294
295         check_ref_valid(&old, &prev, &ref, force);
296         strbuf_release(&ref);
297
298         export_object(&old, type, raw, tmpfile);
299         if (launch_editor(tmpfile, NULL, NULL) < 0)
300                 die("editing object file failed");
301         import_object(&new, type, raw, tmpfile);
302
303         free(tmpfile);
304
305         if (!oidcmp(&old, &new))
306                 return error("new object is the same as the old one: '%s'", oid_to_hex(&old));
307
308         return replace_object_oid(object_ref, &old, "replacement", &new, force);
309 }
310
311 static void replace_parents(struct strbuf *buf, int argc, const char **argv)
312 {
313         struct strbuf new_parents = STRBUF_INIT;
314         const char *parent_start, *parent_end;
315         int i;
316
317         /* find existing parents */
318         parent_start = buf->buf;
319         parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
320         parent_end = parent_start;
321
322         while (starts_with(parent_end, "parent "))
323                 parent_end += 48; /* "parent " + "hex sha1" + "\n" */
324
325         /* prepare new parents */
326         for (i = 0; i < argc; i++) {
327                 struct object_id oid;
328                 if (get_oid(argv[i], &oid) < 0)
329                         die(_("Not a valid object name: '%s'"), argv[i]);
330                 lookup_commit_or_die(oid.hash, argv[i]);
331                 strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
332         }
333
334         /* replace existing parents with new ones */
335         strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
336                       new_parents.buf, new_parents.len);
337
338         strbuf_release(&new_parents);
339 }
340
341 struct check_mergetag_data {
342         int argc;
343         const char **argv;
344 };
345
346 static void check_one_mergetag(struct commit *commit,
347                                struct commit_extra_header *extra,
348                                void *data)
349 {
350         struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
351         const char *ref = mergetag_data->argv[0];
352         struct object_id tag_oid;
353         struct tag *tag;
354         int i;
355
356         hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_oid.hash);
357         tag = lookup_tag(tag_oid.hash);
358         if (!tag)
359                 die(_("bad mergetag in commit '%s'"), ref);
360         if (parse_tag_buffer(tag, extra->value, extra->len))
361                 die(_("malformed mergetag in commit '%s'"), ref);
362
363         /* iterate over new parents */
364         for (i = 1; i < mergetag_data->argc; i++) {
365                 struct object_id oid;
366                 if (get_sha1(mergetag_data->argv[i], oid.hash) < 0)
367                         die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
368                 if (!oidcmp(&tag->tagged->oid, &oid))
369                         return; /* found */
370         }
371
372         die(_("original commit '%s' contains mergetag '%s' that is discarded; "
373               "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
374 }
375
376 static void check_mergetags(struct commit *commit, int argc, const char **argv)
377 {
378         struct check_mergetag_data mergetag_data;
379
380         mergetag_data.argc = argc;
381         mergetag_data.argv = argv;
382         for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
383 }
384
385 static int create_graft(int argc, const char **argv, int force)
386 {
387         struct object_id old, new;
388         const char *old_ref = argv[0];
389         struct commit *commit;
390         struct strbuf buf = STRBUF_INIT;
391         const char *buffer;
392         unsigned long size;
393
394         if (get_oid(old_ref, &old) < 0)
395                 die(_("Not a valid object name: '%s'"), old_ref);
396         commit = lookup_commit_or_die(old.hash, old_ref);
397
398         buffer = get_commit_buffer(commit, &size);
399         strbuf_add(&buf, buffer, size);
400         unuse_commit_buffer(commit, buffer);
401
402         replace_parents(&buf, argc - 1, &argv[1]);
403
404         if (remove_signature(&buf)) {
405                 warning(_("the original commit '%s' has a gpg signature."), old_ref);
406                 warning(_("the signature will be removed in the replacement commit!"));
407         }
408
409         check_mergetags(commit, argc, argv);
410
411         if (write_sha1_file(buf.buf, buf.len, commit_type, new.hash))
412                 die(_("could not write replacement commit for: '%s'"), old_ref);
413
414         strbuf_release(&buf);
415
416         if (!oidcmp(&old, &new))
417                 return error("new commit is the same as the old one: '%s'", oid_to_hex(&old));
418
419         return replace_object_oid(old_ref, &old, "replacement", &new, force);
420 }
421
422 int cmd_replace(int argc, const char **argv, const char *prefix)
423 {
424         int force = 0;
425         int raw = 0;
426         const char *format = NULL;
427         enum {
428                 MODE_UNSPECIFIED = 0,
429                 MODE_LIST,
430                 MODE_DELETE,
431                 MODE_EDIT,
432                 MODE_GRAFT,
433                 MODE_REPLACE
434         } cmdmode = MODE_UNSPECIFIED;
435         struct option options[] = {
436                 OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
437                 OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
438                 OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
439                 OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
440                 OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
441                 OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
442                 OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
443                 OPT_END()
444         };
445
446         check_replace_refs = 0;
447         git_config(git_default_config, NULL);
448
449         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
450
451         if (!cmdmode)
452                 cmdmode = argc ? MODE_REPLACE : MODE_LIST;
453
454         if (format && cmdmode != MODE_LIST)
455                 usage_msg_opt("--format cannot be used when not listing",
456                               git_replace_usage, options);
457
458         if (force &&
459             cmdmode != MODE_REPLACE &&
460             cmdmode != MODE_EDIT &&
461             cmdmode != MODE_GRAFT)
462                 usage_msg_opt("-f only makes sense when writing a replacement",
463                               git_replace_usage, options);
464
465         if (raw && cmdmode != MODE_EDIT)
466                 usage_msg_opt("--raw only makes sense with --edit",
467                               git_replace_usage, options);
468
469         switch (cmdmode) {
470         case MODE_DELETE:
471                 if (argc < 1)
472                         usage_msg_opt("-d needs at least one argument",
473                                       git_replace_usage, options);
474                 return for_each_replace_name(argv, delete_replace_ref);
475
476         case MODE_REPLACE:
477                 if (argc != 2)
478                         usage_msg_opt("bad number of arguments",
479                                       git_replace_usage, options);
480                 return replace_object(argv[0], argv[1], force);
481
482         case MODE_EDIT:
483                 if (argc != 1)
484                         usage_msg_opt("-e needs exactly one argument",
485                                       git_replace_usage, options);
486                 return edit_and_replace(argv[0], force, raw);
487
488         case MODE_GRAFT:
489                 if (argc < 1)
490                         usage_msg_opt("-g needs at least one argument",
491                                       git_replace_usage, options);
492                 return create_graft(argc, argv, force);
493
494         case MODE_LIST:
495                 if (argc > 1)
496                         usage_msg_opt("only one pattern can be given with -l",
497                                       git_replace_usage, options);
498                 return list_replace_refs(argv[0], format);
499
500         default:
501                 die("BUG: invalid cmdmode %d", (int)cmdmode);
502         }
503 }