builtin rebase: support --force-rebase
[git/git.git] / builtin / rebase.c
CommitLineData
55071ea2
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1/*
2 * "git rebase" builtin command
3 *
4 * Copyright (c) 2018 Pratik Karki
5 */
6
7#include "builtin.h"
8#include "run-command.h"
9#include "exec-cmd.h"
10#include "argv-array.h"
11#include "dir.h"
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12#include "packfile.h"
13#include "refs.h"
14#include "quote.h"
15#include "config.h"
16#include "cache-tree.h"
17#include "unpack-trees.h"
18#include "lockfile.h"
f28d40d3 19#include "parse-options.h"
075bc852 20#include "commit.h"
bff014da 21#include "diff.h"
e0333e5c 22#include "wt-status.h"
9a48a615 23#include "revision.h"
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24
25static char const * const builtin_rebase_usage[] = {
26 N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
27 "[<upstream>] [<branch>]"),
28 N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
29 "--root [<branch>]"),
30 N_("git rebase --continue | --abort | --skip | --edit-todo"),
31 NULL
32};
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33
34static GIT_PATH_FUNC(apply_dir, "rebase-apply")
35static GIT_PATH_FUNC(merge_dir, "rebase-merge")
36
37enum rebase_type {
38 REBASE_UNSPECIFIED = -1,
39 REBASE_AM,
40 REBASE_MERGE,
41 REBASE_INTERACTIVE,
42 REBASE_PRESERVE_MERGES
43};
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44
45static int use_builtin_rebase(void)
46{
47 struct child_process cp = CHILD_PROCESS_INIT;
48 struct strbuf out = STRBUF_INIT;
49 int ret;
50
51 argv_array_pushl(&cp.args,
52 "config", "--bool", "rebase.usebuiltin", NULL);
53 cp.git_cmd = 1;
54 if (capture_command(&cp, &out, 6)) {
55 strbuf_release(&out);
56 return 0;
57 }
58
59 strbuf_trim(&out);
60 ret = !strcmp("true", out.buf);
61 strbuf_release(&out);
62 return ret;
63}
64
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65static int apply_autostash(void)
66{
67 warning("TODO");
68 return 0;
69}
70
71struct rebase_options {
72 enum rebase_type type;
73 const char *state_dir;
74 struct commit *upstream;
75 const char *upstream_name;
06e4775a 76 const char *upstream_arg;
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77 char *head_name;
78 struct object_id orig_head;
79 struct commit *onto;
80 const char *onto_name;
81 const char *revisions;
82 int root;
83 struct commit *restrict_revision;
84 int dont_finish_rebase;
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85 enum {
86 REBASE_NO_QUIET = 1<<0,
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87 REBASE_VERBOSE = 1<<1,
88 REBASE_DIFFSTAT = 1<<2,
1ed9c14f 89 REBASE_FORCE = 1<<3,
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90 } flags;
91 struct strbuf git_am_opt;
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92};
93
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94static int is_interactive(struct rebase_options *opts)
95{
96 return opts->type == REBASE_INTERACTIVE ||
97 opts->type == REBASE_PRESERVE_MERGES;
98}
99
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100/* Returns the filename prefixed by the state_dir */
101static const char *state_dir_path(const char *filename, struct rebase_options *opts)
102{
103 static struct strbuf path = STRBUF_INIT;
104 static size_t prefix_len;
105
106 if (!prefix_len) {
107 strbuf_addf(&path, "%s/", opts->state_dir);
108 prefix_len = path.len;
109 }
110
111 strbuf_setlen(&path, prefix_len);
112 strbuf_addstr(&path, filename);
113 return path.buf;
114}
115
116static int finish_rebase(struct rebase_options *opts)
117{
118 struct strbuf dir = STRBUF_INIT;
119 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
120
121 delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
122 apply_autostash();
123 close_all_packs(the_repository->objects);
124 /*
125 * We ignore errors in 'gc --auto', since the
126 * user should see them.
127 */
128 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
129 strbuf_addstr(&dir, opts->state_dir);
130 remove_dir_recursively(&dir, 0);
131 strbuf_release(&dir);
132
133 return 0;
134}
135
136static struct commit *peel_committish(const char *name)
137{
138 struct object *obj;
139 struct object_id oid;
140
141 if (get_oid(name, &oid))
142 return NULL;
143 obj = parse_object(the_repository, &oid);
144 return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
145}
146
147static void add_var(struct strbuf *buf, const char *name, const char *value)
148{
149 if (!value)
150 strbuf_addf(buf, "unset %s; ", name);
151 else {
152 strbuf_addf(buf, "%s=", name);
153 sq_quote_buf(buf, value);
154 strbuf_addstr(buf, "; ");
155 }
156}
157
158static int run_specific_rebase(struct rebase_options *opts)
159{
160 const char *argv[] = { NULL, NULL };
161 struct strbuf script_snippet = STRBUF_INIT;
162 int status;
163 const char *backend, *backend_func;
164
165 add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
166 add_var(&script_snippet, "state_dir", opts->state_dir);
167
168 add_var(&script_snippet, "upstream_name", opts->upstream_name);
169 add_var(&script_snippet, "upstream",
170 oid_to_hex(&opts->upstream->object.oid));
171 add_var(&script_snippet, "head_name", opts->head_name);
172 add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
173 add_var(&script_snippet, "onto", oid_to_hex(&opts->onto->object.oid));
174 add_var(&script_snippet, "onto_name", opts->onto_name);
175 add_var(&script_snippet, "revisions", opts->revisions);
176 add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
177 oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
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178 add_var(&script_snippet, "GIT_QUIET",
179 opts->flags & REBASE_NO_QUIET ? "" : "t");
180 add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
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181 add_var(&script_snippet, "verbose",
182 opts->flags & REBASE_VERBOSE ? "t" : "");
183 add_var(&script_snippet, "diffstat",
184 opts->flags & REBASE_DIFFSTAT ? "t" : "");
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185 add_var(&script_snippet, "force_rebase",
186 opts->flags & REBASE_FORCE ? "t" : "");
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187
188 switch (opts->type) {
189 case REBASE_AM:
190 backend = "git-rebase--am";
191 backend_func = "git_rebase__am";
192 break;
193 case REBASE_INTERACTIVE:
194 backend = "git-rebase--interactive";
195 backend_func = "git_rebase__interactive";
196 break;
197 case REBASE_MERGE:
198 backend = "git-rebase--merge";
199 backend_func = "git_rebase__merge";
200 break;
201 case REBASE_PRESERVE_MERGES:
202 backend = "git-rebase--preserve-merges";
203 backend_func = "git_rebase__preserve_merges";
204 break;
205 default:
206 BUG("Unhandled rebase type %d", opts->type);
207 break;
208 }
209
210 strbuf_addf(&script_snippet,
211 ". git-sh-setup && . git-rebase--common &&"
212 " . %s && %s", backend, backend_func);
213 argv[0] = script_snippet.buf;
214
215 status = run_command_v_opt(argv, RUN_USING_SHELL);
216 if (opts->dont_finish_rebase)
217 ; /* do nothing */
218 else if (status == 0) {
219 if (!file_exists(state_dir_path("stopped-sha", opts)))
220 finish_rebase(opts);
221 } else if (status == 2) {
222 struct strbuf dir = STRBUF_INIT;
223
224 apply_autostash();
225 strbuf_addstr(&dir, opts->state_dir);
226 remove_dir_recursively(&dir, 0);
227 strbuf_release(&dir);
228 die("Nothing to do");
229 }
230
231 strbuf_release(&script_snippet);
232
233 return status ? -1 : 0;
234}
235
236#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
237
238static int reset_head(struct object_id *oid, const char *action,
239 const char *switch_to_branch, int detach_head)
240{
241 struct object_id head_oid;
242 struct tree_desc desc;
243 struct lock_file lock = LOCK_INIT;
244 struct unpack_trees_options unpack_tree_opts;
245 struct tree *tree;
246 const char *reflog_action;
247 struct strbuf msg = STRBUF_INIT;
248 size_t prefix_len;
249 struct object_id *orig = NULL, oid_orig,
250 *old_orig = NULL, oid_old_orig;
251 int ret = 0;
252
253 if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
254 return -1;
255
256 if (!oid) {
257 if (get_oid("HEAD", &head_oid)) {
258 rollback_lock_file(&lock);
259 return error(_("could not determine HEAD revision"));
260 }
261 oid = &head_oid;
262 }
263
264 memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
265 setup_unpack_trees_porcelain(&unpack_tree_opts, action);
266 unpack_tree_opts.head_idx = 1;
267 unpack_tree_opts.src_index = the_repository->index;
268 unpack_tree_opts.dst_index = the_repository->index;
269 unpack_tree_opts.fn = oneway_merge;
270 unpack_tree_opts.update = 1;
271 unpack_tree_opts.merge = 1;
272 if (!detach_head)
273 unpack_tree_opts.reset = 1;
274
275 if (read_index_unmerged(the_repository->index) < 0) {
276 rollback_lock_file(&lock);
277 return error(_("could not read index"));
278 }
279
280 if (!fill_tree_descriptor(&desc, oid)) {
281 error(_("failed to find tree of %s"), oid_to_hex(oid));
282 rollback_lock_file(&lock);
283 free((void *)desc.buffer);
284 return -1;
285 }
286
287 if (unpack_trees(1, &desc, &unpack_tree_opts)) {
288 rollback_lock_file(&lock);
289 free((void *)desc.buffer);
290 return -1;
291 }
292
293 tree = parse_tree_indirect(oid);
294 prime_cache_tree(the_repository->index, tree);
295
296 if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
297 ret = error(_("could not write index"));
298 free((void *)desc.buffer);
299
300 if (ret)
301 return ret;
302
303 reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
304 strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
305 prefix_len = msg.len;
306
307 if (!get_oid("ORIG_HEAD", &oid_old_orig))
308 old_orig = &oid_old_orig;
309 if (!get_oid("HEAD", &oid_orig)) {
310 orig = &oid_orig;
311 strbuf_addstr(&msg, "updating ORIG_HEAD");
312 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
313 UPDATE_REFS_MSG_ON_ERR);
314 } else if (old_orig)
315 delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
316 strbuf_setlen(&msg, prefix_len);
317 strbuf_addstr(&msg, "updating HEAD");
318 if (!switch_to_branch)
319 ret = update_ref(msg.buf, "HEAD", oid, orig, REF_NO_DEREF,
320 UPDATE_REFS_MSG_ON_ERR);
321 else {
322 ret = create_symref("HEAD", switch_to_branch, msg.buf);
323 if (!ret)
324 ret = update_ref(msg.buf, "HEAD", oid, NULL, 0,
325 UPDATE_REFS_MSG_ON_ERR);
326 }
327
328 strbuf_release(&msg);
329 return ret;
330}
331
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332static int rebase_config(const char *var, const char *value, void *data)
333{
334 struct rebase_options *opts = data;
335
336 if (!strcmp(var, "rebase.stat")) {
337 if (git_config_bool(var, value))
338 opts->flags |= REBASE_DIFFSTAT;
339 else
340 opts->flags &= !REBASE_DIFFSTAT;
341 return 0;
342 }
343
344 return git_default_config(var, value, data);
345}
346
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347/*
348 * Determines whether the commits in from..to are linear, i.e. contain
349 * no merge commits. This function *expects* `from` to be an ancestor of
350 * `to`.
351 */
352static int is_linear_history(struct commit *from, struct commit *to)
353{
354 while (to && to != from) {
355 parse_commit(to);
356 if (!to->parents)
357 return 1;
358 if (to->parents->next)
359 return 0;
360 to = to->parents->item;
361 }
362 return 1;
363}
364
365static int can_fast_forward(struct commit *onto, struct object_id *head_oid,
366 struct object_id *merge_base)
367{
368 struct commit *head = lookup_commit(the_repository, head_oid);
369 struct commit_list *merge_bases;
370 int res;
371
372 if (!head)
373 return 0;
374
375 merge_bases = get_merge_bases(onto, head);
376 if (merge_bases && !merge_bases->next) {
377 oidcpy(merge_base, &merge_bases->item->object.oid);
378 res = !oidcmp(merge_base, &onto->object.oid);
379 } else {
380 oidcpy(merge_base, &null_oid);
381 res = 0;
382 }
383 free_commit_list(merge_bases);
384 return res && is_linear_history(onto, head);
385}
386
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387int cmd_rebase(int argc, const char **argv, const char *prefix)
388{
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389 struct rebase_options options = {
390 .type = REBASE_UNSPECIFIED,
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391 .flags = REBASE_NO_QUIET,
392 .git_am_opt = STRBUF_INIT,
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393 };
394 const char *branch_name;
395 int ret, flags;
06e4775a 396 int ok_to_skip_pre_rebase = 0;
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397 struct strbuf msg = STRBUF_INIT;
398 struct strbuf revisions = STRBUF_INIT;
075bc852 399 struct object_id merge_base;
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400 struct option builtin_rebase_options[] = {
401 OPT_STRING(0, "onto", &options.onto_name,
402 N_("revision"),
403 N_("rebase onto given branch instead of upstream")),
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404 OPT_BOOL(0, "no-verify", &ok_to_skip_pre_rebase,
405 N_("allow pre-rebase hook to run")),
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406 OPT_NEGBIT('q', "quiet", &options.flags,
407 N_("be quiet. implies --no-stat"),
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408 REBASE_NO_QUIET| REBASE_VERBOSE | REBASE_DIFFSTAT),
409 OPT_BIT('v', "verbose", &options.flags,
410 N_("display a diffstat of what changed upstream"),
411 REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
412 {OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
413 N_("do not show diffstat of what changed upstream"),
414 PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
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415 OPT_BIT('f', "force-rebase", &options.flags,
416 N_("cherry-pick all commits, even if unchanged"),
417 REBASE_FORCE),
418 OPT_BIT(0, "no-ff", &options.flags,
419 N_("cherry-pick all commits, even if unchanged"),
420 REBASE_FORCE),
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421 OPT_END(),
422 };
ac7f467f 423
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424 /*
425 * NEEDSWORK: Once the builtin rebase has been tested enough
426 * and git-legacy-rebase.sh is retired to contrib/, this preamble
427 * can be removed.
428 */
429
430 if (!use_builtin_rebase()) {
431 const char *path = mkpath("%s/git-legacy-rebase",
432 git_exec_path());
433
434 if (sane_execvp(path, (char **)argv) < 0)
435 die_errno(_("could not exec %s"), path);
436 else
437 BUG("sane_execvp() returned???");
438 }
439
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440 if (argc == 2 && !strcmp(argv[1], "-h"))
441 usage_with_options(builtin_rebase_usage,
442 builtin_rebase_options);
443
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444 prefix = setup_git_directory();
445 trace_repo_setup(prefix);
446 setup_work_tree();
447
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448 git_config(rebase_config, &options);
449
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450 argc = parse_options(argc, argv, prefix,
451 builtin_rebase_options,
452 builtin_rebase_usage, 0);
453
454 if (argc > 2)
455 usage_with_options(builtin_rebase_usage,
456 builtin_rebase_options);
ac7f467f 457
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458 if (!(options.flags & REBASE_NO_QUIET))
459 strbuf_addstr(&options.git_am_opt, " -q");
460
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461 switch (options.type) {
462 case REBASE_MERGE:
463 case REBASE_INTERACTIVE:
464 case REBASE_PRESERVE_MERGES:
465 options.state_dir = merge_dir();
466 break;
467 case REBASE_AM:
468 options.state_dir = apply_dir();
469 break;
470 default:
471 /* the default rebase backend is `--am` */
472 options.type = REBASE_AM;
473 options.state_dir = apply_dir();
474 break;
475 }
476
477 if (!options.root) {
f28d40d3 478 if (argc < 1)
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479 die("TODO: handle @{upstream}");
480 else {
f28d40d3 481 options.upstream_name = argv[0];
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482 argc--;
483 argv++;
484 if (!strcmp(options.upstream_name, "-"))
485 options.upstream_name = "@{-1}";
486 }
487 options.upstream = peel_committish(options.upstream_name);
488 if (!options.upstream)
489 die(_("invalid upstream '%s'"), options.upstream_name);
06e4775a 490 options.upstream_arg = options.upstream_name;
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491 } else
492 die("TODO: upstream for --root");
493
494 /* Make sure the branch to rebase onto is valid. */
495 if (!options.onto_name)
496 options.onto_name = options.upstream_name;
497 if (strstr(options.onto_name, "...")) {
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498 if (get_oid_mb(options.onto_name, &merge_base) < 0)
499 die(_("'%s': need exactly one merge base"),
500 options.onto_name);
501 options.onto = lookup_commit_or_die(&merge_base,
502 options.onto_name);
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503 } else {
504 options.onto = peel_committish(options.onto_name);
505 if (!options.onto)
506 die(_("Does not point to a valid commit '%s'"),
507 options.onto_name);
508 }
509
510 /*
511 * If the branch to rebase is given, that is the branch we will rebase
512 * branch_name -- branch/commit being rebased, or
513 * HEAD (already detached)
514 * orig_head -- commit object name of tip of the branch before rebasing
515 * head_name -- refs/heads/<that-branch> or "detached HEAD"
516 */
f28d40d3 517 if (argc > 0)
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518 die("TODO: handle switch_to");
519 else {
520 /* Do not need to switch branches, we are already on it. */
521 options.head_name =
522 xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
523 &flags));
524 if (!options.head_name)
525 die(_("No such ref: %s"), "HEAD");
526 if (flags & REF_ISSYMREF) {
527 if (!skip_prefix(options.head_name,
528 "refs/heads/", &branch_name))
529 branch_name = options.head_name;
530
531 } else {
532 options.head_name = xstrdup("detached HEAD");
533 branch_name = "HEAD";
534 }
535 if (get_oid("HEAD", &options.orig_head))
536 die(_("Could not resolve HEAD to a revision"));
537 }
538
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539 if (read_index(the_repository->index) < 0)
540 die(_("could not read index"));
541
542 if (require_clean_work_tree("rebase",
543 _("Please commit or stash them."), 1, 1)) {
544 ret = 1;
545 goto cleanup;
546 }
547
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548 /*
549 * Now we are rebasing commits upstream..orig_head (or with --root,
550 * everything leading up to orig_head) on top of onto.
551 */
552
553 /*
554 * Check if we are already based on onto with linear history,
555 * but this should be done only when upstream and onto are the same
556 * and if this is not an interactive rebase.
557 */
558 if (can_fast_forward(options.onto, &options.orig_head, &merge_base) &&
559 !is_interactive(&options) && !options.restrict_revision &&
560 !oidcmp(&options.upstream->object.oid, &options.onto->object.oid)) {
561 int flag;
562
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563 if (!(options.flags & REBASE_FORCE)) {
564 if (!(options.flags & REBASE_NO_QUIET))
565 ; /* be quiet */
566 else if (!strcmp(branch_name, "HEAD") &&
567 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
568 puts(_("HEAD is up to date."));
569 else
570 printf(_("Current branch %s is up to date.\n"),
571 branch_name);
572 ret = !!finish_rebase(&options);
573 goto cleanup;
574 } else if (!(options.flags & REBASE_NO_QUIET))
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575 ; /* be quiet */
576 else if (!strcmp(branch_name, "HEAD") &&
577 resolve_ref_unsafe("HEAD", 0, NULL, &flag))
578 puts(_("HEAD is up to date, rebase forced."));
579 else
580 printf(_("Current branch %s is up to date, rebase "
581 "forced.\n"), branch_name);
582 }
583
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584 /* If a hook exists, give it a chance to interrupt*/
585 if (!ok_to_skip_pre_rebase &&
586 run_hook_le(NULL, "pre-rebase", options.upstream_arg,
587 argc ? argv[0] : NULL, NULL))
588 die(_("The pre-rebase hook refused to rebase."));
589
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590 if (options.flags & REBASE_DIFFSTAT) {
591 struct diff_options opts;
592
593 if (options.flags & REBASE_VERBOSE)
594 printf(_("Changes from %s to %s:\n"),
595 oid_to_hex(&merge_base),
596 oid_to_hex(&options.onto->object.oid));
597
598 /* We want color (if set), but no pager */
599 diff_setup(&opts);
600 opts.stat_width = -1; /* use full terminal width */
601 opts.stat_graph_width = -1; /* respect statGraphWidth config */
602 opts.output_format |=
603 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
604 opts.detect_rename = DIFF_DETECT_RENAME;
605 diff_setup_done(&opts);
606 diff_tree_oid(&merge_base, &options.onto->object.oid,
607 "", &opts);
608 diffcore_std(&opts);
609 diff_flush(&opts);
610 }
611
612 /* Detach HEAD and reset the tree */
613 if (options.flags & REBASE_NO_QUIET)
614 printf(_("First, rewinding head to replay your work on top of "
615 "it...\n"));
616
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617 strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
618 if (reset_head(&options.onto->object.oid, "checkout", NULL, 1))
619 die(_("Could not detach HEAD"));
620 strbuf_release(&msg);
621
622 strbuf_addf(&revisions, "%s..%s",
623 options.root ? oid_to_hex(&options.onto->object.oid) :
624 (options.restrict_revision ?
625 oid_to_hex(&options.restrict_revision->object.oid) :
626 oid_to_hex(&options.upstream->object.oid)),
627 oid_to_hex(&options.orig_head));
628
629 options.revisions = revisions.buf;
630
631 ret = !!run_specific_rebase(&options);
632
e0333e5c 633cleanup:
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634 strbuf_release(&revisions);
635 free(options.head_name);
636 return ret;
55071ea2 637}