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git-commit: Allow to amend a merge commit that does not change the tree
[git/git-bigfiles.git] / merge-recursive.c
blob9a1e2f269dc5eff3b7544507a1e483948cc1254d
1 /*
2 * Recursive Merge algorithm stolen from git-merge-recursive.py by
3 * Fredrik Kuivinen.
4 * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5 */
6 #include "cache.h"
7 #include "cache-tree.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "tree-walk.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "run-command.h"
14 #include "tag.h"
15 #include "unpack-trees.h"
16 #include "path-list.h"
17 #include "xdiff-interface.h"
18 #include "interpolate.h"
19 #include "attr.h"
20
21 static int subtree_merge;
22
23 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
24 {
25 unsigned char shifted[20];
26
27 /*
28 * NEEDSWORK: this limits the recursion depth to hardcoded
29 * value '2' to avoid excessive overhead.
30 */
31 shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
32 if (!hashcmp(two->object.sha1, shifted))
33 return two;
34 return lookup_tree(shifted);
35 }
36
37 /*
38 * A virtual commit has
39 * - (const char *)commit->util set to the name, and
40 * - *(int *)commit->object.sha1 set to the virtual id.
41 */
42
43 static unsigned commit_list_count(const struct commit_list *l)
44 {
45 unsigned c = 0;
46 for (; l; l = l->next )
47 c++;
48 return c;
49 }
50
51 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
52 {
53 struct commit *commit = xcalloc(1, sizeof(struct commit));
54 static unsigned virtual_id = 1;
55 commit->tree = tree;
56 commit->util = (void*)comment;
57 *(int*)commit->object.sha1 = virtual_id++;
58 /* avoid warnings */
59 commit->object.parsed = 1;
60 return commit;
61 }
62
63 /*
64 * Since we use get_tree_entry(), which does not put the read object into
65 * the object pool, we cannot rely on a == b.
66 */
67 static int sha_eq(const unsigned char *a, const unsigned char *b)
68 {
69 if (!a && !b)
70 return 2;
71 return a && b && hashcmp(a, b) == 0;
72 }
73
74 /*
75 * Since we want to write the index eventually, we cannot reuse the index
76 * for these (temporary) data.
77 */
78 struct stage_data
79 {
80 struct
81 {
82 unsigned mode;
83 unsigned char sha[20];
84 } stages[4];
85 unsigned processed:1;
86 };
87
88 static struct path_list current_file_set = {NULL, 0, 0, 1};
89 static struct path_list current_directory_set = {NULL, 0, 0, 1};
90
91 static int call_depth = 0;
92 static int verbosity = 2;
93 static int rename_limit = -1;
94 static int buffer_output = 1;
95 static struct strbuf obuf = STRBUF_INIT;
96
97 static int show(int v)
98 {
99 return (!call_depth && verbosity >= v) || verbosity >= 5;
100 }
101
102 static void flush_output(void)
103 {
104 if (obuf.len) {
105 fputs(obuf.buf, stdout);
106 strbuf_reset(&obuf);
107 }
108 }
109
110 static void output(int v, const char *fmt, ...)
111 {
112 int len;
113 va_list ap;
114
115 if (!show(v))
116 return;
117
118 strbuf_grow(&obuf, call_depth * 2 + 2);
119 memset(obuf.buf + obuf.len, ' ', call_depth * 2);
120 strbuf_setlen(&obuf, obuf.len + call_depth * 2);
121
122 va_start(ap, fmt);
123 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
124 va_end(ap);
125
126 if (len < 0)
127 len = 0;
128 if (len >= strbuf_avail(&obuf)) {
129 strbuf_grow(&obuf, len + 2);
130 va_start(ap, fmt);
131 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
132 va_end(ap);
133 if (len >= strbuf_avail(&obuf)) {
134 die("this should not happen, your snprintf is broken");
135 }
136 }
137 strbuf_setlen(&obuf, obuf.len + len);
138 strbuf_add(&obuf, "\n", 1);
139 if (!buffer_output)
140 flush_output();
141 }
142
143 static void output_commit_title(struct commit *commit)
144 {
145 int i;
146 flush_output();
147 for (i = call_depth; i--;)
148 fputs(" ", stdout);
149 if (commit->util)
150 printf("virtual %s\n", (char *)commit->util);
151 else {
152 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
153 if (parse_commit(commit) != 0)
154 printf("(bad commit)\n");
155 else {
156 const char *s;
157 int len;
158 for (s = commit->buffer; *s; s++)
159 if (*s == '\n' && s[1] == '\n') {
160 s += 2;
161 break;
162 }
163 for (len = 0; s[len] && '\n' != s[len]; len++)
164 ; /* do nothing */
165 printf("%.*s\n", len, s);
166 }
167 }
168 }
169
170 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
171 const char *path, int stage, int refresh, int options)
172 {
173 struct cache_entry *ce;
174 ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
175 if (!ce)
176 return error("addinfo_cache failed for path '%s'", path);
177 return add_cache_entry(ce, options);
178 }
179
180 /*
181 * This is a global variable which is used in a number of places but
182 * only written to in the 'merge' function.
183 *
184 * index_only == 1 => Don't leave any non-stage 0 entries in the cache and
185 * don't update the working directory.
186 * 0 => Leave unmerged entries in the cache and update
187 * the working directory.
188 */
189 static int index_only = 0;
190
191 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
192 {
193 parse_tree(tree);
194 init_tree_desc(desc, tree->buffer, tree->size);
195 }
196
197 static int git_merge_trees(int index_only,
198 struct tree *common,
199 struct tree *head,
200 struct tree *merge)
201 {
202 int rc;
203 struct tree_desc t[3];
204 struct unpack_trees_options opts;
205
206 memset(&opts, 0, sizeof(opts));
207 if (index_only)
208 opts.index_only = 1;
209 else
210 opts.update = 1;
211 opts.merge = 1;
212 opts.head_idx = 2;
213 opts.fn = threeway_merge;
214
215 init_tree_desc_from_tree(t+0, common);
216 init_tree_desc_from_tree(t+1, head);
217 init_tree_desc_from_tree(t+2, merge);
218
219 rc = unpack_trees(3, t, &opts);
220 cache_tree_free(&active_cache_tree);
221 return rc;
222 }
223
224 static int unmerged_index(void)
225 {
226 int i;
227 for (i = 0; i < active_nr; i++) {
228 struct cache_entry *ce = active_cache[i];
229 if (ce_stage(ce))
230 return 1;
231 }
232 return 0;
233 }
234
235 static struct tree *git_write_tree(void)
236 {
237 struct tree *result = NULL;
238
239 if (unmerged_index()) {
240 int i;
241 output(0, "There are unmerged index entries:");
242 for (i = 0; i < active_nr; i++) {
243 struct cache_entry *ce = active_cache[i];
244 if (ce_stage(ce))
245 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
246 }
247 return NULL;
248 }
249
250 if (!active_cache_tree)
251 active_cache_tree = cache_tree();
252
253 if (!cache_tree_fully_valid(active_cache_tree) &&
254 cache_tree_update(active_cache_tree,
255 active_cache, active_nr, 0, 0) < 0)
256 die("error building trees");
257
258 result = lookup_tree(active_cache_tree->sha1);
259
260 return result;
261 }
262
263 static int save_files_dirs(const unsigned char *sha1,
264 const char *base, int baselen, const char *path,
265 unsigned int mode, int stage)
266 {
267 int len = strlen(path);
268 char *newpath = xmalloc(baselen + len + 1);
269 memcpy(newpath, base, baselen);
270 memcpy(newpath + baselen, path, len);
271 newpath[baselen + len] = '\0';
272
273 if (S_ISDIR(mode))
274 path_list_insert(newpath, &current_directory_set);
275 else
276 path_list_insert(newpath, &current_file_set);
277 free(newpath);
278
279 return READ_TREE_RECURSIVE;
280 }
281
282 static int get_files_dirs(struct tree *tree)
283 {
284 int n;
285 if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
286 return 0;
287 n = current_file_set.nr + current_directory_set.nr;
288 return n;
289 }
290
291 /*
292 * Returns a index_entry instance which doesn't have to correspond to
293 * a real cache entry in Git's index.
294 */
295 static struct stage_data *insert_stage_data(const char *path,
296 struct tree *o, struct tree *a, struct tree *b,
297 struct path_list *entries)
298 {
299 struct path_list_item *item;
300 struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
301 get_tree_entry(o->object.sha1, path,
302 e->stages[1].sha, &e->stages[1].mode);
303 get_tree_entry(a->object.sha1, path,
304 e->stages[2].sha, &e->stages[2].mode);
305 get_tree_entry(b->object.sha1, path,
306 e->stages[3].sha, &e->stages[3].mode);
307 item = path_list_insert(path, entries);
308 item->util = e;
309 return e;
310 }
311
312 /*
313 * Create a dictionary mapping file names to stage_data objects. The
314 * dictionary contains one entry for every path with a non-zero stage entry.
315 */
316 static struct path_list *get_unmerged(void)
317 {
318 struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
319 int i;
320
321 unmerged->strdup_paths = 1;
322
323 for (i = 0; i < active_nr; i++) {
324 struct path_list_item *item;
325 struct stage_data *e;
326 struct cache_entry *ce = active_cache[i];
327 if (!ce_stage(ce))
328 continue;
329
330 item = path_list_lookup(ce->name, unmerged);
331 if (!item) {
332 item = path_list_insert(ce->name, unmerged);
333 item->util = xcalloc(1, sizeof(struct stage_data));
334 }
335 e = item->util;
336 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
337 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
338 }
339
340 return unmerged;
341 }
342
343 struct rename
344 {
345 struct diff_filepair *pair;
346 struct stage_data *src_entry;
347 struct stage_data *dst_entry;
348 unsigned processed:1;
349 };
350
351 /*
352 * Get information of all renames which occurred between 'o_tree' and
353 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
354 * 'b_tree') to be able to associate the correct cache entries with
355 * the rename information. 'tree' is always equal to either a_tree or b_tree.
356 */
357 static struct path_list *get_renames(struct tree *tree,
358 struct tree *o_tree,
359 struct tree *a_tree,
360 struct tree *b_tree,
361 struct path_list *entries)
362 {
363 int i;
364 struct path_list *renames;
365 struct diff_options opts;
366
367 renames = xcalloc(1, sizeof(struct path_list));
368 diff_setup(&opts);
369 DIFF_OPT_SET(&opts, RECURSIVE);
370 opts.detect_rename = DIFF_DETECT_RENAME;
371 opts.rename_limit = rename_limit;
372 opts.output_format = DIFF_FORMAT_NO_OUTPUT;
373 if (diff_setup_done(&opts) < 0)
374 die("diff setup failed");
375 diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
376 diffcore_std(&opts);
377 for (i = 0; i < diff_queued_diff.nr; ++i) {
378 struct path_list_item *item;
379 struct rename *re;
380 struct diff_filepair *pair = diff_queued_diff.queue[i];
381 if (pair->status != 'R') {
382 diff_free_filepair(pair);
383 continue;
384 }
385 re = xmalloc(sizeof(*re));
386 re->processed = 0;
387 re->pair = pair;
388 item = path_list_lookup(re->pair->one->path, entries);
389 if (!item)
390 re->src_entry = insert_stage_data(re->pair->one->path,
391 o_tree, a_tree, b_tree, entries);
392 else
393 re->src_entry = item->util;
394
395 item = path_list_lookup(re->pair->two->path, entries);
396 if (!item)
397 re->dst_entry = insert_stage_data(re->pair->two->path,
398 o_tree, a_tree, b_tree, entries);
399 else
400 re->dst_entry = item->util;
401 item = path_list_insert(pair->one->path, renames);
402 item->util = re;
403 }
404 opts.output_format = DIFF_FORMAT_NO_OUTPUT;
405 diff_queued_diff.nr = 0;
406 diff_flush(&opts);
407 return renames;
408 }
409
410 static int update_stages(const char *path, struct diff_filespec *o,
411 struct diff_filespec *a, struct diff_filespec *b,
412 int clear)
413 {
414 int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
415 if (clear)
416 if (remove_file_from_cache(path))
417 return -1;
418 if (o)
419 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
420 return -1;
421 if (a)
422 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
423 return -1;
424 if (b)
425 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
426 return -1;
427 return 0;
428 }
429
430 static int remove_path(const char *name)
431 {
432 int ret;
433 char *slash, *dirs;
434
435 ret = unlink(name);
436 if (ret)
437 return ret;
438 dirs = xstrdup(name);
439 while ((slash = strrchr(name, '/'))) {
440 *slash = '\0';
441 if (rmdir(name) != 0)
442 break;
443 }
444 free(dirs);
445 return ret;
446 }
447
448 static int remove_file(int clean, const char *path, int no_wd)
449 {
450 int update_cache = index_only || clean;
451 int update_working_directory = !index_only && !no_wd;
452
453 if (update_cache) {
454 if (remove_file_from_cache(path))
455 return -1;
456 }
457 if (update_working_directory) {
458 unlink(path);
459 if (errno != ENOENT || errno != EISDIR)
460 return -1;
461 remove_path(path);
462 }
463 return 0;
464 }
465
466 static char *unique_path(const char *path, const char *branch)
467 {
468 char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
469 int suffix = 0;
470 struct stat st;
471 char *p = newpath + strlen(path);
472 strcpy(newpath, path);
473 *(p++) = '~';
474 strcpy(p, branch);
475 for (; *p; ++p)
476 if ('/' == *p)
477 *p = '_';
478 while (path_list_has_path(&current_file_set, newpath) ||
479 path_list_has_path(&current_directory_set, newpath) ||
480 lstat(newpath, &st) == 0)
481 sprintf(p, "_%d", suffix++);
482
483 path_list_insert(newpath, &current_file_set);
484 return newpath;
485 }
486
487 static int mkdir_p(const char *path, unsigned long mode)
488 {
489 /* path points to cache entries, so xstrdup before messing with it */
490 char *buf = xstrdup(path);
491 int result = safe_create_leading_directories(buf);
492 free(buf);
493 return result;
494 }
495
496 static void flush_buffer(int fd, const char *buf, unsigned long size)
497 {
498 while (size > 0) {
499 long ret = write_in_full(fd, buf, size);
500 if (ret < 0) {
501 /* Ignore epipe */
502 if (errno == EPIPE)
503 break;
504 die("merge-recursive: %s", strerror(errno));
505 } else if (!ret) {
506 die("merge-recursive: disk full?");
507 }
508 size -= ret;
509 buf += ret;
510 }
511 }
512
513 static int make_room_for_path(const char *path)
514 {
515 int status;
516 const char *msg = "failed to create path '%s'%s";
517
518 status = mkdir_p(path, 0777);
519 if (status) {
520 if (status == -3) {
521 /* something else exists */
522 error(msg, path, ": perhaps a D/F conflict?");
523 return -1;
524 }
525 die(msg, path, "");
526 }
527
528 /* Successful unlink is good.. */
529 if (!unlink(path))
530 return 0;
531 /* .. and so is no existing file */
532 if (errno == ENOENT)
533 return 0;
534 /* .. but not some other error (who really cares what?) */
535 return error(msg, path, ": perhaps a D/F conflict?");
536 }
537
538 static void update_file_flags(const unsigned char *sha,
539 unsigned mode,
540 const char *path,
541 int update_cache,
542 int update_wd)
543 {
544 if (index_only)
545 update_wd = 0;
546
547 if (update_wd) {
548 enum object_type type;
549 void *buf;
550 unsigned long size;
551
552 buf = read_sha1_file(sha, &type, &size);
553 if (!buf)
554 die("cannot read object %s '%s'", sha1_to_hex(sha), path);
555 if (type != OBJ_BLOB)
556 die("blob expected for %s '%s'", sha1_to_hex(sha), path);
557
558 if (make_room_for_path(path) < 0) {
559 update_wd = 0;
560 goto update_index;
561 }
562 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
563 int fd;
564 if (mode & 0100)
565 mode = 0777;
566 else
567 mode = 0666;
568 fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
569 if (fd < 0)
570 die("failed to open %s: %s", path, strerror(errno));
571 flush_buffer(fd, buf, size);
572 close(fd);
573 } else if (S_ISLNK(mode)) {
574 char *lnk = xmemdupz(buf, size);
575 mkdir_p(path, 0777);
576 unlink(path);
577 symlink(lnk, path);
578 free(lnk);
579 } else
580 die("do not know what to do with %06o %s '%s'",
581 mode, sha1_to_hex(sha), path);
582 }
583 update_index:
584 if (update_cache)
585 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
586 }
587
588 static void update_file(int clean,
589 const unsigned char *sha,
590 unsigned mode,
591 const char *path)
592 {
593 update_file_flags(sha, mode, path, index_only || clean, !index_only);
594 }
595
596 /* Low level file merging, update and removal */
597
598 struct merge_file_info
599 {
600 unsigned char sha[20];
601 unsigned mode;
602 unsigned clean:1,
603 merge:1;
604 };
605
606 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
607 {
608 unsigned long size;
609 enum object_type type;
610
611 if (!hashcmp(sha1, null_sha1)) {
612 mm->ptr = xstrdup("");
613 mm->size = 0;
614 return;
615 }
616
617 mm->ptr = read_sha1_file(sha1, &type, &size);
618 if (!mm->ptr || type != OBJ_BLOB)
619 die("unable to read blob object %s", sha1_to_hex(sha1));
620 mm->size = size;
621 }
622
623 /*
624 * Customizable low-level merge drivers support.
625 */
626
627 struct ll_merge_driver;
628 typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
629 const char *path,
630 mmfile_t *orig,
631 mmfile_t *src1, const char *name1,
632 mmfile_t *src2, const char *name2,
633 mmbuffer_t *result);
634
635 struct ll_merge_driver {
636 const char *name;
637 const char *description;
638 ll_merge_fn fn;
639 const char *recursive;
640 struct ll_merge_driver *next;
641 char *cmdline;
642 };
643
644 /*
645 * Built-in low-levels
646 */
647 static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
648 const char *path_unused,
649 mmfile_t *orig,
650 mmfile_t *src1, const char *name1,
651 mmfile_t *src2, const char *name2,
652 mmbuffer_t *result)
653 {
654 /*
655 * The tentative merge result is "ours" for the final round,
656 * or common ancestor for an internal merge. Still return
657 * "conflicted merge" status.
658 */
659 mmfile_t *stolen = index_only ? orig : src1;
660
661 result->ptr = stolen->ptr;
662 result->size = stolen->size;
663 stolen->ptr = NULL;
664 return 1;
665 }
666
667 static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
668 const char *path_unused,
669 mmfile_t *orig,
670 mmfile_t *src1, const char *name1,
671 mmfile_t *src2, const char *name2,
672 mmbuffer_t *result)
673 {
674 xpparam_t xpp;
675
676 if (buffer_is_binary(orig->ptr, orig->size) ||
677 buffer_is_binary(src1->ptr, src1->size) ||
678 buffer_is_binary(src2->ptr, src2->size)) {
679 warning("Cannot merge binary files: %s vs. %s\n",
680 name1, name2);
681 return ll_binary_merge(drv_unused, path_unused,
682 orig, src1, name1,
683 src2, name2,
684 result);
685 }
686
687 memset(&xpp, 0, sizeof(xpp));
688 return xdl_merge(orig,
689 src1, name1,
690 src2, name2,
691 &xpp, XDL_MERGE_ZEALOUS,
692 result);
693 }
694
695 static int ll_union_merge(const struct ll_merge_driver *drv_unused,
696 const char *path_unused,
697 mmfile_t *orig,
698 mmfile_t *src1, const char *name1,
699 mmfile_t *src2, const char *name2,
700 mmbuffer_t *result)
701 {
702 char *src, *dst;
703 long size;
704 const int marker_size = 7;
705
706 int status = ll_xdl_merge(drv_unused, path_unused,
707 orig, src1, NULL, src2, NULL, result);
708 if (status <= 0)
709 return status;
710 size = result->size;
711 src = dst = result->ptr;
712 while (size) {
713 char ch;
714 if ((marker_size < size) &&
715 (*src == '<' || *src == '=' || *src == '>')) {
716 int i;
717 ch = *src;
718 for (i = 0; i < marker_size; i++)
719 if (src[i] != ch)
720 goto not_a_marker;
721 if (src[marker_size] != '\n')
722 goto not_a_marker;
723 src += marker_size + 1;
724 size -= marker_size + 1;
725 continue;
726 }
727 not_a_marker:
728 do {
729 ch = *src++;
730 *dst++ = ch;
731 size--;
732 } while (ch != '\n' && size);
733 }
734 result->size = dst - result->ptr;
735 return 0;
736 }
737
738 #define LL_BINARY_MERGE 0
739 #define LL_TEXT_MERGE 1
740 #define LL_UNION_MERGE 2
741 static struct ll_merge_driver ll_merge_drv[] = {
742 { "binary", "built-in binary merge", ll_binary_merge },
743 { "text", "built-in 3-way text merge", ll_xdl_merge },
744 { "union", "built-in union merge", ll_union_merge },
745 };
746
747 static void create_temp(mmfile_t *src, char *path)
748 {
749 int fd;
750
751 strcpy(path, ".merge_file_XXXXXX");
752 fd = xmkstemp(path);
753 if (write_in_full(fd, src->ptr, src->size) != src->size)
754 die("unable to write temp-file");
755 close(fd);
756 }
757
758 /*
759 * User defined low-level merge driver support.
760 */
761 static int ll_ext_merge(const struct ll_merge_driver *fn,
762 const char *path,
763 mmfile_t *orig,
764 mmfile_t *src1, const char *name1,
765 mmfile_t *src2, const char *name2,
766 mmbuffer_t *result)
767 {
768 char temp[3][50];
769 char cmdbuf[2048];
770 struct interp table[] = {
771 { "%O" },
772 { "%A" },
773 { "%B" },
774 };
775 struct child_process child;
776 const char *args[20];
777 int status, fd, i;
778 struct stat st;
779
780 if (fn->cmdline == NULL)
781 die("custom merge driver %s lacks command line.", fn->name);
782
783 result->ptr = NULL;
784 result->size = 0;
785 create_temp(orig, temp[0]);
786 create_temp(src1, temp[1]);
787 create_temp(src2, temp[2]);
788
789 interp_set_entry(table, 0, temp[0]);
790 interp_set_entry(table, 1, temp[1]);
791 interp_set_entry(table, 2, temp[2]);
792
793 output(1, "merging %s using %s", path,
794 fn->description ? fn->description : fn->name);
795
796 interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
797
798 memset(&child, 0, sizeof(child));
799 child.argv = args;
800 args[0] = "sh";
801 args[1] = "-c";
802 args[2] = cmdbuf;
803 args[3] = NULL;
804
805 status = run_command(&child);
806 if (status < -ERR_RUN_COMMAND_FORK)
807 ; /* failure in run-command */
808 else
809 status = -status;
810 fd = open(temp[1], O_RDONLY);
811 if (fd < 0)
812 goto bad;
813 if (fstat(fd, &st))
814 goto close_bad;
815 result->size = st.st_size;
816 result->ptr = xmalloc(result->size + 1);
817 if (read_in_full(fd, result->ptr, result->size) != result->size) {
818 free(result->ptr);
819 result->ptr = NULL;
820 result->size = 0;
821 }
822 close_bad:
823 close(fd);
824 bad:
825 for (i = 0; i < 3; i++)
826 unlink(temp[i]);
827 return status;
828 }
829
830 /*
831 * merge.default and merge.driver configuration items
832 */
833 static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
834 static const char *default_ll_merge;
835
836 static int read_merge_config(const char *var, const char *value)
837 {
838 struct ll_merge_driver *fn;
839 const char *ep, *name;
840 int namelen;
841
842 if (!strcmp(var, "merge.default")) {
843 if (value)
844 default_ll_merge = strdup(value);
845 return 0;
846 }
847
848 /*
849 * We are not interested in anything but "merge.<name>.variable";
850 * especially, we do not want to look at variables such as
851 * "merge.summary", "merge.tool", and "merge.verbosity".
852 */
853 if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
854 return 0;
855
856 /*
857 * Find existing one as we might be processing merge.<name>.var2
858 * after seeing merge.<name>.var1.
859 */
860 name = var + 6;
861 namelen = ep - name;
862 for (fn = ll_user_merge; fn; fn = fn->next)
863 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
864 break;
865 if (!fn) {
866 fn = xcalloc(1, sizeof(struct ll_merge_driver));
867 fn->name = xmemdupz(name, namelen);
868 fn->fn = ll_ext_merge;
869 *ll_user_merge_tail = fn;
870 ll_user_merge_tail = &(fn->next);
871 }
872
873 ep++;
874
875 if (!strcmp("name", ep)) {
876 if (!value)
877 return error("%s: lacks value", var);
878 fn->description = strdup(value);
879 return 0;
880 }
881
882 if (!strcmp("driver", ep)) {
883 if (!value)
884 return error("%s: lacks value", var);
885 /*
886 * merge.<name>.driver specifies the command line:
887 *
888 * command-line
889 *
890 * The command-line will be interpolated with the following
891 * tokens and is given to the shell:
892 *
893 * %O - temporary file name for the merge base.
894 * %A - temporary file name for our version.
895 * %B - temporary file name for the other branches' version.
896 *
897 * The external merge driver should write the results in the
898 * file named by %A, and signal that it has done with zero exit
899 * status.
900 */
901 fn->cmdline = strdup(value);
902 return 0;
903 }
904
905 if (!strcmp("recursive", ep)) {
906 if (!value)
907 return error("%s: lacks value", var);
908 fn->recursive = strdup(value);
909 return 0;
910 }
911
912 return 0;
913 }
914
915 static void initialize_ll_merge(void)
916 {
917 if (ll_user_merge_tail)
918 return;
919 ll_user_merge_tail = &ll_user_merge;
920 git_config(read_merge_config);
921 }
922
923 static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
924 {
925 struct ll_merge_driver *fn;
926 const char *name;
927 int i;
928
929 initialize_ll_merge();
930
931 if (ATTR_TRUE(merge_attr))
932 return &ll_merge_drv[LL_TEXT_MERGE];
933 else if (ATTR_FALSE(merge_attr))
934 return &ll_merge_drv[LL_BINARY_MERGE];
935 else if (ATTR_UNSET(merge_attr)) {
936 if (!default_ll_merge)
937 return &ll_merge_drv[LL_TEXT_MERGE];
938 else
939 name = default_ll_merge;
940 }
941 else
942 name = merge_attr;
943
944 for (fn = ll_user_merge; fn; fn = fn->next)
945 if (!strcmp(fn->name, name))
946 return fn;
947
948 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
949 if (!strcmp(ll_merge_drv[i].name, name))
950 return &ll_merge_drv[i];
951
952 /* default to the 3-way */
953 return &ll_merge_drv[LL_TEXT_MERGE];
954 }
955
956 static const char *git_path_check_merge(const char *path)
957 {
958 static struct git_attr_check attr_merge_check;
959
960 if (!attr_merge_check.attr)
961 attr_merge_check.attr = git_attr("merge", 5);
962
963 if (git_checkattr(path, 1, &attr_merge_check))
964 return NULL;
965 return attr_merge_check.value;
966 }
967
968 static int ll_merge(mmbuffer_t *result_buf,
969 struct diff_filespec *o,
970 struct diff_filespec *a,
971 struct diff_filespec *b,
972 const char *branch1,
973 const char *branch2)
974 {
975 mmfile_t orig, src1, src2;
976 char *name1, *name2;
977 int merge_status;
978 const char *ll_driver_name;
979 const struct ll_merge_driver *driver;
980
981 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
982 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
983
984 fill_mm(o->sha1, &orig);
985 fill_mm(a->sha1, &src1);
986 fill_mm(b->sha1, &src2);
987
988 ll_driver_name = git_path_check_merge(a->path);
989 driver = find_ll_merge_driver(ll_driver_name);
990
991 if (index_only && driver->recursive)
992 driver = find_ll_merge_driver(driver->recursive);
993 merge_status = driver->fn(driver, a->path,
994 &orig, &src1, name1, &src2, name2,
995 result_buf);
996
997 free(name1);
998 free(name2);
999 free(orig.ptr);
1000 free(src1.ptr);
1001 free(src2.ptr);
1002 return merge_status;
1003 }
1004
1005 static struct merge_file_info merge_file(struct diff_filespec *o,
1006 struct diff_filespec *a, struct diff_filespec *b,
1007 const char *branch1, const char *branch2)
1008 {
1009 struct merge_file_info result;
1010 result.merge = 0;
1011 result.clean = 1;
1012
1013 if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
1014 result.clean = 0;
1015 if (S_ISREG(a->mode)) {
1016 result.mode = a->mode;
1017 hashcpy(result.sha, a->sha1);
1018 } else {
1019 result.mode = b->mode;
1020 hashcpy(result.sha, b->sha1);
1021 }
1022 } else {
1023 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
1024 result.merge = 1;
1025
1026 result.mode = a->mode == o->mode ? b->mode: a->mode;
1027
1028 if (sha_eq(a->sha1, o->sha1))
1029 hashcpy(result.sha, b->sha1);
1030 else if (sha_eq(b->sha1, o->sha1))
1031 hashcpy(result.sha, a->sha1);
1032 else if (S_ISREG(a->mode)) {
1033 mmbuffer_t result_buf;
1034 int merge_status;
1035
1036 merge_status = ll_merge(&result_buf, o, a, b,
1037 branch1, branch2);
1038
1039 if ((merge_status < 0) || !result_buf.ptr)
1040 die("Failed to execute internal merge");
1041
1042 if (write_sha1_file(result_buf.ptr, result_buf.size,
1043 blob_type, result.sha))
1044 die("Unable to add %s to database",
1045 a->path);
1046
1047 free(result_buf.ptr);
1048 result.clean = (merge_status == 0);
1049 } else {
1050 if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
1051 die("cannot merge modes?");
1052
1053 hashcpy(result.sha, a->sha1);
1054
1055 if (!sha_eq(a->sha1, b->sha1))
1056 result.clean = 0;
1057 }
1058 }
1059
1060 return result;
1061 }
1062
1063 static void conflict_rename_rename(struct rename *ren1,
1064 const char *branch1,
1065 struct rename *ren2,
1066 const char *branch2)
1067 {
1068 char *del[2];
1069 int delp = 0;
1070 const char *ren1_dst = ren1->pair->two->path;
1071 const char *ren2_dst = ren2->pair->two->path;
1072 const char *dst_name1 = ren1_dst;
1073 const char *dst_name2 = ren2_dst;
1074 if (path_list_has_path(&current_directory_set, ren1_dst)) {
1075 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
1076 output(1, "%s is a directory in %s added as %s instead",
1077 ren1_dst, branch2, dst_name1);
1078 remove_file(0, ren1_dst, 0);
1079 }
1080 if (path_list_has_path(&current_directory_set, ren2_dst)) {
1081 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
1082 output(1, "%s is a directory in %s added as %s instead",
1083 ren2_dst, branch1, dst_name2);
1084 remove_file(0, ren2_dst, 0);
1085 }
1086 if (index_only) {
1087 remove_file_from_cache(dst_name1);
1088 remove_file_from_cache(dst_name2);
1089 /*
1090 * Uncomment to leave the conflicting names in the resulting tree
1091 *
1092 * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
1093 * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
1094 */
1095 } else {
1096 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
1097 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
1098 }
1099 while (delp--)
1100 free(del[delp]);
1101 }
1102
1103 static void conflict_rename_dir(struct rename *ren1,
1104 const char *branch1)
1105 {
1106 char *new_path = unique_path(ren1->pair->two->path, branch1);
1107 output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
1108 remove_file(0, ren1->pair->two->path, 0);
1109 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
1110 free(new_path);
1111 }
1112
1113 static void conflict_rename_rename_2(struct rename *ren1,
1114 const char *branch1,
1115 struct rename *ren2,
1116 const char *branch2)
1117 {
1118 char *new_path1 = unique_path(ren1->pair->two->path, branch1);
1119 char *new_path2 = unique_path(ren2->pair->two->path, branch2);
1120 output(1, "Renamed %s to %s and %s to %s instead",
1121 ren1->pair->one->path, new_path1,
1122 ren2->pair->one->path, new_path2);
1123 remove_file(0, ren1->pair->two->path, 0);
1124 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
1125 update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
1126 free(new_path2);
1127 free(new_path1);
1128 }
1129
1130 static int process_renames(struct path_list *a_renames,
1131 struct path_list *b_renames,
1132 const char *a_branch,
1133 const char *b_branch)
1134 {
1135 int clean_merge = 1, i, j;
1136 struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
1137 const struct rename *sre;
1138
1139 for (i = 0; i < a_renames->nr; i++) {
1140 sre = a_renames->items[i].util;
1141 path_list_insert(sre->pair->two->path, &a_by_dst)->util
1142 = sre->dst_entry;
1143 }
1144 for (i = 0; i < b_renames->nr; i++) {
1145 sre = b_renames->items[i].util;
1146 path_list_insert(sre->pair->two->path, &b_by_dst)->util
1147 = sre->dst_entry;
1148 }
1149
1150 for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1151 int compare;
1152 char *src;
1153 struct path_list *renames1, *renames2, *renames2Dst;
1154 struct rename *ren1 = NULL, *ren2 = NULL;
1155 const char *branch1, *branch2;
1156 const char *ren1_src, *ren1_dst;
1157
1158 if (i >= a_renames->nr) {
1159 compare = 1;
1160 ren2 = b_renames->items[j++].util;
1161 } else if (j >= b_renames->nr) {
1162 compare = -1;
1163 ren1 = a_renames->items[i++].util;
1164 } else {
1165 compare = strcmp(a_renames->items[i].path,
1166 b_renames->items[j].path);
1167 if (compare <= 0)
1168 ren1 = a_renames->items[i++].util;
1169 if (compare >= 0)
1170 ren2 = b_renames->items[j++].util;
1171 }
1172
1173 /* TODO: refactor, so that 1/2 are not needed */
1174 if (ren1) {
1175 renames1 = a_renames;
1176 renames2 = b_renames;
1177 renames2Dst = &b_by_dst;
1178 branch1 = a_branch;
1179 branch2 = b_branch;
1180 } else {
1181 struct rename *tmp;
1182 renames1 = b_renames;
1183 renames2 = a_renames;
1184 renames2Dst = &a_by_dst;
1185 branch1 = b_branch;
1186 branch2 = a_branch;
1187 tmp = ren2;
1188 ren2 = ren1;
1189 ren1 = tmp;
1190 }
1191 src = ren1->pair->one->path;
1192
1193 ren1->dst_entry->processed = 1;
1194 ren1->src_entry->processed = 1;
1195
1196 if (ren1->processed)
1197 continue;
1198 ren1->processed = 1;
1199
1200 ren1_src = ren1->pair->one->path;
1201 ren1_dst = ren1->pair->two->path;
1202
1203 if (ren2) {
1204 const char *ren2_src = ren2->pair->one->path;
1205 const char *ren2_dst = ren2->pair->two->path;
1206 /* Renamed in 1 and renamed in 2 */
1207 if (strcmp(ren1_src, ren2_src) != 0)
1208 die("ren1.src != ren2.src");
1209 ren2->dst_entry->processed = 1;
1210 ren2->processed = 1;
1211 if (strcmp(ren1_dst, ren2_dst) != 0) {
1212 clean_merge = 0;
1213 output(1, "CONFLICT (rename/rename): "
1214 "Rename \"%s\"->\"%s\" in branch \"%s\" "
1215 "rename \"%s\"->\"%s\" in \"%s\"%s",
1216 src, ren1_dst, branch1,
1217 src, ren2_dst, branch2,
1218 index_only ? " (left unresolved)": "");
1219 if (index_only) {
1220 remove_file_from_cache(src);
1221 update_file(0, ren1->pair->one->sha1,
1222 ren1->pair->one->mode, src);
1223 }
1224 conflict_rename_rename(ren1, branch1, ren2, branch2);
1225 } else {
1226 struct merge_file_info mfi;
1227 remove_file(1, ren1_src, 1);
1228 mfi = merge_file(ren1->pair->one,
1229 ren1->pair->two,
1230 ren2->pair->two,
1231 branch1,
1232 branch2);
1233 if (mfi.merge || !mfi.clean)
1234 output(1, "Renamed %s->%s", src, ren1_dst);
1235
1236 if (mfi.merge)
1237 output(2, "Auto-merged %s", ren1_dst);
1238
1239 if (!mfi.clean) {
1240 output(1, "CONFLICT (content): merge conflict in %s",
1241 ren1_dst);
1242 clean_merge = 0;
1243
1244 if (!index_only)
1245 update_stages(ren1_dst,
1246 ren1->pair->one,
1247 ren1->pair->two,
1248 ren2->pair->two,
1249 1 /* clear */);
1250 }
1251 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1252 }
1253 } else {
1254 /* Renamed in 1, maybe changed in 2 */
1255 struct path_list_item *item;
1256 /* we only use sha1 and mode of these */
1257 struct diff_filespec src_other, dst_other;
1258 int try_merge, stage = a_renames == renames1 ? 3: 2;
1259
1260 remove_file(1, ren1_src, index_only || stage == 3);
1261
1262 hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
1263 src_other.mode = ren1->src_entry->stages[stage].mode;
1264 hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
1265 dst_other.mode = ren1->dst_entry->stages[stage].mode;
1266
1267 try_merge = 0;
1268
1269 if (path_list_has_path(&current_directory_set, ren1_dst)) {
1270 clean_merge = 0;
1271 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
1272 " directory %s added in %s",
1273 ren1_src, ren1_dst, branch1,
1274 ren1_dst, branch2);
1275 conflict_rename_dir(ren1, branch1);
1276 } else if (sha_eq(src_other.sha1, null_sha1)) {
1277 clean_merge = 0;
1278 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
1279 "and deleted in %s",
1280 ren1_src, ren1_dst, branch1,
1281 branch2);
1282 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1283 } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1284 const char *new_path;
1285 clean_merge = 0;
1286 try_merge = 1;
1287 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
1288 "%s added in %s",
1289 ren1_src, ren1_dst, branch1,
1290 ren1_dst, branch2);
1291 new_path = unique_path(ren1_dst, branch2);
1292 output(1, "Added as %s instead", new_path);
1293 update_file(0, dst_other.sha1, dst_other.mode, new_path);
1294 } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
1295 ren2 = item->util;
1296 clean_merge = 0;
1297 ren2->processed = 1;
1298 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
1299 "Renamed %s->%s in %s",
1300 ren1_src, ren1_dst, branch1,
1301 ren2->pair->one->path, ren2->pair->two->path, branch2);
1302 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
1303 } else
1304 try_merge = 1;
1305
1306 if (try_merge) {
1307 struct diff_filespec *o, *a, *b;
1308 struct merge_file_info mfi;
1309 src_other.path = (char *)ren1_src;
1310
1311 o = ren1->pair->one;
1312 if (a_renames == renames1) {
1313 a = ren1->pair->two;
1314 b = &src_other;
1315 } else {
1316 b = ren1->pair->two;
1317 a = &src_other;
1318 }
1319 mfi = merge_file(o, a, b,
1320 a_branch, b_branch);
1321
1322 if (mfi.clean &&
1323 sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1324 mfi.mode == ren1->pair->two->mode)
1325 /*
1326 * This messaged is part of
1327 * t6022 test. If you change
1328 * it update the test too.
1329 */
1330 output(3, "Skipped %s (merged same as existing)", ren1_dst);
1331 else {
1332 if (mfi.merge || !mfi.clean)
1333 output(1, "Renamed %s => %s", ren1_src, ren1_dst);
1334 if (mfi.merge)
1335 output(2, "Auto-merged %s", ren1_dst);
1336 if (!mfi.clean) {
1337 output(1, "CONFLICT (rename/modify): Merge conflict in %s",
1338 ren1_dst);
1339 clean_merge = 0;
1340
1341 if (!index_only)
1342 update_stages(ren1_dst,
1343 o, a, b, 1);
1344 }
1345 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1346 }
1347 }
1348 }
1349 }
1350 path_list_clear(&a_by_dst, 0);
1351 path_list_clear(&b_by_dst, 0);
1352
1353 return clean_merge;
1354 }
1355
1356 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1357 {
1358 return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1359 }
1360
1361 /* Per entry merge function */
1362 static int process_entry(const char *path, struct stage_data *entry,
1363 const char *branch1,
1364 const char *branch2)
1365 {
1366 /*
1367 printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1368 print_index_entry("\tpath: ", entry);
1369 */
1370 int clean_merge = 1;
1371 unsigned o_mode = entry->stages[1].mode;
1372 unsigned a_mode = entry->stages[2].mode;
1373 unsigned b_mode = entry->stages[3].mode;
1374 unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1375 unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1376 unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1377
1378 if (o_sha && (!a_sha || !b_sha)) {
1379 /* Case A: Deleted in one */
1380 if ((!a_sha && !b_sha) ||
1381 (sha_eq(a_sha, o_sha) && !b_sha) ||
1382 (!a_sha && sha_eq(b_sha, o_sha))) {
1383 /* Deleted in both or deleted in one and
1384 * unchanged in the other */
1385 if (a_sha)
1386 output(2, "Removed %s", path);
1387 /* do not touch working file if it did not exist */
1388 remove_file(1, path, !a_sha);
1389 } else {
1390 /* Deleted in one and changed in the other */
1391 clean_merge = 0;
1392 if (!a_sha) {
1393 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1394 "and modified in %s. Version %s of %s left in tree.",
1395 path, branch1,
1396 branch2, branch2, path);
1397 update_file(0, b_sha, b_mode, path);
1398 } else {
1399 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1400 "and modified in %s. Version %s of %s left in tree.",
1401 path, branch2,
1402 branch1, branch1, path);
1403 update_file(0, a_sha, a_mode, path);
1404 }
1405 }
1406
1407 } else if ((!o_sha && a_sha && !b_sha) ||
1408 (!o_sha && !a_sha && b_sha)) {
1409 /* Case B: Added in one. */
1410 const char *add_branch;
1411 const char *other_branch;
1412 unsigned mode;
1413 const unsigned char *sha;
1414 const char *conf;
1415
1416 if (a_sha) {
1417 add_branch = branch1;
1418 other_branch = branch2;
1419 mode = a_mode;
1420 sha = a_sha;
1421 conf = "file/directory";
1422 } else {
1423 add_branch = branch2;
1424 other_branch = branch1;
1425 mode = b_mode;
1426 sha = b_sha;
1427 conf = "directory/file";
1428 }
1429 if (path_list_has_path(&current_directory_set, path)) {
1430 const char *new_path = unique_path(path, add_branch);
1431 clean_merge = 0;
1432 output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1433 "Added %s as %s",
1434 conf, path, other_branch, path, new_path);
1435 remove_file(0, path, 0);
1436 update_file(0, sha, mode, new_path);
1437 } else {
1438 output(2, "Added %s", path);
1439 update_file(1, sha, mode, path);
1440 }
1441 } else if (a_sha && b_sha) {
1442 /* Case C: Added in both (check for same permissions) and */
1443 /* case D: Modified in both, but differently. */
1444 const char *reason = "content";
1445 struct merge_file_info mfi;
1446 struct diff_filespec o, a, b;
1447
1448 if (!o_sha) {
1449 reason = "add/add";
1450 o_sha = (unsigned char *)null_sha1;
1451 }
1452 output(2, "Auto-merged %s", path);
1453 o.path = a.path = b.path = (char *)path;
1454 hashcpy(o.sha1, o_sha);
1455 o.mode = o_mode;
1456 hashcpy(a.sha1, a_sha);
1457 a.mode = a_mode;
1458 hashcpy(b.sha1, b_sha);
1459 b.mode = b_mode;
1460
1461 mfi = merge_file(&o, &a, &b,
1462 branch1, branch2);
1463
1464 if (mfi.clean)
1465 update_file(1, mfi.sha, mfi.mode, path);
1466 else {
1467 clean_merge = 0;
1468 output(1, "CONFLICT (%s): Merge conflict in %s",
1469 reason, path);
1470
1471 if (index_only)
1472 update_file(0, mfi.sha, mfi.mode, path);
1473 else
1474 update_file_flags(mfi.sha, mfi.mode, path,
1475 0 /* update_cache */, 1 /* update_working_directory */);
1476 }
1477 } else if (!o_sha && !a_sha && !b_sha) {
1478 /*
1479 * this entry was deleted altogether. a_mode == 0 means
1480 * we had that path and want to actively remove it.
1481 */
1482 remove_file(1, path, !a_mode);
1483 } else
1484 die("Fatal merge failure, shouldn't happen.");
1485
1486 return clean_merge;
1487 }
1488
1489 static int merge_trees(struct tree *head,
1490 struct tree *merge,
1491 struct tree *common,
1492 const char *branch1,
1493 const char *branch2,
1494 struct tree **result)
1495 {
1496 int code, clean;
1497
1498 if (subtree_merge) {
1499 merge = shift_tree_object(head, merge);
1500 common = shift_tree_object(head, common);
1501 }
1502
1503 if (sha_eq(common->object.sha1, merge->object.sha1)) {
1504 output(0, "Already uptodate!");
1505 *result = head;
1506 return 1;
1507 }
1508
1509 code = git_merge_trees(index_only, common, head, merge);
1510
1511 if (code != 0)
1512 die("merging of trees %s and %s failed",
1513 sha1_to_hex(head->object.sha1),
1514 sha1_to_hex(merge->object.sha1));
1515
1516 if (unmerged_index()) {
1517 struct path_list *entries, *re_head, *re_merge;
1518 int i;
1519 path_list_clear(&current_file_set, 1);
1520 path_list_clear(&current_directory_set, 1);
1521 get_files_dirs(head);
1522 get_files_dirs(merge);
1523
1524 entries = get_unmerged();
1525 re_head = get_renames(head, common, head, merge, entries);
1526 re_merge = get_renames(merge, common, head, merge, entries);
1527 clean = process_renames(re_head, re_merge,
1528 branch1, branch2);
1529 for (i = 0; i < entries->nr; i++) {
1530 const char *path = entries->items[i].path;
1531 struct stage_data *e = entries->items[i].util;
1532 if (!e->processed
1533 && !process_entry(path, e, branch1, branch2))
1534 clean = 0;
1535 }
1536
1537 path_list_clear(re_merge, 0);
1538 path_list_clear(re_head, 0);
1539 path_list_clear(entries, 1);
1540
1541 }
1542 else
1543 clean = 1;
1544
1545 if (index_only)
1546 *result = git_write_tree();
1547
1548 return clean;
1549 }
1550
1551 static struct commit_list *reverse_commit_list(struct commit_list *list)
1552 {
1553 struct commit_list *next = NULL, *current, *backup;
1554 for (current = list; current; current = backup) {
1555 backup = current->next;
1556 current->next = next;
1557 next = current;
1558 }
1559 return next;
1560 }
1561
1562 /*
1563 * Merge the commits h1 and h2, return the resulting virtual
1564 * commit object and a flag indicating the cleanness of the merge.
1565 */
1566 static int merge(struct commit *h1,
1567 struct commit *h2,
1568 const char *branch1,
1569 const char *branch2,
1570 struct commit_list *ca,
1571 struct commit **result)
1572 {
1573 struct commit_list *iter;
1574 struct commit *merged_common_ancestors;
1575 struct tree *mrtree = mrtree;
1576 int clean;
1577
1578 if (show(4)) {
1579 output(4, "Merging:");
1580 output_commit_title(h1);
1581 output_commit_title(h2);
1582 }
1583
1584 if (!ca) {
1585 ca = get_merge_bases(h1, h2, 1);
1586 ca = reverse_commit_list(ca);
1587 }
1588
1589 if (show(5)) {
1590 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1591 for (iter = ca; iter; iter = iter->next)
1592 output_commit_title(iter->item);
1593 }
1594
1595 merged_common_ancestors = pop_commit(&ca);
1596 if (merged_common_ancestors == NULL) {
1597 /* if there is no common ancestor, make an empty tree */
1598 struct tree *tree = xcalloc(1, sizeof(struct tree));
1599
1600 tree->object.parsed = 1;
1601 tree->object.type = OBJ_TREE;
1602 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1603 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1604 }
1605
1606 for (iter = ca; iter; iter = iter->next) {
1607 call_depth++;
1608 /*
1609 * When the merge fails, the result contains files
1610 * with conflict markers. The cleanness flag is
1611 * ignored, it was never actually used, as result of
1612 * merge_trees has always overwritten it: the committed
1613 * "conflicts" were already resolved.
1614 */
1615 discard_cache();
1616 merge(merged_common_ancestors, iter->item,
1617 "Temporary merge branch 1",
1618 "Temporary merge branch 2",
1619 NULL,
1620 &merged_common_ancestors);
1621 call_depth--;
1622
1623 if (!merged_common_ancestors)
1624 die("merge returned no commit");
1625 }
1626
1627 discard_cache();
1628 if (!call_depth) {
1629 read_cache();
1630 index_only = 0;
1631 } else
1632 index_only = 1;
1633
1634 clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1635 branch1, branch2, &mrtree);
1636
1637 if (index_only) {
1638 *result = make_virtual_commit(mrtree, "merged tree");
1639 commit_list_insert(h1, &(*result)->parents);
1640 commit_list_insert(h2, &(*result)->parents->next);
1641 }
1642 flush_output();
1643 return clean;
1644 }
1645
1646 static const char *better_branch_name(const char *branch)
1647 {
1648 static char githead_env[8 + 40 + 1];
1649 char *name;
1650
1651 if (strlen(branch) != 40)
1652 return branch;
1653 sprintf(githead_env, "GITHEAD_%s", branch);
1654 name = getenv(githead_env);
1655 return name ? name : branch;
1656 }
1657
1658 static struct commit *get_ref(const char *ref)
1659 {
1660 unsigned char sha1[20];
1661 struct object *object;
1662
1663 if (get_sha1(ref, sha1))
1664 die("Could not resolve ref '%s'", ref);
1665 object = deref_tag(parse_object(sha1), ref, strlen(ref));
1666 if (object->type == OBJ_TREE)
1667 return make_virtual_commit((struct tree*)object,
1668 better_branch_name(ref));
1669 if (object->type != OBJ_COMMIT)
1670 return NULL;
1671 if (parse_commit((struct commit *)object))
1672 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1673 return (struct commit *)object;
1674 }
1675
1676 static int merge_config(const char *var, const char *value)
1677 {
1678 if (!strcasecmp(var, "merge.verbosity")) {
1679 verbosity = git_config_int(var, value);
1680 return 0;
1681 }
1682 if (!strcasecmp(var, "diff.renamelimit")) {
1683 rename_limit = git_config_int(var, value);
1684 return 0;
1685 }
1686 return git_default_config(var, value);
1687 }
1688
1689 int main(int argc, char *argv[])
1690 {
1691 static const char *bases[20];
1692 static unsigned bases_count = 0;
1693 int i, clean;
1694 const char *branch1, *branch2;
1695 struct commit *result, *h1, *h2;
1696 struct commit_list *ca = NULL;
1697 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1698 int index_fd;
1699
1700 if (argv[0]) {
1701 int namelen = strlen(argv[0]);
1702 if (8 < namelen &&
1703 !strcmp(argv[0] + namelen - 8, "-subtree"))
1704 subtree_merge = 1;
1705 }
1706
1707 git_config(merge_config);
1708 if (getenv("GIT_MERGE_VERBOSITY"))
1709 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1710
1711 if (argc < 4)
1712 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1713
1714 for (i = 1; i < argc; ++i) {
1715 if (!strcmp(argv[i], "--"))
1716 break;
1717 if (bases_count < sizeof(bases)/sizeof(*bases))
1718 bases[bases_count++] = argv[i];
1719 }
1720 if (argc - i != 3) /* "--" "<head>" "<remote>" */
1721 die("Not handling anything other than two heads merge.");
1722 if (verbosity >= 5)
1723 buffer_output = 0;
1724
1725 branch1 = argv[++i];
1726 branch2 = argv[++i];
1727
1728 h1 = get_ref(branch1);
1729 h2 = get_ref(branch2);
1730
1731 branch1 = better_branch_name(branch1);
1732 branch2 = better_branch_name(branch2);
1733
1734 if (show(3))
1735 printf("Merging %s with %s\n", branch1, branch2);
1736
1737 index_fd = hold_locked_index(lock, 1);
1738
1739 for (i = 0; i < bases_count; i++) {
1740 struct commit *ancestor = get_ref(bases[i]);
1741 ca = commit_list_insert(ancestor, &ca);
1742 }
1743 clean = merge(h1, h2, branch1, branch2, ca, &result);
1744
1745 if (active_cache_changed &&
1746 (write_cache(index_fd, active_cache, active_nr) ||
1747 close(index_fd) || commit_locked_index(lock)))
1748 die ("unable to write %s", get_index_file());
1749
1750 return clean ? 0: 1;
1751 }
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