Merge branch 'rs/daemon-plug-child-leak' into maint
[git] / rerere.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "string-list.h"
4 #include "rerere.h"
5 #include "xdiff-interface.h"
6 #include "dir.h"
7 #include "resolve-undo.h"
8 #include "ll-merge.h"
9 #include "attr.h"
10 #include "pathspec.h"
11
12 #define RESOLVED 0
13 #define PUNTED 1
14 #define THREE_STAGED 2
15 void *RERERE_RESOLVED = &RERERE_RESOLVED;
16
17 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
18 static int rerere_enabled = -1;
19
20 /* automatically update cleanly resolved paths to the index */
21 static int rerere_autoupdate;
22
23 const char *rerere_path(const char *hex, const char *file)
24 {
25         return git_path("rr-cache/%s/%s", hex, file);
26 }
27
28 static int has_rerere_resolution(const char *hex)
29 {
30         struct stat st;
31         return !stat(rerere_path(hex, "postimage"), &st);
32 }
33
34 static void read_rr(struct string_list *rr)
35 {
36         unsigned char sha1[20];
37         char buf[PATH_MAX];
38         FILE *in = fopen(git_path_merge_rr(), "r");
39         if (!in)
40                 return;
41         while (fread(buf, 40, 1, in) == 1) {
42                 int i;
43                 char *name;
44                 if (get_sha1_hex(buf, sha1))
45                         die("corrupt MERGE_RR");
46                 buf[40] = '\0';
47                 name = xstrdup(buf);
48                 if (fgetc(in) != '\t')
49                         die("corrupt MERGE_RR");
50                 for (i = 0; i < sizeof(buf); i++) {
51                         int c = fgetc(in);
52                         if (c < 0)
53                                 die("corrupt MERGE_RR");
54                         buf[i] = c;
55                         if (c == 0)
56                                  break;
57                 }
58                 if (i == sizeof(buf))
59                         die("filename too long");
60                 string_list_insert(rr, buf)->util = name;
61         }
62         fclose(in);
63 }
64
65 static struct lock_file write_lock;
66
67 static int write_rr(struct string_list *rr, int out_fd)
68 {
69         int i;
70         for (i = 0; i < rr->nr; i++) {
71                 const char *path;
72                 int length;
73                 if (!rr->items[i].util)
74                         continue;
75                 path = rr->items[i].string;
76                 length = strlen(path) + 1;
77                 if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
78                     write_str_in_full(out_fd, "\t") != 1 ||
79                     write_in_full(out_fd, path, length) != length)
80                         die("unable to write rerere record");
81         }
82         if (commit_lock_file(&write_lock) != 0)
83                 die("unable to write rerere record");
84         return 0;
85 }
86
87 static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
88 {
89         if (!count || *err)
90                 return;
91         if (fwrite(p, count, 1, fp) != 1)
92                 *err = errno;
93 }
94
95 static inline void ferr_puts(const char *s, FILE *fp, int *err)
96 {
97         ferr_write(s, strlen(s), fp, err);
98 }
99
100 struct rerere_io {
101         int (*getline)(struct strbuf *, struct rerere_io *);
102         FILE *output;
103         int wrerror;
104         /* some more stuff */
105 };
106
107 static void rerere_io_putstr(const char *str, struct rerere_io *io)
108 {
109         if (io->output)
110                 ferr_puts(str, io->output, &io->wrerror);
111 }
112
113 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
114 {
115         char buf[64];
116
117         while (size) {
118                 if (size < sizeof(buf) - 2) {
119                         memset(buf, ch, size);
120                         buf[size] = '\n';
121                         buf[size + 1] = '\0';
122                         size = 0;
123                 } else {
124                         int sz = sizeof(buf) - 1;
125                         if (size <= sz)
126                                 sz -= (sz - size) + 1;
127                         memset(buf, ch, sz);
128                         buf[sz] = '\0';
129                         size -= sz;
130                 }
131                 rerere_io_putstr(buf, io);
132         }
133 }
134
135 static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
136 {
137         if (io->output)
138                 ferr_write(mem, sz, io->output, &io->wrerror);
139 }
140
141 struct rerere_io_file {
142         struct rerere_io io;
143         FILE *input;
144 };
145
146 static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
147 {
148         struct rerere_io_file *io = (struct rerere_io_file *)io_;
149         return strbuf_getwholeline(sb, io->input, '\n');
150 }
151
152 static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
153 {
154         while (marker_size--)
155                 if (*buf++ != marker_char)
156                         return 0;
157         if (want_sp && *buf != ' ')
158                 return 0;
159         return isspace(*buf);
160 }
161
162 static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
163 {
164         git_SHA_CTX ctx;
165         int hunk_no = 0;
166         enum {
167                 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
168         } hunk = RR_CONTEXT;
169         struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
170         struct strbuf buf = STRBUF_INIT;
171
172         if (sha1)
173                 git_SHA1_Init(&ctx);
174
175         while (!io->getline(&buf, io)) {
176                 if (is_cmarker(buf.buf, '<', marker_size, 1)) {
177                         if (hunk != RR_CONTEXT)
178                                 goto bad;
179                         hunk = RR_SIDE_1;
180                 } else if (is_cmarker(buf.buf, '|', marker_size, 0)) {
181                         if (hunk != RR_SIDE_1)
182                                 goto bad;
183                         hunk = RR_ORIGINAL;
184                 } else if (is_cmarker(buf.buf, '=', marker_size, 0)) {
185                         if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
186                                 goto bad;
187                         hunk = RR_SIDE_2;
188                 } else if (is_cmarker(buf.buf, '>', marker_size, 1)) {
189                         if (hunk != RR_SIDE_2)
190                                 goto bad;
191                         if (strbuf_cmp(&one, &two) > 0)
192                                 strbuf_swap(&one, &two);
193                         hunk_no++;
194                         hunk = RR_CONTEXT;
195                         rerere_io_putconflict('<', marker_size, io);
196                         rerere_io_putmem(one.buf, one.len, io);
197                         rerere_io_putconflict('=', marker_size, io);
198                         rerere_io_putmem(two.buf, two.len, io);
199                         rerere_io_putconflict('>', marker_size, io);
200                         if (sha1) {
201                                 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
202                                             one.len + 1);
203                                 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
204                                             two.len + 1);
205                         }
206                         strbuf_reset(&one);
207                         strbuf_reset(&two);
208                 } else if (hunk == RR_SIDE_1)
209                         strbuf_addbuf(&one, &buf);
210                 else if (hunk == RR_ORIGINAL)
211                         ; /* discard */
212                 else if (hunk == RR_SIDE_2)
213                         strbuf_addbuf(&two, &buf);
214                 else
215                         rerere_io_putstr(buf.buf, io);
216                 continue;
217         bad:
218                 hunk = 99; /* force error exit */
219                 break;
220         }
221         strbuf_release(&one);
222         strbuf_release(&two);
223         strbuf_release(&buf);
224
225         if (sha1)
226                 git_SHA1_Final(sha1, &ctx);
227         if (hunk != RR_CONTEXT)
228                 return -1;
229         return hunk_no;
230 }
231
232 static int handle_file(const char *path, unsigned char *sha1, const char *output)
233 {
234         int hunk_no = 0;
235         struct rerere_io_file io;
236         int marker_size = ll_merge_marker_size(path);
237
238         memset(&io, 0, sizeof(io));
239         io.io.getline = rerere_file_getline;
240         io.input = fopen(path, "r");
241         io.io.wrerror = 0;
242         if (!io.input)
243                 return error("Could not open %s", path);
244
245         if (output) {
246                 io.io.output = fopen(output, "w");
247                 if (!io.io.output) {
248                         fclose(io.input);
249                         return error("Could not write %s", output);
250                 }
251         }
252
253         hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
254
255         fclose(io.input);
256         if (io.io.wrerror)
257                 error("There were errors while writing %s (%s)",
258                       path, strerror(io.io.wrerror));
259         if (io.io.output && fclose(io.io.output))
260                 io.io.wrerror = error("Failed to flush %s: %s",
261                                       path, strerror(errno));
262
263         if (hunk_no < 0) {
264                 if (output)
265                         unlink_or_warn(output);
266                 return error("Could not parse conflict hunks in %s", path);
267         }
268         if (io.io.wrerror)
269                 return -1;
270         return hunk_no;
271 }
272
273 struct rerere_io_mem {
274         struct rerere_io io;
275         struct strbuf input;
276 };
277
278 static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
279 {
280         struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
281         char *ep;
282         size_t len;
283
284         strbuf_release(sb);
285         if (!io->input.len)
286                 return -1;
287         ep = memchr(io->input.buf, '\n', io->input.len);
288         if (!ep)
289                 ep = io->input.buf + io->input.len;
290         else if (*ep == '\n')
291                 ep++;
292         len = ep - io->input.buf;
293         strbuf_add(sb, io->input.buf, len);
294         strbuf_remove(&io->input, 0, len);
295         return 0;
296 }
297
298 static int handle_cache(const char *path, unsigned char *sha1, const char *output)
299 {
300         mmfile_t mmfile[3] = {{NULL}};
301         mmbuffer_t result = {NULL, 0};
302         const struct cache_entry *ce;
303         int pos, len, i, hunk_no;
304         struct rerere_io_mem io;
305         int marker_size = ll_merge_marker_size(path);
306
307         /*
308          * Reproduce the conflicted merge in-core
309          */
310         len = strlen(path);
311         pos = cache_name_pos(path, len);
312         if (0 <= pos)
313                 return -1;
314         pos = -pos - 1;
315
316         for (i = 0; i < 3; i++) {
317                 enum object_type type;
318                 unsigned long size;
319                 int j;
320
321                 if (active_nr <= pos)
322                         break;
323                 ce = active_cache[pos++];
324                 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
325                         continue;
326                 j = ce_stage(ce) - 1;
327                 mmfile[j].ptr = read_sha1_file(ce->sha1, &type, &size);
328                 mmfile[j].size = size;
329         }
330         for (i = 0; i < 3; i++) {
331                 if (!mmfile[i].ptr && !mmfile[i].size)
332                         mmfile[i].ptr = xstrdup("");
333         }
334         /*
335          * NEEDSWORK: handle conflicts from merges with
336          * merge.renormalize set, too
337          */
338         ll_merge(&result, path, &mmfile[0], NULL,
339                  &mmfile[1], "ours",
340                  &mmfile[2], "theirs", NULL);
341         for (i = 0; i < 3; i++)
342                 free(mmfile[i].ptr);
343
344         memset(&io, 0, sizeof(io));
345         io.io.getline = rerere_mem_getline;
346         if (output)
347                 io.io.output = fopen(output, "w");
348         else
349                 io.io.output = NULL;
350         strbuf_init(&io.input, 0);
351         strbuf_attach(&io.input, result.ptr, result.size, result.size);
352
353         hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
354         strbuf_release(&io.input);
355         if (io.io.output)
356                 fclose(io.io.output);
357         return hunk_no;
358 }
359
360 static int check_one_conflict(int i, int *type)
361 {
362         const struct cache_entry *e = active_cache[i];
363
364         if (!ce_stage(e)) {
365                 *type = RESOLVED;
366                 return i + 1;
367         }
368
369         *type = PUNTED;
370         if (ce_stage(e) == 1) {
371                 if (active_nr <= ++i)
372                         return i + 1;
373         }
374
375         /* Only handle regular files with both stages #2 and #3 */
376         if (i + 1 < active_nr) {
377                 const struct cache_entry *e2 = active_cache[i];
378                 const struct cache_entry *e3 = active_cache[i + 1];
379                 if (ce_stage(e2) == 2 &&
380                     ce_stage(e3) == 3 &&
381                     ce_same_name(e, e3) &&
382                     S_ISREG(e2->ce_mode) &&
383                     S_ISREG(e3->ce_mode))
384                         *type = THREE_STAGED;
385         }
386
387         /* Skip the entries with the same name */
388         while (i < active_nr && ce_same_name(e, active_cache[i]))
389                 i++;
390         return i;
391 }
392
393 static int find_conflict(struct string_list *conflict)
394 {
395         int i;
396         if (read_cache() < 0)
397                 return error("Could not read index");
398
399         for (i = 0; i < active_nr;) {
400                 int conflict_type;
401                 const struct cache_entry *e = active_cache[i];
402                 i = check_one_conflict(i, &conflict_type);
403                 if (conflict_type == THREE_STAGED)
404                         string_list_insert(conflict, (const char *)e->name);
405         }
406         return 0;
407 }
408
409 int rerere_remaining(struct string_list *merge_rr)
410 {
411         int i;
412         if (setup_rerere(merge_rr, RERERE_READONLY))
413                 return 0;
414         if (read_cache() < 0)
415                 return error("Could not read index");
416
417         for (i = 0; i < active_nr;) {
418                 int conflict_type;
419                 const struct cache_entry *e = active_cache[i];
420                 i = check_one_conflict(i, &conflict_type);
421                 if (conflict_type == PUNTED)
422                         string_list_insert(merge_rr, (const char *)e->name);
423                 else if (conflict_type == RESOLVED) {
424                         struct string_list_item *it;
425                         it = string_list_lookup(merge_rr, (const char *)e->name);
426                         if (it != NULL) {
427                                 free(it->util);
428                                 it->util = RERERE_RESOLVED;
429                         }
430                 }
431         }
432         return 0;
433 }
434
435 static int merge(const char *name, const char *path)
436 {
437         int ret;
438         mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
439         mmbuffer_t result = {NULL, 0};
440
441         if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
442                 return 1;
443
444         if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
445                         read_mmfile(&base, rerere_path(name, "preimage")) ||
446                         read_mmfile(&other, rerere_path(name, "postimage"))) {
447                 ret = 1;
448                 goto out;
449         }
450         ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
451         if (!ret) {
452                 FILE *f;
453
454                 if (utime(rerere_path(name, "postimage"), NULL) < 0)
455                         warning("failed utime() on %s: %s",
456                                         rerere_path(name, "postimage"),
457                                         strerror(errno));
458                 f = fopen(path, "w");
459                 if (!f)
460                         return error("Could not open %s: %s", path,
461                                      strerror(errno));
462                 if (fwrite(result.ptr, result.size, 1, f) != 1)
463                         error("Could not write %s: %s", path, strerror(errno));
464                 if (fclose(f))
465                         return error("Writing %s failed: %s", path,
466                                      strerror(errno));
467         }
468
469 out:
470         free(cur.ptr);
471         free(base.ptr);
472         free(other.ptr);
473         free(result.ptr);
474
475         return ret;
476 }
477
478 static struct lock_file index_lock;
479
480 static void update_paths(struct string_list *update)
481 {
482         int i;
483
484         hold_locked_index(&index_lock, 1);
485
486         for (i = 0; i < update->nr; i++) {
487                 struct string_list_item *item = &update->items[i];
488                 if (add_file_to_cache(item->string, 0))
489                         exit(128);
490         }
491
492         if (active_cache_changed) {
493                 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
494                         die("Unable to write new index file");
495         } else
496                 rollback_lock_file(&index_lock);
497 }
498
499 static int do_plain_rerere(struct string_list *rr, int fd)
500 {
501         struct string_list conflict = STRING_LIST_INIT_DUP;
502         struct string_list update = STRING_LIST_INIT_DUP;
503         int i;
504
505         find_conflict(&conflict);
506
507         /*
508          * MERGE_RR records paths with conflicts immediately after merge
509          * failed.  Some of the conflicted paths might have been hand resolved
510          * in the working tree since then, but the initial run would catch all
511          * and register their preimages.
512          */
513
514         for (i = 0; i < conflict.nr; i++) {
515                 const char *path = conflict.items[i].string;
516                 if (!string_list_has_string(rr, path)) {
517                         unsigned char sha1[20];
518                         char *hex;
519                         int ret;
520                         ret = handle_file(path, sha1, NULL);
521                         if (ret < 1)
522                                 continue;
523                         hex = xstrdup(sha1_to_hex(sha1));
524                         string_list_insert(rr, path)->util = hex;
525                         if (mkdir_in_gitdir(git_path("rr-cache/%s", hex)))
526                                 continue;
527                         handle_file(path, NULL, rerere_path(hex, "preimage"));
528                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
529                 }
530         }
531
532         /*
533          * Now some of the paths that had conflicts earlier might have been
534          * hand resolved.  Others may be similar to a conflict already that
535          * was resolved before.
536          */
537
538         for (i = 0; i < rr->nr; i++) {
539                 int ret;
540                 const char *path = rr->items[i].string;
541                 const char *name = (const char *)rr->items[i].util;
542
543                 if (has_rerere_resolution(name)) {
544                         if (!merge(name, path)) {
545                                 const char *msg;
546                                 if (rerere_autoupdate) {
547                                         string_list_insert(&update, path);
548                                         msg = "Staged '%s' using previous resolution.\n";
549                                 } else
550                                         msg = "Resolved '%s' using previous resolution.\n";
551                                 fprintf(stderr, msg, path);
552                                 goto mark_resolved;
553                         }
554                 }
555
556                 /* Let's see if we have resolved it. */
557                 ret = handle_file(path, NULL, NULL);
558                 if (ret)
559                         continue;
560
561                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
562                 copy_file(rerere_path(name, "postimage"), path, 0666);
563         mark_resolved:
564                 rr->items[i].util = NULL;
565         }
566
567         if (update.nr)
568                 update_paths(&update);
569
570         return write_rr(rr, fd);
571 }
572
573 static void git_rerere_config(void)
574 {
575         git_config_get_bool("rerere.enabled", &rerere_enabled);
576         git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
577         git_config(git_default_config, NULL);
578 }
579
580 static GIT_PATH_FUNC(git_path_rr_cache, "rr-cache")
581
582 static int is_rerere_enabled(void)
583 {
584         int rr_cache_exists;
585
586         if (!rerere_enabled)
587                 return 0;
588
589         rr_cache_exists = is_directory(git_path_rr_cache());
590         if (rerere_enabled < 0)
591                 return rr_cache_exists;
592
593         if (!rr_cache_exists && mkdir_in_gitdir(git_path_rr_cache()))
594                 die("Could not create directory %s", git_path_rr_cache());
595         return 1;
596 }
597
598 int setup_rerere(struct string_list *merge_rr, int flags)
599 {
600         int fd;
601
602         git_rerere_config();
603         if (!is_rerere_enabled())
604                 return -1;
605
606         if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
607                 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
608         if (flags & RERERE_READONLY)
609                 fd = 0;
610         else
611                 fd = hold_lock_file_for_update(&write_lock, git_path_merge_rr(),
612                                                LOCK_DIE_ON_ERROR);
613         read_rr(merge_rr);
614         return fd;
615 }
616
617 int rerere(int flags)
618 {
619         struct string_list merge_rr = STRING_LIST_INIT_DUP;
620         int fd;
621
622         fd = setup_rerere(&merge_rr, flags);
623         if (fd < 0)
624                 return 0;
625         return do_plain_rerere(&merge_rr, fd);
626 }
627
628 static int rerere_forget_one_path(const char *path, struct string_list *rr)
629 {
630         const char *filename;
631         char *hex;
632         unsigned char sha1[20];
633         int ret;
634
635         ret = handle_cache(path, sha1, NULL);
636         if (ret < 1)
637                 return error("Could not parse conflict hunks in '%s'", path);
638         hex = xstrdup(sha1_to_hex(sha1));
639         filename = rerere_path(hex, "postimage");
640         if (unlink(filename))
641                 return (errno == ENOENT
642                         ? error("no remembered resolution for %s", path)
643                         : error("cannot unlink %s: %s", filename, strerror(errno)));
644
645         handle_cache(path, sha1, rerere_path(hex, "preimage"));
646         fprintf(stderr, "Updated preimage for '%s'\n", path);
647
648
649         string_list_insert(rr, path)->util = hex;
650         fprintf(stderr, "Forgot resolution for %s\n", path);
651         return 0;
652 }
653
654 int rerere_forget(struct pathspec *pathspec)
655 {
656         int i, fd;
657         struct string_list conflict = STRING_LIST_INIT_DUP;
658         struct string_list merge_rr = STRING_LIST_INIT_DUP;
659
660         if (read_cache() < 0)
661                 return error("Could not read index");
662
663         fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
664         if (fd < 0)
665                 return 0;
666
667         unmerge_cache(pathspec);
668         find_conflict(&conflict);
669         for (i = 0; i < conflict.nr; i++) {
670                 struct string_list_item *it = &conflict.items[i];
671                 if (!match_pathspec(pathspec, it->string,
672                                     strlen(it->string), 0, NULL, 0))
673                         continue;
674                 rerere_forget_one_path(it->string, &merge_rr);
675         }
676         return write_rr(&merge_rr, fd);
677 }
678
679 static time_t rerere_created_at(const char *name)
680 {
681         struct stat st;
682         return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
683 }
684
685 static time_t rerere_last_used_at(const char *name)
686 {
687         struct stat st;
688         return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
689 }
690
691 static void unlink_rr_item(const char *name)
692 {
693         unlink(rerere_path(name, "thisimage"));
694         unlink(rerere_path(name, "preimage"));
695         unlink(rerere_path(name, "postimage"));
696         rmdir(git_path("rr-cache/%s", name));
697 }
698
699 void rerere_gc(struct string_list *rr)
700 {
701         struct string_list to_remove = STRING_LIST_INIT_DUP;
702         DIR *dir;
703         struct dirent *e;
704         int i, cutoff;
705         time_t now = time(NULL), then;
706         int cutoff_noresolve = 15;
707         int cutoff_resolve = 60;
708
709         if (setup_rerere(rr, 0) < 0)
710                 return;
711
712         git_config_get_int("gc.rerereresolved", &cutoff_resolve);
713         git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
714         git_config(git_default_config, NULL);
715         dir = opendir(git_path("rr-cache"));
716         if (!dir)
717                 die_errno("unable to open rr-cache directory");
718         while ((e = readdir(dir))) {
719                 if (is_dot_or_dotdot(e->d_name))
720                         continue;
721
722                 then = rerere_last_used_at(e->d_name);
723                 if (then) {
724                         cutoff = cutoff_resolve;
725                 } else {
726                         then = rerere_created_at(e->d_name);
727                         if (!then)
728                                 continue;
729                         cutoff = cutoff_noresolve;
730                 }
731                 if (then < now - cutoff * 86400)
732                         string_list_append(&to_remove, e->d_name);
733         }
734         closedir(dir);
735         for (i = 0; i < to_remove.nr; i++)
736                 unlink_rr_item(to_remove.items[i].string);
737         string_list_clear(&to_remove, 0);
738         rollback_lock_file(&write_lock);
739 }
740
741 void rerere_clear(struct string_list *merge_rr)
742 {
743         int i;
744
745         if (setup_rerere(merge_rr, 0) < 0)
746                 return;
747
748         for (i = 0; i < merge_rr->nr; i++) {
749                 const char *name = (const char *)merge_rr->items[i].util;
750                 if (!has_rerere_resolution(name))
751                         unlink_rr_item(name);
752         }
753         unlink_or_warn(git_path_merge_rr());
754         rollback_lock_file(&write_lock);
755 }