sha1-file.c: remove implicit dependency on the_index
[git/git.git] / rerere.c
CommitLineData
5b2fd956 1#include "cache.h"
b2141fc1 2#include "config.h"
697cc8ef 3#include "lockfile.h"
c455c87c 4#include "string-list.h"
5b2fd956 5#include "rerere.h"
5b2fd956 6#include "xdiff-interface.h"
dea4562b
JH
7#include "dir.h"
8#include "resolve-undo.h"
9#include "ll-merge.h"
8588567c 10#include "attr.h"
01a10b0a 11#include "pathspec.h"
cbd53a21 12#include "object-store.h"
1869bbe1 13#include "sha1-lookup.h"
5b2fd956 14
ac49f5ca
MZ
15#define RESOLVED 0
16#define PUNTED 1
17#define THREE_STAGED 2
18void *RERERE_RESOLVED = &RERERE_RESOLVED;
19
5b2fd956
SB
20/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
21static int rerere_enabled = -1;
22
23/* automatically update cleanly resolved paths to the index */
24static int rerere_autoupdate;
25
1869bbe1
JH
26static int rerere_dir_nr;
27static int rerere_dir_alloc;
28
2c7929b1
JH
29#define RR_HAS_POSTIMAGE 1
30#define RR_HAS_PREIMAGE 2
1869bbe1
JH
31static struct rerere_dir {
32 unsigned char sha1[20];
a13d1370
JH
33 int status_alloc, status_nr;
34 unsigned char *status;
1869bbe1
JH
35} **rerere_dir;
36
37static void free_rerere_dirs(void)
38{
39 int i;
a13d1370
JH
40 for (i = 0; i < rerere_dir_nr; i++) {
41 free(rerere_dir[i]->status);
1869bbe1 42 free(rerere_dir[i]);
a13d1370 43 }
88ce3ef6 44 FREE_AND_NULL(rerere_dir);
1869bbe1 45 rerere_dir_nr = rerere_dir_alloc = 0;
1869bbe1
JH
46}
47
1d51eced 48static void free_rerere_id(struct string_list_item *item)
5b2fd956 49{
1d51eced 50 free(item->util);
5b2fd956
SB
51}
52
1d51eced
JH
53static const char *rerere_id_hex(const struct rerere_id *id)
54{
1869bbe1 55 return sha1_to_hex(id->collection->sha1);
1d51eced
JH
56}
57
a13d1370
JH
58static void fit_variant(struct rerere_dir *rr_dir, int variant)
59{
60 variant++;
61 ALLOC_GROW(rr_dir->status, variant, rr_dir->status_alloc);
62 if (rr_dir->status_nr < variant) {
63 memset(rr_dir->status + rr_dir->status_nr,
64 '\0', variant - rr_dir->status_nr);
65 rr_dir->status_nr = variant;
66 }
67}
68
69static void assign_variant(struct rerere_id *id)
70{
71 int variant;
72 struct rerere_dir *rr_dir = id->collection;
73
74 variant = id->variant;
75 if (variant < 0) {
629716d2
JH
76 for (variant = 0; variant < rr_dir->status_nr; variant++)
77 if (!rr_dir->status[variant])
78 break;
a13d1370
JH
79 }
80 fit_variant(rr_dir, variant);
81 id->variant = variant;
1d51eced
JH
82}
83
84const char *rerere_path(const struct rerere_id *id, const char *file)
85{
86 if (!file)
87 return git_path("rr-cache/%s", rerere_id_hex(id));
88
a13d1370
JH
89 if (id->variant <= 0)
90 return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
91
92 return git_path("rr-cache/%s/%s.%d",
93 rerere_id_hex(id), file, id->variant);
5b2fd956
SB
94}
95
a13d1370 96static int is_rr_file(const char *name, const char *filename, int *variant)
2c7929b1 97{
a13d1370
JH
98 const char *suffix;
99 char *ep;
100
101 if (!strcmp(name, filename)) {
102 *variant = 0;
103 return 1;
104 }
105 if (!skip_prefix(name, filename, &suffix) || *suffix != '.')
106 return 0;
107
108 errno = 0;
109 *variant = strtol(suffix + 1, &ep, 10);
110 if (errno || *ep)
111 return 0;
112 return 1;
2c7929b1
JH
113}
114
115static void scan_rerere_dir(struct rerere_dir *rr_dir)
116{
117 struct dirent *de;
118 DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1)));
119
120 if (!dir)
121 return;
122 while ((de = readdir(dir)) != NULL) {
a13d1370
JH
123 int variant;
124
125 if (is_rr_file(de->d_name, "postimage", &variant)) {
126 fit_variant(rr_dir, variant);
127 rr_dir->status[variant] |= RR_HAS_POSTIMAGE;
128 } else if (is_rr_file(de->d_name, "preimage", &variant)) {
129 fit_variant(rr_dir, variant);
130 rr_dir->status[variant] |= RR_HAS_PREIMAGE;
131 }
2c7929b1
JH
132 }
133 closedir(dir);
134}
135
1869bbe1
JH
136static const unsigned char *rerere_dir_sha1(size_t i, void *table)
137{
138 struct rerere_dir **rr_dir = table;
139 return rr_dir[i]->sha1;
140}
141
142static struct rerere_dir *find_rerere_dir(const char *hex)
143{
144 unsigned char sha1[20];
145 struct rerere_dir *rr_dir;
146 int pos;
147
148 if (get_sha1_hex(hex, sha1))
149 return NULL; /* BUG */
150 pos = sha1_pos(sha1, rerere_dir, rerere_dir_nr, rerere_dir_sha1);
151 if (pos < 0) {
152 rr_dir = xmalloc(sizeof(*rr_dir));
153 hashcpy(rr_dir->sha1, sha1);
a13d1370
JH
154 rr_dir->status = NULL;
155 rr_dir->status_nr = 0;
156 rr_dir->status_alloc = 0;
1869bbe1
JH
157 pos = -1 - pos;
158
159 /* Make sure the array is big enough ... */
160 ALLOC_GROW(rerere_dir, rerere_dir_nr + 1, rerere_dir_alloc);
161 /* ... and add it in. */
162 rerere_dir_nr++;
f919ffeb
SG
163 MOVE_ARRAY(rerere_dir + pos + 1, rerere_dir + pos,
164 rerere_dir_nr - pos - 1);
1869bbe1 165 rerere_dir[pos] = rr_dir;
2c7929b1 166 scan_rerere_dir(rr_dir);
1869bbe1
JH
167 }
168 return rerere_dir[pos];
5b2fd956
SB
169}
170
1d51eced 171static int has_rerere_resolution(const struct rerere_id *id)
5b2fd956 172{
05dd9f13 173 const int both = RR_HAS_POSTIMAGE|RR_HAS_PREIMAGE;
a13d1370 174 int variant = id->variant;
1d51eced 175
a13d1370
JH
176 if (variant < 0)
177 return 0;
178 return ((id->collection->status[variant] & both) == both);
5b2fd956
SB
179}
180
1d51eced
JH
181static struct rerere_id *new_rerere_id_hex(char *hex)
182{
183 struct rerere_id *id = xmalloc(sizeof(*id));
1869bbe1 184 id->collection = find_rerere_dir(hex);
a13d1370 185 id->variant = -1; /* not known yet */
1d51eced
JH
186 return id;
187}
188
189static struct rerere_id *new_rerere_id(unsigned char *sha1)
190{
191 return new_rerere_id_hex(sha1_to_hex(sha1));
5b2fd956
SB
192}
193
4b68c2a0
JH
194/*
195 * $GIT_DIR/MERGE_RR file is a collection of records, each of which is
196 * "conflict ID", a HT and pathname, terminated with a NUL, and is
197 * used to keep track of the set of paths that "rerere" may need to
198 * work on (i.e. what is left by the previous invocation of "git
199 * rerere" during the current conflict resolution session).
200 */
c455c87c 201static void read_rr(struct string_list *rr)
5b2fd956 202{
f5800f6a 203 struct strbuf buf = STRBUF_INIT;
102de880 204 FILE *in = fopen_or_warn(git_path_merge_rr(the_repository), "r");
f5800f6a 205
5b2fd956
SB
206 if (!in)
207 return;
f5800f6a
JH
208 while (!strbuf_getwholeline(&buf, in, '\0')) {
209 char *path;
210 unsigned char sha1[20];
1d51eced 211 struct rerere_id *id;
a13d1370 212 int variant;
f5800f6a
JH
213
214 /* There has to be the hash, tab, path and then NUL */
215 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
5b2fd956 216 die("corrupt MERGE_RR");
f5800f6a 217
a13d1370
JH
218 if (buf.buf[40] != '.') {
219 variant = 0;
220 path = buf.buf + 40;
221 } else {
222 errno = 0;
223 variant = strtol(buf.buf + 41, &path, 10);
224 if (errno)
225 die("corrupt MERGE_RR");
226 }
227 if (*(path++) != '\t')
5b2fd956 228 die("corrupt MERGE_RR");
f5800f6a 229 buf.buf[40] = '\0';
1d51eced 230 id = new_rerere_id_hex(buf.buf);
a13d1370 231 id->variant = variant;
1d51eced 232 string_list_insert(rr, path)->util = id;
5b2fd956 233 }
f5800f6a 234 strbuf_release(&buf);
5b2fd956
SB
235 fclose(in);
236}
237
238static struct lock_file write_lock;
239
c455c87c 240static int write_rr(struct string_list *rr, int out_fd)
5b2fd956
SB
241{
242 int i;
243 for (i = 0; i < rr->nr; i++) {
e2cb6a95 244 struct strbuf buf = STRBUF_INIT;
1d51eced 245 struct rerere_id *id;
e2cb6a95
JH
246
247 assert(rr->items[i].util != RERERE_RESOLVED);
1d51eced
JH
248
249 id = rr->items[i].util;
250 if (!id)
5b2fd956 251 continue;
a13d1370
JH
252 assert(id->variant >= 0);
253 if (0 < id->variant)
254 strbuf_addf(&buf, "%s.%d\t%s%c",
255 rerere_id_hex(id), id->variant,
256 rr->items[i].string, 0);
257 else
258 strbuf_addf(&buf, "%s\t%s%c",
259 rerere_id_hex(id),
260 rr->items[i].string, 0);
261
06f46f23 262 if (write_in_full(out_fd, buf.buf, buf.len) < 0)
5b2fd956 263 die("unable to write rerere record");
e2cb6a95
JH
264
265 strbuf_release(&buf);
5b2fd956
SB
266 }
267 if (commit_lock_file(&write_lock) != 0)
268 die("unable to write rerere record");
269 return 0;
270}
271
a96847cc
JH
272/*
273 * "rerere" interacts with conflicted file contents using this I/O
274 * abstraction. It reads a conflicted contents from one place via
275 * "getline()" method, and optionally can write it out after
276 * normalizing the conflicted hunks to the "output". Subclasses of
277 * rerere_io embed this structure at the beginning of their own
278 * rerere_io object.
279 */
280struct rerere_io {
281 int (*getline)(struct strbuf *, struct rerere_io *);
282 FILE *output;
283 int wrerror;
284 /* some more stuff */
285};
286
47d32af2
AR
287static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
288{
289 if (!count || *err)
290 return;
291 if (fwrite(p, count, 1, fp) != 1)
292 *err = errno;
293}
294
295static inline void ferr_puts(const char *s, FILE *fp, int *err)
296{
297 ferr_write(s, strlen(s), fp, err);
298}
299
27d6b085
JH
300static void rerere_io_putstr(const char *str, struct rerere_io *io)
301{
302 if (io->output)
303 ferr_puts(str, io->output, &io->wrerror);
304}
305
a96847cc
JH
306/*
307 * Write a conflict marker to io->output (if defined).
308 */
191f2417
JH
309static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
310{
311 char buf[64];
312
313 while (size) {
d3c2749d 314 if (size <= sizeof(buf) - 2) {
191f2417
JH
315 memset(buf, ch, size);
316 buf[size] = '\n';
317 buf[size + 1] = '\0';
318 size = 0;
319 } else {
320 int sz = sizeof(buf) - 1;
d3c2749d
JH
321
322 /*
323 * Make sure we will not write everything out
324 * in this round by leaving at least 1 byte
325 * for the next round, giving the next round
326 * a chance to add the terminating LF. Yuck.
327 */
191f2417
JH
328 if (size <= sz)
329 sz -= (sz - size) + 1;
330 memset(buf, ch, sz);
331 buf[sz] = '\0';
332 size -= sz;
333 }
334 rerere_io_putstr(buf, io);
335 }
336}
337
27d6b085
JH
338static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
339{
340 if (io->output)
341 ferr_write(mem, sz, io->output, &io->wrerror);
342}
343
a96847cc
JH
344/*
345 * Subclass of rerere_io that reads from an on-disk file
346 */
27d6b085
JH
347struct rerere_io_file {
348 struct rerere_io io;
349 FILE *input;
350};
351
a96847cc
JH
352/*
353 * ... and its getline() method implementation
354 */
27d6b085
JH
355static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
356{
357 struct rerere_io_file *io = (struct rerere_io_file *)io_;
358 return strbuf_getwholeline(sb, io->input, '\n');
359}
360
67711cdc
JH
361/*
362 * Require the exact number of conflict marker letters, no more, no
363 * less, followed by SP or any whitespace
364 * (including LF).
365 */
366static int is_cmarker(char *buf, int marker_char, int marker_size)
191f2417 367{
67711cdc
JH
368 int want_sp;
369
370 /*
371 * The beginning of our version and the end of their version
372 * always are labeled like "<<<<< ours" or ">>>>> theirs",
373 * hence we set want_sp for them. Note that the version from
374 * the common ancestor in diff3-style output is not always
375 * labelled (e.g. "||||| common" is often seen but "|||||"
376 * alone is also valid), so we do not set want_sp.
377 */
378 want_sp = (marker_char == '<') || (marker_char == '>');
379
191f2417
JH
380 while (marker_size--)
381 if (*buf++ != marker_char)
382 return 0;
383 if (want_sp && *buf != ' ')
384 return 0;
385 return isspace(*buf);
386}
387
cc899eca
JH
388/*
389 * Read contents a file with conflicts, normalize the conflicts
390 * by (1) discarding the common ancestor version in diff3-style,
391 * (2) reordering our side and their side so that whichever sorts
392 * alphabetically earlier comes before the other one, while
393 * computing the "conflict ID", which is just an SHA-1 hash of
394 * one side of the conflict, NUL, the other side of the conflict,
395 * and NUL concatenated together.
396 *
397 * Return the number of conflict hunks found.
398 *
399 * NEEDSWORK: the logic and theory of operation behind this conflict
400 * normalization may deserve to be documented somewhere, perhaps in
401 * Documentation/technical/rerere.txt.
402 */
191f2417 403static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
5b2fd956 404{
9126f009 405 git_SHA_CTX ctx;
cc58d7df
JH
406 int hunk_no = 0;
407 enum {
4b05548f 408 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
cc58d7df 409 } hunk = RR_CONTEXT;
f285a2d7 410 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
d58ee6db 411 struct strbuf buf = STRBUF_INIT;
5b2fd956
SB
412
413 if (sha1)
9126f009 414 git_SHA1_Init(&ctx);
5b2fd956 415
27d6b085 416 while (!io->getline(&buf, io)) {
67711cdc 417 if (is_cmarker(buf.buf, '<', marker_size)) {
cc58d7df 418 if (hunk != RR_CONTEXT)
5b2fd956 419 goto bad;
cc58d7df 420 hunk = RR_SIDE_1;
67711cdc 421 } else if (is_cmarker(buf.buf, '|', marker_size)) {
cc58d7df 422 if (hunk != RR_SIDE_1)
5b2fd956 423 goto bad;
387c9d49 424 hunk = RR_ORIGINAL;
67711cdc 425 } else if (is_cmarker(buf.buf, '=', marker_size)) {
387c9d49 426 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
5b2fd956 427 goto bad;
cc58d7df 428 hunk = RR_SIDE_2;
67711cdc 429 } else if (is_cmarker(buf.buf, '>', marker_size)) {
cc58d7df 430 if (hunk != RR_SIDE_2)
5b2fd956
SB
431 goto bad;
432 if (strbuf_cmp(&one, &two) > 0)
433 strbuf_swap(&one, &two);
434 hunk_no++;
cc58d7df 435 hunk = RR_CONTEXT;
191f2417 436 rerere_io_putconflict('<', marker_size, io);
27d6b085 437 rerere_io_putmem(one.buf, one.len, io);
191f2417 438 rerere_io_putconflict('=', marker_size, io);
27d6b085 439 rerere_io_putmem(two.buf, two.len, io);
191f2417 440 rerere_io_putconflict('>', marker_size, io);
5b2fd956 441 if (sha1) {
9126f009 442 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
5b2fd956 443 one.len + 1);
9126f009 444 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
5b2fd956
SB
445 two.len + 1);
446 }
447 strbuf_reset(&one);
448 strbuf_reset(&two);
cc58d7df 449 } else if (hunk == RR_SIDE_1)
e992d1eb 450 strbuf_addbuf(&one, &buf);
387c9d49
JH
451 else if (hunk == RR_ORIGINAL)
452 ; /* discard */
cc58d7df 453 else if (hunk == RR_SIDE_2)
e992d1eb 454 strbuf_addbuf(&two, &buf);
27d6b085
JH
455 else
456 rerere_io_putstr(buf.buf, io);
5b2fd956
SB
457 continue;
458 bad:
459 hunk = 99; /* force error exit */
460 break;
461 }
462 strbuf_release(&one);
463 strbuf_release(&two);
d58ee6db 464 strbuf_release(&buf);
5b2fd956 465
5b2fd956 466 if (sha1)
9126f009 467 git_SHA1_Final(sha1, &ctx);
27d6b085
JH
468 if (hunk != RR_CONTEXT)
469 return -1;
470 return hunk_no;
471}
472
cc899eca
JH
473/*
474 * Scan the path for conflicts, do the "handle_path()" thing above, and
475 * return the number of conflict hunks found.
476 */
27d6b085
JH
477static int handle_file(const char *path, unsigned char *sha1, const char *output)
478{
479 int hunk_no = 0;
480 struct rerere_io_file io;
32eaa468 481 int marker_size = ll_merge_marker_size(&the_index, path);
27d6b085
JH
482
483 memset(&io, 0, sizeof(io));
484 io.io.getline = rerere_file_getline;
485 io.input = fopen(path, "r");
486 io.io.wrerror = 0;
487 if (!io.input)
5118d7f4 488 return error_errno("Could not open %s", path);
27d6b085
JH
489
490 if (output) {
491 io.io.output = fopen(output, "w");
492 if (!io.io.output) {
f7566f07 493 error_errno("Could not write %s", output);
27d6b085 494 fclose(io.input);
f7566f07 495 return -1;
27d6b085
JH
496 }
497 }
498
191f2417 499 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
27d6b085
JH
500
501 fclose(io.input);
502 if (io.io.wrerror)
503 error("There were errors while writing %s (%s)",
504 path, strerror(io.io.wrerror));
505 if (io.io.output && fclose(io.io.output))
033e011e 506 io.io.wrerror = error_errno("Failed to flush %s", path);
27d6b085
JH
507
508 if (hunk_no < 0) {
5b2fd956 509 if (output)
691f1a28 510 unlink_or_warn(output);
5b2fd956
SB
511 return error("Could not parse conflict hunks in %s", path);
512 }
27d6b085 513 if (io.io.wrerror)
47d32af2 514 return -1;
5b2fd956
SB
515 return hunk_no;
516}
517
4b68c2a0
JH
518/*
519 * Look at a cache entry at "i" and see if it is not conflicting,
520 * conflicting and we are willing to handle, or conflicting and
521 * we are unable to handle, and return the determination in *type.
522 * Return the cache index to be looked at next, by skipping the
523 * stages we have already looked at in this invocation of this
524 * function.
525 */
ac49f5ca 526static int check_one_conflict(int i, int *type)
5b2fd956 527{
9c5e6c80 528 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
529
530 if (!ce_stage(e)) {
531 *type = RESOLVED;
532 return i + 1;
533 }
534
535 *type = PUNTED;
5eda906b 536 while (ce_stage(active_cache[i]) == 1)
fb70a06d 537 i++;
ac49f5ca
MZ
538
539 /* Only handle regular files with both stages #2 and #3 */
540 if (i + 1 < active_nr) {
9c5e6c80
NTND
541 const struct cache_entry *e2 = active_cache[i];
542 const struct cache_entry *e3 = active_cache[i + 1];
5b2fd956
SB
543 if (ce_stage(e2) == 2 &&
544 ce_stage(e3) == 3 &&
ac49f5ca 545 ce_same_name(e, e3) &&
5b2fd956 546 S_ISREG(e2->ce_mode) &&
ac49f5ca
MZ
547 S_ISREG(e3->ce_mode))
548 *type = THREE_STAGED;
549 }
550
551 /* Skip the entries with the same name */
552 while (i < active_nr && ce_same_name(e, active_cache[i]))
553 i++;
554 return i;
555}
556
4b68c2a0
JH
557/*
558 * Scan the index and find paths that have conflicts that rerere can
559 * handle, i.e. the ones that has both stages #2 and #3.
560 *
561 * NEEDSWORK: we do not record or replay a previous "resolve by
562 * deletion" for a delete-modify conflict, as that is inherently risky
563 * without knowing what modification is being discarded. The only
564 * safe case, i.e. both side doing the deletion and modification that
565 * are identical to the previous round, might want to be handled,
566 * though.
567 */
ac49f5ca
MZ
568static int find_conflict(struct string_list *conflict)
569{
570 int i;
571 if (read_cache() < 0)
572 return error("Could not read index");
573
574 for (i = 0; i < active_nr;) {
575 int conflict_type;
9c5e6c80 576 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
577 i = check_one_conflict(i, &conflict_type);
578 if (conflict_type == THREE_STAGED)
579 string_list_insert(conflict, (const char *)e->name);
580 }
581 return 0;
582}
583
4b68c2a0
JH
584/*
585 * The merge_rr list is meant to hold outstanding conflicted paths
586 * that rerere could handle. Abuse the list by adding other types of
587 * entries to allow the caller to show "rerere remaining".
588 *
589 * - Conflicted paths that rerere does not handle are added
590 * - Conflicted paths that have been resolved are marked as such
591 * by storing RERERE_RESOLVED to .util field (where conflict ID
592 * is expected to be stored).
593 *
594 * Do *not* write MERGE_RR file out after calling this function.
595 *
596 * NEEDSWORK: we may want to fix the caller that implements "rerere
597 * remaining" to do this without abusing merge_rr.
598 */
ac49f5ca
MZ
599int rerere_remaining(struct string_list *merge_rr)
600{
601 int i;
9dd330e6
JK
602 if (setup_rerere(merge_rr, RERERE_READONLY))
603 return 0;
ac49f5ca
MZ
604 if (read_cache() < 0)
605 return error("Could not read index");
606
607 for (i = 0; i < active_nr;) {
608 int conflict_type;
9c5e6c80 609 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
610 i = check_one_conflict(i, &conflict_type);
611 if (conflict_type == PUNTED)
612 string_list_insert(merge_rr, (const char *)e->name);
613 else if (conflict_type == RESOLVED) {
614 struct string_list_item *it;
615 it = string_list_lookup(merge_rr, (const char *)e->name);
616 if (it != NULL) {
1d51eced 617 free_rerere_id(it);
ac49f5ca
MZ
618 it->util = RERERE_RESOLVED;
619 }
5b2fd956
SB
620 }
621 }
622 return 0;
623}
624
0ce02b36
JH
625/*
626 * Try using the given conflict resolution "ID" to see
627 * if that recorded conflict resolves cleanly what we
628 * got in the "cur".
629 */
630static int try_merge(const struct rerere_id *id, const char *path,
631 mmfile_t *cur, mmbuffer_t *result)
632{
633 int ret;
634 mmfile_t base = {NULL, 0}, other = {NULL, 0};
635
636 if (read_mmfile(&base, rerere_path(id, "preimage")) ||
637 read_mmfile(&other, rerere_path(id, "postimage")))
638 ret = 1;
639 else
640 /*
641 * A three-way merge. Note that this honors user-customizable
642 * low-level merge driver settings.
643 */
32eaa468
NTND
644 ret = ll_merge(result, path, &base, NULL, cur, "", &other, "",
645 &the_index, NULL);
0ce02b36
JH
646
647 free(base.ptr);
648 free(other.ptr);
649
650 return ret;
651}
652
cc899eca 653/*
18bb9934 654 * Find the conflict identified by "id"; the change between its
cc899eca
JH
655 * "preimage" (i.e. a previous contents with conflict markers) and its
656 * "postimage" (i.e. the corresponding contents with conflicts
657 * resolved) may apply cleanly to the contents stored in "path", i.e.
658 * the conflict this time around.
659 *
660 * Returns 0 for successful replay of recorded resolution, or non-zero
661 * for failure.
662 */
1d51eced 663static int merge(const struct rerere_id *id, const char *path)
5b2fd956 664{
15ed07d5 665 FILE *f;
5b2fd956 666 int ret;
0ce02b36 667 mmfile_t cur = {NULL, 0};
5b2fd956 668 mmbuffer_t result = {NULL, 0};
5b2fd956 669
cc899eca
JH
670 /*
671 * Normalize the conflicts in path and write it out to
672 * "thisimage" temporary file.
673 */
0ce02b36
JH
674 if ((handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) ||
675 read_mmfile(&cur, rerere_path(id, "thisimage"))) {
689b8c29
BW
676 ret = 1;
677 goto out;
678 }
cc899eca 679
0ce02b36 680 ret = try_merge(id, path, &cur, &result);
15ed07d5
JH
681 if (ret)
682 goto out;
683
684 /*
685 * A successful replay of recorded resolution.
686 * Mark that "postimage" was used to help gc.
687 */
688 if (utime(rerere_path(id, "postimage"), NULL) < 0)
033e011e
NTND
689 warning_errno("failed utime() on %s",
690 rerere_path(id, "postimage"));
15ed07d5
JH
691
692 /* Update "path" with the resolution */
693 f = fopen(path, "w");
694 if (!f)
033e011e 695 return error_errno("Could not open %s", path);
15ed07d5 696 if (fwrite(result.ptr, result.size, 1, f) != 1)
033e011e 697 error_errno("Could not write %s", path);
15ed07d5 698 if (fclose(f))
033e011e 699 return error_errno("Writing %s failed", path);
5b2fd956 700
689b8c29 701out:
5b2fd956 702 free(cur.ptr);
5b2fd956
SB
703 free(result.ptr);
704
705 return ret;
706}
707
89ea9035 708static void update_paths(struct string_list *update)
5b2fd956 709{
0fa5a2ed 710 struct lock_file index_lock = LOCK_INIT;
5b2fd956 711 int i;
5b2fd956 712
b3e83cc7 713 hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
5b2fd956
SB
714
715 for (i = 0; i < update->nr; i++) {
c455c87c 716 struct string_list_item *item = &update->items[i];
89ea9035
JN
717 if (add_file_to_cache(item->string, 0))
718 exit(128);
a14c7ab8
JH
719 fprintf(stderr, "Staged '%s' using previous resolution.\n",
720 item->string);
5b2fd956
SB
721 }
722
61000814
723 if (write_locked_index(&the_index, &index_lock,
724 COMMIT_LOCK | SKIP_IF_UNCHANGED))
725 die("Unable to write new index file");
5b2fd956
SB
726}
727
629716d2
JH
728static void remove_variant(struct rerere_id *id)
729{
730 unlink_or_warn(rerere_path(id, "postimage"));
731 unlink_or_warn(rerere_path(id, "preimage"));
732 id->collection->status[id->variant] = 0;
733}
734
8e7768b2
JH
735/*
736 * The path indicated by rr_item may still have conflict for which we
737 * have a recorded resolution, in which case replay it and optionally
738 * update it. Or it may have been resolved by the user and we may
739 * only have the preimage for that conflict, in which case the result
740 * needs to be recorded as a resolution in a postimage file.
741 */
742static void do_rerere_one_path(struct string_list_item *rr_item,
743 struct string_list *update)
744{
745 const char *path = rr_item->string;
a13d1370 746 struct rerere_id *id = rr_item->util;
629716d2 747 struct rerere_dir *rr_dir = id->collection;
a13d1370
JH
748 int variant;
749
a13d1370 750 variant = id->variant;
8e7768b2 751
629716d2
JH
752 /* Has the user resolved it already? */
753 if (variant >= 0) {
754 if (!handle_file(path, NULL, NULL)) {
755 copy_file(rerere_path(id, "postimage"), path, 0666);
756 id->collection->status[variant] |= RR_HAS_POSTIMAGE;
757 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
758 free_rerere_id(rr_item);
759 rr_item->util = NULL;
760 return;
761 }
c0a5423b 762 /*
629716d2
JH
763 * There may be other variants that can cleanly
764 * replay. Try them and update the variant number for
765 * this one.
c0a5423b 766 */
629716d2
JH
767 }
768
769 /* Does any existing resolution apply cleanly? */
770 for (variant = 0; variant < rr_dir->status_nr; variant++) {
771 const int both = RR_HAS_PREIMAGE | RR_HAS_POSTIMAGE;
772 struct rerere_id vid = *id;
773
774 if ((rr_dir->status[variant] & both) != both)
775 continue;
8e7768b2 776
629716d2
JH
777 vid.variant = variant;
778 if (merge(&vid, path))
779 continue; /* failed to replay */
780
781 /*
782 * If there already is a different variant that applies
783 * cleanly, there is no point maintaining our own variant.
784 */
785 if (0 <= id->variant && id->variant != variant)
786 remove_variant(id);
8e7768b2
JH
787
788 if (rerere_autoupdate)
789 string_list_insert(update, path);
790 else
791 fprintf(stderr,
792 "Resolved '%s' using previous resolution.\n",
793 path);
629716d2
JH
794 free_rerere_id(rr_item);
795 rr_item->util = NULL;
925d73c4 796 return;
8e7768b2 797 }
629716d2
JH
798
799 /* None of the existing one applies; we need a new variant */
800 assign_variant(id);
801
802 variant = id->variant;
803 handle_file(path, NULL, rerere_path(id, "preimage"));
804 if (id->collection->status[variant] & RR_HAS_POSTIMAGE) {
805 const char *path = rerere_path(id, "postimage");
806 if (unlink(path))
807 die_errno("cannot unlink stray '%s'", path);
808 id->collection->status[variant] &= ~RR_HAS_POSTIMAGE;
809 }
810 id->collection->status[variant] |= RR_HAS_PREIMAGE;
811 fprintf(stderr, "Recorded preimage for '%s'\n", path);
8e7768b2
JH
812}
813
c455c87c 814static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956 815{
183113a5
TF
816 struct string_list conflict = STRING_LIST_INIT_DUP;
817 struct string_list update = STRING_LIST_INIT_DUP;
5b2fd956
SB
818 int i;
819
820 find_conflict(&conflict);
821
822 /*
cc899eca
JH
823 * MERGE_RR records paths with conflicts immediately after
824 * merge failed. Some of the conflicted paths might have been
825 * hand resolved in the working tree since then, but the
826 * initial run would catch all and register their preimages.
5b2fd956 827 */
5b2fd956 828 for (i = 0; i < conflict.nr; i++) {
1d51eced 829 struct rerere_id *id;
c7a25d37 830 unsigned char sha1[20];
c455c87c 831 const char *path = conflict.items[i].string;
1d51eced 832 int ret;
5b2fd956 833
c7a25d37
JH
834 if (string_list_has_string(rr, path))
835 continue;
5b2fd956 836
c7a25d37
JH
837 /*
838 * Ask handle_file() to scan and assign a
839 * conflict ID. No need to write anything out
840 * yet.
841 */
842 ret = handle_file(path, sha1, NULL);
843 if (ret < 1)
844 continue;
5b2fd956 845
1d51eced 846 id = new_rerere_id(sha1);
18bb9934 847 string_list_insert(rr, path)->util = id;
cc899eca 848
c0a5423b
JH
849 /* Ensure that the directory exists. */
850 mkdir_in_gitdir(rerere_path(id, NULL));
5b2fd956
SB
851 }
852
8e7768b2
JH
853 for (i = 0; i < rr->nr; i++)
854 do_rerere_one_path(&rr->items[i], &update);
5b2fd956
SB
855
856 if (update.nr)
857 update_paths(&update);
858
859 return write_rr(rr, fd);
860}
861
633e5ad3 862static void git_rerere_config(void)
5b2fd956 863{
633e5ad3
TA
864 git_config_get_bool("rerere.enabled", &rerere_enabled);
865 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
866 git_config(git_default_config, NULL);
5b2fd956
SB
867}
868
f932729c
JK
869static GIT_PATH_FUNC(git_path_rr_cache, "rr-cache")
870
5b2fd956
SB
871static int is_rerere_enabled(void)
872{
5b2fd956
SB
873 int rr_cache_exists;
874
875 if (!rerere_enabled)
876 return 0;
877
f932729c 878 rr_cache_exists = is_directory(git_path_rr_cache());
5b2fd956
SB
879 if (rerere_enabled < 0)
880 return rr_cache_exists;
881
f932729c
JK
882 if (!rr_cache_exists && mkdir_in_gitdir(git_path_rr_cache()))
883 die("Could not create directory %s", git_path_rr_cache());
5b2fd956
SB
884 return 1;
885}
886
cb6020bb 887int setup_rerere(struct string_list *merge_rr, int flags)
5b2fd956
SB
888{
889 int fd;
890
633e5ad3 891 git_rerere_config();
5b2fd956
SB
892 if (!is_rerere_enabled())
893 return -1;
894
cb6020bb
JH
895 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
896 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
9dd330e6
JK
897 if (flags & RERERE_READONLY)
898 fd = 0;
899 else
102de880
SB
900 fd = hold_lock_file_for_update(&write_lock,
901 git_path_merge_rr(the_repository),
9dd330e6 902 LOCK_DIE_ON_ERROR);
5b2fd956
SB
903 read_rr(merge_rr);
904 return fd;
905}
906
cc899eca
JH
907/*
908 * The main entry point that is called internally from codepaths that
909 * perform mergy operations, possibly leaving conflicted index entries
910 * and working tree files.
911 */
cb6020bb 912int rerere(int flags)
5b2fd956 913{
183113a5 914 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1869bbe1 915 int fd, status;
5b2fd956 916
cb6020bb 917 fd = setup_rerere(&merge_rr, flags);
5b2fd956
SB
918 if (fd < 0)
919 return 0;
1869bbe1
JH
920 status = do_plain_rerere(&merge_rr, fd);
921 free_rerere_dirs();
922 return status;
5b2fd956 923}
dea4562b 924
3d730ed9
JH
925/*
926 * Subclass of rerere_io that reads from an in-core buffer that is a
927 * strbuf
928 */
929struct rerere_io_mem {
930 struct rerere_io io;
931 struct strbuf input;
932};
933
934/*
935 * ... and its getline() method implementation
936 */
937static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
938{
939 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
940 char *ep;
941 size_t len;
942
943 strbuf_release(sb);
944 if (!io->input.len)
945 return -1;
946 ep = memchr(io->input.buf, '\n', io->input.len);
947 if (!ep)
948 ep = io->input.buf + io->input.len;
949 else if (*ep == '\n')
950 ep++;
951 len = ep - io->input.buf;
952 strbuf_add(sb, io->input.buf, len);
953 strbuf_remove(&io->input, 0, len);
954 return 0;
955}
956
957static int handle_cache(const char *path, unsigned char *sha1, const char *output)
958{
959 mmfile_t mmfile[3] = {{NULL}};
960 mmbuffer_t result = {NULL, 0};
961 const struct cache_entry *ce;
962 int pos, len, i, hunk_no;
963 struct rerere_io_mem io;
32eaa468 964 int marker_size = ll_merge_marker_size(&the_index, path);
3d730ed9
JH
965
966 /*
967 * Reproduce the conflicted merge in-core
968 */
969 len = strlen(path);
970 pos = cache_name_pos(path, len);
971 if (0 <= pos)
972 return -1;
973 pos = -pos - 1;
974
975 while (pos < active_nr) {
976 enum object_type type;
977 unsigned long size;
978
979 ce = active_cache[pos++];
980 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
981 break;
982 i = ce_stage(ce) - 1;
983 if (!mmfile[i].ptr) {
b4f5aca4 984 mmfile[i].ptr = read_object_file(&ce->oid, &type,
985 &size);
3d730ed9
JH
986 mmfile[i].size = size;
987 }
988 }
989 for (i = 0; i < 3; i++)
990 if (!mmfile[i].ptr && !mmfile[i].size)
991 mmfile[i].ptr = xstrdup("");
992
993 /*
994 * NEEDSWORK: handle conflicts from merges with
995 * merge.renormalize set, too?
996 */
997 ll_merge(&result, path, &mmfile[0], NULL,
998 &mmfile[1], "ours",
32eaa468
NTND
999 &mmfile[2], "theirs",
1000 &the_index, NULL);
3d730ed9
JH
1001 for (i = 0; i < 3; i++)
1002 free(mmfile[i].ptr);
1003
1004 memset(&io, 0, sizeof(io));
1005 io.io.getline = rerere_mem_getline;
1006 if (output)
1007 io.io.output = fopen(output, "w");
1008 else
1009 io.io.output = NULL;
1010 strbuf_init(&io.input, 0);
1011 strbuf_attach(&io.input, result.ptr, result.size, result.size);
1012
1013 /*
1014 * Grab the conflict ID and optionally write the original
1015 * contents with conflict markers out.
1016 */
1017 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
1018 strbuf_release(&io.input);
1019 if (io.io.output)
1020 fclose(io.io.output);
1021 return hunk_no;
5b2fd956 1022}
dea4562b
JH
1023
1024static int rerere_forget_one_path(const char *path, struct string_list *rr)
1025{
1026 const char *filename;
1d51eced 1027 struct rerere_id *id;
dea4562b
JH
1028 unsigned char sha1[20];
1029 int ret;
8d9b5a4a 1030 struct string_list_item *item;
dea4562b 1031
963ec003
JH
1032 /*
1033 * Recreate the original conflict from the stages in the
1034 * index and compute the conflict ID
1035 */
dea4562b
JH
1036 ret = handle_cache(path, sha1, NULL);
1037 if (ret < 1)
1038 return error("Could not parse conflict hunks in '%s'", path);
963ec003
JH
1039
1040 /* Nuke the recorded resolution for the conflict */
1d51eced 1041 id = new_rerere_id(sha1);
890fca84
JH
1042
1043 for (id->variant = 0;
1044 id->variant < id->collection->status_nr;
1045 id->variant++) {
1046 mmfile_t cur = { NULL, 0 };
1047 mmbuffer_t result = {NULL, 0};
1048 int cleanly_resolved;
1049
1050 if (!has_rerere_resolution(id))
1051 continue;
1052
1053 handle_cache(path, sha1, rerere_path(id, "thisimage"));
1054 if (read_mmfile(&cur, rerere_path(id, "thisimage"))) {
1055 free(cur.ptr);
8f449614
JH
1056 error("Failed to update conflicted state in '%s'", path);
1057 goto fail_exit;
890fca84
JH
1058 }
1059 cleanly_resolved = !try_merge(id, path, &cur, &result);
1060 free(result.ptr);
1061 free(cur.ptr);
1062 if (cleanly_resolved)
1063 break;
1064 }
1065
8f449614
JH
1066 if (id->collection->status_nr <= id->variant) {
1067 error("no remembered resolution for '%s'", path);
1068 goto fail_exit;
1069 }
890fca84 1070
18bb9934 1071 filename = rerere_path(id, "postimage");
8f449614
JH
1072 if (unlink(filename)) {
1073 if (errno == ENOENT)
1074 error("no remembered resolution for %s", path);
1075 else
ec34a8b1 1076 error_errno("cannot unlink %s", filename);
8f449614 1077 goto fail_exit;
d9d501b0 1078 }
dea4562b 1079
963ec003
JH
1080 /*
1081 * Update the preimage so that the user can resolve the
1082 * conflict in the working tree, run us again to record
1083 * the postimage.
1084 */
18bb9934 1085 handle_cache(path, sha1, rerere_path(id, "preimage"));
dea4562b
JH
1086 fprintf(stderr, "Updated preimage for '%s'\n", path);
1087
963ec003
JH
1088 /*
1089 * And remember that we can record resolution for this
1090 * conflict when the user is done.
1091 */
8d9b5a4a 1092 item = string_list_insert(rr, path);
1d51eced 1093 free_rerere_id(item);
18bb9934 1094 item->util = id;
dea4562b
JH
1095 fprintf(stderr, "Forgot resolution for %s\n", path);
1096 return 0;
8f449614
JH
1097
1098fail_exit:
1099 free(id);
1100 return -1;
dea4562b
JH
1101}
1102
01a10b0a 1103int rerere_forget(struct pathspec *pathspec)
dea4562b
JH
1104{
1105 int i, fd;
183113a5
TF
1106 struct string_list conflict = STRING_LIST_INIT_DUP;
1107 struct string_list merge_rr = STRING_LIST_INIT_DUP;
dea4562b
JH
1108
1109 if (read_cache() < 0)
1110 return error("Could not read index");
1111
6751e047 1112 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
0544574c
JK
1113 if (fd < 0)
1114 return 0;
dea4562b 1115
963ec003
JH
1116 /*
1117 * The paths may have been resolved (incorrectly);
1118 * recover the original conflicted state and then
1119 * find the conflicted paths.
1120 */
dea4562b
JH
1121 unmerge_cache(pathspec);
1122 find_conflict(&conflict);
1123 for (i = 0; i < conflict.nr; i++) {
1124 struct string_list_item *it = &conflict.items[i];
6d2df284 1125 if (!match_pathspec(&the_index, pathspec, it->string,
ae8d0824 1126 strlen(it->string), 0, NULL, 0))
dea4562b
JH
1127 continue;
1128 rerere_forget_one_path(it->string, &merge_rr);
1129 }
1130 return write_rr(&merge_rr, fd);
1131}
0f891e7d 1132
e828de82
JH
1133/*
1134 * Garbage collection support
1135 */
1d51eced 1136
5ea82279 1137static timestamp_t rerere_created_at(struct rerere_id *id)
0f891e7d
JH
1138{
1139 struct stat st;
1d51eced 1140
18bb9934 1141 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
0f891e7d
JH
1142}
1143
5ea82279 1144static timestamp_t rerere_last_used_at(struct rerere_id *id)
0f891e7d
JH
1145{
1146 struct stat st;
1d51eced 1147
18bb9934 1148 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
0f891e7d
JH
1149}
1150
e828de82
JH
1151/*
1152 * Remove the recorded resolution for a given conflict ID
1153 */
1d51eced 1154static void unlink_rr_item(struct rerere_id *id)
0f891e7d 1155{
1be1e851
JH
1156 unlink_or_warn(rerere_path(id, "thisimage"));
1157 remove_variant(id);
1158 id->collection->status[id->variant] = 0;
1159}
1160
5ea82279
JH
1161static void prune_one(struct rerere_id *id,
1162 timestamp_t cutoff_resolve, timestamp_t cutoff_noresolve)
1be1e851 1163{
5ea82279
JH
1164 timestamp_t then;
1165 timestamp_t cutoff;
1be1e851
JH
1166
1167 then = rerere_last_used_at(id);
1168 if (then)
1169 cutoff = cutoff_resolve;
1170 else {
1171 then = rerere_created_at(id);
1172 if (!then)
1173 return;
1174 cutoff = cutoff_noresolve;
1175 }
5ea82279 1176 if (then < cutoff)
1be1e851 1177 unlink_rr_item(id);
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1178}
1179
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1180void rerere_gc(struct string_list *rr)
1181{
1182 struct string_list to_remove = STRING_LIST_INIT_DUP;
1183 DIR *dir;
1184 struct dirent *e;
1be1e851 1185 int i;
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1186 timestamp_t now = time(NULL);
1187 timestamp_t cutoff_noresolve = now - 15 * 86400;
1188 timestamp_t cutoff_resolve = now - 60 * 86400;
0f891e7d 1189
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1190 if (setup_rerere(rr, 0) < 0)
1191 return;
1192
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1193 git_config_get_expiry_in_days("gc.rerereresolved", &cutoff_resolve, now);
1194 git_config_get_expiry_in_days("gc.rerereunresolved", &cutoff_noresolve, now);
633e5ad3 1195 git_config(git_default_config, NULL);
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1196 dir = opendir(git_path("rr-cache"));
1197 if (!dir)
1198 die_errno("unable to open rr-cache directory");
e828de82 1199 /* Collect stale conflict IDs ... */
0f891e7d 1200 while ((e = readdir(dir))) {
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1201 struct rerere_dir *rr_dir;
1202 struct rerere_id id;
1203 int now_empty;
1204
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1205 if (is_dot_or_dotdot(e->d_name))
1206 continue;
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1207 rr_dir = find_rerere_dir(e->d_name);
1208 if (!rr_dir)
1209 continue; /* or should we remove e->d_name? */
1210
1211 now_empty = 1;
1212 for (id.variant = 0, id.collection = rr_dir;
1213 id.variant < id.collection->status_nr;
1214 id.variant++) {
5ea82279 1215 prune_one(&id, cutoff_resolve, cutoff_noresolve);
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1216 if (id.collection->status[id.variant])
1217 now_empty = 0;
0f891e7d 1218 }
1be1e851 1219 if (now_empty)
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1220 string_list_append(&to_remove, e->d_name);
1221 }
a9930e35 1222 closedir(dir);
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1223
1224 /* ... and then remove the empty directories */
0f891e7d 1225 for (i = 0; i < to_remove.nr; i++)
1be1e851 1226 rmdir(git_path("rr-cache/%s", to_remove.items[i].string));
0f891e7d 1227 string_list_clear(&to_remove, 0);
9dd330e6 1228 rollback_lock_file(&write_lock);
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1229}
1230
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1231/*
1232 * During a conflict resolution, after "rerere" recorded the
1233 * preimages, abandon them if the user did not resolve them or
1234 * record their resolutions. And drop $GIT_DIR/MERGE_RR.
1235 *
1236 * NEEDSWORK: shouldn't we be calling this from "reset --hard"?
1237 */
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1238void rerere_clear(struct string_list *merge_rr)
1239{
1240 int i;
1241
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1242 if (setup_rerere(merge_rr, 0) < 0)
1243 return;
1244
0f891e7d 1245 for (i = 0; i < merge_rr->nr; i++) {
1d51eced 1246 struct rerere_id *id = merge_rr->items[i].util;
1be1e851 1247 if (!has_rerere_resolution(id)) {
18bb9934 1248 unlink_rr_item(id);
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1249 rmdir(rerere_path(id, NULL));
1250 }
0f891e7d 1251 }
102de880 1252 unlink_or_warn(git_path_merge_rr(the_repository));
9dd330e6 1253 rollback_lock_file(&write_lock);
0f891e7d 1254}