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git/rerere.h

47 lines
1.4 KiB

#ifndef RERERE_H
#define RERERE_H
#include "string-list.h"
struct pathspec;
struct repository;
#define RERERE_AUTOUPDATE 01
#define RERERE_NOAUTOUPDATE 02
rerere: release lockfile in non-writing functions There's a bug in builtin/am.c in which we take a lock on MERGE_RR recursively. But rather than fix am.c, this patch fixes the confusing interface from rerere.c that caused the bug. Read on for the gory details. The setup_rerere() function both reads the existing MERGE_RR file, and takes MERGE_RR.lock. In the rerere() and rerere_forget() functions, we end up in write_rr(), which will then commit the lock file. But for functions like rerere_clear() that do not write to MERGE_RR, we expect the caller to have handled setup_rerere(). That caller would then need to release the lockfile, but it can't; the lock struct is local to rerere.c. For builtin/rerere.c, this is OK. We run a single rerere operation and then exit immediately, which has the side effect of rolling back the lockfile. But in builtin/am.c, this is actively wrong. If we run "git am -3 --skip", we call setup-rerere twice without releasing the lock: 1. The "--skip" causes us to call am_rerere_clear(), which calls setup_rerere(), but never drops the lock. 2. We then proceed to the next patch. 3. The "--3way" may cause us to call rerere() to handle conflicts in that patch, but we are already holding the lock. The lockfile code dies with: BUG: prepare_tempfile_object called for active object We could fix this by having rerere_clear() call rollback_lock_file(). But it feels a bit odd for it to roll back a lockfile that it did not itself take. So let's simplify the interface further, and handle setup_rerere in the function itself, taking away the question from the caller over whether they need to do so. We can give rerere_gc() the same treatment, as well (even though it doesn't have any callers besides builtin/rerere.c at this point). Note that these functions don't take flags from their callers to pass along to setup_rerere; that's OK, because the flags would not be meaningful for what they are doing. Both of those functions need to hold the lock because even though they do not write to MERGE_RR, they are still writing and should be protected from a simultaneous "rerere" run. But rerere_remaining(), "rerere diff", and "rerere status" are all read-only operations. They want to setup_rerere(), but do not care about taking the lock in the first place. Since our update of MERGE_RR is the usual atomic rename done by commit_lock_file, they can just do a lockless read. For that, we teach setup_rerere a READONLY flag to avoid the lock. As a bonus, this pushes builtin/rerere.c's setup_rerere call closer to the functions that use it. Which means that "git rerere totally-bogus-command" will no longer silently exit(0) in a repository without rerere enabled. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
7 years ago
#define RERERE_READONLY 04
/*
* Marks paths that have been hand-resolved and added to the
* index. Set in the util field of such paths after calling
* rerere_remaining.
*/
extern void *RERERE_RESOLVED;
struct rerere_dir;
struct rerere_id {
struct rerere_dir *collection;
int variant;
};
int setup_rerere(struct repository *,struct string_list *, int);
#ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
#define rerere(flags) repo_rerere(the_repository, flags)
#endif
int repo_rerere(struct repository *, int);
/*
* Given the conflict ID and the name of a "file" used for replaying
* the recorded resolution (e.g. "preimage", "postimage"), return the
* path to that filesystem entity. With "file" specified with NULL,
* return the path to the directory that houses these files.
*/
const char *rerere_path(const struct rerere_id *, const char *file);
int rerere_forget(struct repository *, struct pathspec *);
int rerere_remaining(struct repository *, struct string_list *);
void rerere_clear(struct repository *, struct string_list *);
void rerere_gc(struct repository *, struct string_list *);
#define OPT_RERERE_AUTOUPDATE(v) OPT_UYN(0, "rerere-autoupdate", (v), \
N_("update the index with reused conflict resolution if possible"))
#endif