@matheusbsbs / matheus-bagliano / commits / b74c90fb41

read_cache: roll back lock in `update_index_if_able()`

`update_index_if_able()` used to always commit the lock or roll it back. Commit 03b866477 (read-cache: new API write_locked_index instead of write_index/write_cache, 2014-06-13) stopped rolling it back in case a write was not even attempted. This change in behavior is not motivated in the commit message and appears to be accidental: the `else`-path was removed, although that changed the behavior in case the `if` shortcuts. Reintroduce the rollback and document this behavior. While at it, move the documentation on this function from the function definition to the function declaration in cache.h. If `write_locked_index(..., COMMIT_LOCK)` fails, it will roll back the lock for us (see the previous commit). Noticed-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Martin Ågren committed Oct 6, 2017 at 22:12 UTC b74c90fb419b002c664b0236f2941c34786b18b9
2 files changed +6 -3
cache.h
+4
@@ -734,6 +734,10 @@ extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
734 extern int refresh_index(struct index_state *, unsigned int flags, const struct pathspec *pathspec, char *seen, const char *header_msg);
735 extern struct cache_entry *refresh_cache_entry(struct cache_entry *, unsigned int);
736
737 +/*
738 + * Opportunistically update the index but do not complain if we can't.
739 + * The lockfile is always committed or rolled back.
740 + */
741 extern void update_index_if_able(struct index_state *, struct lock_file *);
742
743 extern int hold_locked_index(struct lock_file *, int);
read-cache.c
+2 -3
@@ -2176,14 +2176,13 @@ static int has_racy_timestamp(struct index_state *istate)
2176 return 0;
2177 }
2178
2179 -/*
2180 - * Opportunistically update the index but do not complain if we can't
2181 - */
2179 void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
2180 {
2181 if ((istate->cache_changed || has_racy_timestamp(istate)) &&
2182 verify_index(istate))
2183 write_locked_index(istate, lockfile, COMMIT_LOCK);
2184 + else
2185 + rollback_lock_file(lockfile);
2186 }
2187
2188 /*