core.fsync: new option to harden the index

This commit introduces the new ability for the user to harden
the index. In the event of a system crash, the index must be
durable for the user to actually find a file that has been added
to the repo and then deleted from the working tree.

We use the presence of the COMMIT_LOCK flag and absence of the
alternate_index_output as a proxy for determining whether we're
updating the persistent index of the repo or some temporary
index. We don't sync these temporary indexes.

Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/config.c b/config.c
index 94a4598b5f..80f33c9198 100644
--- a/config.c
+++ b/config.c
@@ -1331,6 +1331,7 @@ static const struct fsync_component_name {
 	{ "pack", FSYNC_COMPONENT_PACK },
 	{ "pack-metadata", FSYNC_COMPONENT_PACK_METADATA },
 	{ "commit-graph", FSYNC_COMPONENT_COMMIT_GRAPH },
+	{ "index", FSYNC_COMPONENT_INDEX },
 };
 
 static enum fsync_component parse_fsync_components(const char *var, const char *string)