"Assume unchanged" git: do not set CE_VALID with --refresh

When working with automatic assume-unchanged mode using
core.ignorestat, setting CE_VALID after --refresh makes things
more cumbersome to use.  Consider this scenario:

(1) the working tree is on a filesystem with slow lstat(2).
The user sets core.ignorestat = true.

(2) "git checkout" to switch to a different branch (or initial
checkout) updates all paths and the index starts out with
"all clean".

(3) The user knows she wants to edit certain paths.  She uses
update-index --no-assume-unchanged (we could call it --edit;
the name is inmaterial) to mark these paths and starts
editing.

(4) After editing half of the paths marked to be edited, she
runs "git status".  This runs "update-index --refresh" to
reduce the false hits from diff-files.

(5) Now the other half of the paths, since she has not changed
them, are found to match the index, and CE_VALID is set on
them again.

For this reason, this commit makes update-index --refresh not to
set CE_VALID even after the path without CE_VALID are verified
to be up to date.  The user still can run --really-refresh to
force lstat() to match the index entries to the reality.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/update-index.c b/update-index.c
index 767fd49721b26eb6c48d8dc77e5f83d2364eae28..bb730509b871381ffbd8457bd38ce940d78ba50d 100644 (file)
--- a/update-index.c
+++ b/update-index.c
@@ -172,6 +172,15 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce, int really)
        memcpy(updated, ce, size);
        fill_stat_cache_info(updated, &st);
 
+       /* In this case, if really is not set, we should leave
+        * CE_VALID bit alone.  Otherwise, paths marked with
+        * --no-assume-unchanged (i.e. things to be edited) will
+        * reacquire CE_VALID bit automatically, which is not
+        * really what we want.
+        */
+       if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID)))
+               updated->ce_flags &= ~htons(CE_VALID);
+
        return updated;
 }