[PATCH] Re-instate index file write optimization

This makes "git-update-index" avoid the new index file write if it didn't
make any changes to the index.

It still doesn't make things like "git status" be read-only operations in
general, but if the index file doesn't need refreshing, it now will at
least avoid making unnecessary changes.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/update-index.c b/update-index.c
index ade1ee7..b825a11 100644 (file)
--- a/update-index.c
+++ b/update-index.c
@@ -391,9 +391,11 @@ int main(int argc, const char **argv)
                        update_one(buf.buf, prefix, prefix_length);
                }
        }
-       if (write_cache(newfd, active_cache, active_nr) ||
-           commit_index_file(&cache_file))
-               die("Unable to write new cachefile");
+       if (active_cache_changed) {
+               if (write_cache(newfd, active_cache, active_nr) ||
+                   commit_index_file(&cache_file))
+                       die("Unable to write new cachefile");
+       }
 
        return has_errors ? 1 : 0;
 }