Comment explaining how 'git fat checkout' forces resmudging

1 files changed, 7 insertions, 0 deletions

diff --git a/git-fat b/git-fat
index b2ec8d7..e963a7e 100755
--- a/git-fat
+++ b/git-fat
@@ -205,7 +205,14 @@ class GitFat(object):
             objpath = os.path.join(self.objdir, digest)
             if os.access(objpath, os.R_OK):
                 print('Restoring %s -> %s' % (digest, fname))
+                # The output of our smudge filter depends on the existence of
+                # the file in .git/fat/objects, but git caches the file stat
+                # from the previous time the file was smudged, therefore it
+                # won't try to re-smudge. I don't know a git command that
+                # specifically invalidates that cache, but touching the file
+                # also does the trick.
                 os.utime(fname, None)
+                # This re-smudge is essentially a copy that restores permissions.
                 subprocess.check_call(['git', 'checkout-index', '--index', '--force', fname])
             elif show_orphans:
                 print('Data unavailable: %s %s' % (digest,fname))