[PATCH 1/3] Don't diff empty tree on branch creation in paranoid update hook

Listing all files in a branch during branch creation is silly;
the user's file-level ACLs probably don't mean anything at this
point.  We now treat the base case of 0{40} as an empty diff,
as this happens only when the user is creating the branch and
there are file level ACLs that diff against the old value of
the branch.

Signed-off-by: Shawn O. Pearce <redacted>
---

 I had this series of 3 patches laying around that I forgot to send.
 They have been in production for a while (~5 months) and are
 safe to apply.  Funny what you find laying around in your topic
 branches sometimes...

 contrib/hooks/update-paranoid |   14 ++++++--------
 1 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/contrib/hooks/update-paranoid b/contrib/hooks/update-paranoid
index 068fa37..6e0d97c 100644
--- a/contrib/hooks/update-paranoid
+++ b/contrib/hooks/update-paranoid

@@ -225,14 +225,12 @@ sub load_diff ($) {
 		local $/ = "\0";
 		my %this_diff;
 		if ($base =~ /^0{40}$/) {
-			open(T,'-|','git','ls-tree',
-				'-r','--name-only','-z',
-				$new) or return undef;
-			while (<T>) {
-				chop;
-				$this_diff{$_} = 'A';
-			}
-			close T or return undef;
+			# Don't load the diff at all; we are making the
+			# branch and have no base to compare to in this
+			# case.  A file level ACL makes no sense in this
+			# context.  Having an empty diff will allow the
+			# branch creation.
+			#
 		} else {
 			open(T,'-|','git','diff-tree',
 				'-r','--name-status','-z',

-- 
1.5.5.1.501.gefb4