Change {pre,post}-receive hooks to use stdin

Sergey Vlasov, Andy Parkins and Alex Riesen all pointed out that it
is possible for a single invocation of receive-pack to be given more
refs than the OS might allow us to pass as command line parameters
to a single hook invocation.

We don't want to break these up into multiple invocations (like
xargs might do) as that makes it impossible for the pre-receive
hook to verify multiple related ref updates occur at the same time,
and it makes it harder for post-receive to send out a single batch
notification.

Instead we pass the reference data on a pipe connected to the
hook's stdin, supplying one ref per line to the hook.  This way a
single hook invocation can obtain an infinite amount of ref data,
without bumping into any operating system limits.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 16 insertions, 14 deletions

diff --git a/t/t5401-update-hooks.sh b/t/t5401-update-hooks.sh
index cf6306c..f1c7ff0 100755
--- a/t/t5401-update-hooks.sh
+++ b/t/t5401-update-hooks.sh
@@ -25,8 +25,8 @@ test_expect_success setup '
 
 cat >victim/.git/hooks/pre-receive <<'EOF'
 #!/bin/sh
-echo "$@" >>$GIT_DIR/pre-receive.args
-read x; printf "$x" >$GIT_DIR/pre-receive.stdin
+printf "$@" >>$GIT_DIR/pre-receive.args
+cat - >$GIT_DIR/pre-receive.stdin
 echo STDOUT pre-receive
 echo STDERR pre-receive >&2
 EOF
@@ -44,8 +44,8 @@ chmod u+x victim/.git/hooks/update
 
 cat >victim/.git/hooks/post-receive <<'EOF'
 #!/bin/sh
-echo "$@" >>$GIT_DIR/post-receive.args
-read x; printf "$x" >$GIT_DIR/post-receive.stdin
+printf "$@" >>$GIT_DIR/post-receive.args
+cat - >$GIT_DIR/post-receive.stdin
 echo STDOUT post-receive
 echo STDERR post-receive >&2
 EOF
@@ -80,11 +80,10 @@ test_expect_success 'hooks ran' '
 	test -f victim/.git/post-update.stdin
 '
 
-test_expect_success 'pre-receive hook arguments' '
-	echo \
-	 refs/heads/master $commit0 $commit1 \
-	 refs/heads/tofail $commit1 $commit0 \
-	| git diff - victim/.git/pre-receive.args
+test_expect_success 'pre-receive hook input' '
+	(echo $commit0 $commit1 refs/heads/master;
+	 echo $commit1 $commit0 refs/heads/tofail
+	) | git diff - victim/.git/pre-receive.stdin
 '
 
 test_expect_success 'update hook arguments' '
@@ -93,9 +92,9 @@ test_expect_success 'update hook arguments' '
 	) | git diff - victim/.git/update.args
 '
 
-test_expect_success 'post-receive hook arguments' '
-	echo refs/heads/master $commit0 $commit1 |
-	git diff - victim/.git/post-receive.args
+test_expect_success 'post-receive hook input' '
+	echo $commit0 $commit1 refs/heads/master |
+	git diff - victim/.git/post-receive.stdin
 '
 
 test_expect_success 'post-update hook arguments' '
@@ -104,12 +103,15 @@ test_expect_success 'post-update hook arguments' '
 '
 
 test_expect_success 'all hook stdin is /dev/null' '
-	! test -s victim/.git/pre-receive.stdin &&
 	! test -s victim/.git/update.stdin &&
-	! test -s victim/.git/post-receive.stdin &&
 	! test -s victim/.git/post-update.stdin
 '
 
+test_expect_success 'all *-receive hook args are empty' '
+	! test -s victim/.git/pre-receive.args &&
+	! test -s victim/.git/post-receive.args
+'
+
 test_expect_failure 'send-pack produced no output' '
 	test -s send.out
 '