ARGF does more than we want

ARGF is a virtual IO stream that treats the elements of ARGV as paths
to files to be opened. In practice, git-receive-pack will probably
never pass arguments to pre-receive and post-receive because it is not
supposed to (according to 'man 5 githooks'). In case it does, however
our hooks should not have the surprise behavior of treating those
arguments as files to be opened.

hooks/post-receive

@@ -3,7 +3,7 @@
 # This file was placed here by GitLab. It makes sure that your pushed commits
 # will be processed properly.
 
-refs = ARGF.read
+refs = $stdin.read
 key_id  = ENV['GL_ID']
 repo_path = Dir.pwd
 

hooks/pre-receive

@@ -3,7 +3,7 @@
 # This file was placed here by GitLab. It makes sure that your pushed commits
 # will be processed properly.
 
-refs = ARGF.read
+refs = $stdin.read
 key_id  = ENV['GL_ID']
 repo_path = Dir.pwd