[PATCH 17/19] bash prompt: use bash builtins to check stash state

["SZEDER Gábor" <szeder@ira.uka.de>]

When the environment variable $GIT_PS1_SHOWSTASHSTATE is set
__git_ps1() checks the presence of stashes by running 'git rev-parse
--verify refs/stash'.  This command not only checks that the
'refs/stash' ref exists but also, well, verifies that it's a valid
ref.

However, we don't need to be that thorough for the bash prompt.  We
can omit that verification and only check whether 'refs/stash' exists
or not.  Since 'git pack-refs' never packs 'refs/stash', it's a matter
of checking the existence of a ref file.  Perform this check using
only bash builtins to spare the overhead of fork()+exec()ing a git
process.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
---
 contrib/completion/git-completion.bash | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 64207e3c..c4feab68 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -356,7 +356,9 @@ __git_ps1 ()
 	fi
 
 	if [ -n "${GIT_PS1_SHOWSTASHSTATE-}" ]; then
-	        git rev-parse --verify refs/stash >/dev/null 2>&1 && s="$"
+		if [ -r "$__git_dir/refs/stash" ]; then
+			s="$"
+		fi
 	fi
 
 	if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
-- 
1.7.10.1.541.gb1be298