[PATCH v2] git-prompt: preserve value of $? inside shell prompt

From: Tony Finch <dot@dotat.at>
Date: Dec 22, 2014, 18:09 UTC
Message-ID: <alpine.LSU.2.00.1412221808110.2546@hermes-1.csi.cam.ac.uk>
In-Reply-To: <xmqqa92fbo0j.fsf@gitster.dls.corp.google.com>

If you have a prompt which displays the command exit status, __git_ps1 without this change corrupts it, although it has the correct value in the parent shell:

	~/src/git (master) 0 $ set | grep ^PS1
	PS1='\w$(__git_ps1) $? \$ '
	~/src/git (master) 0 $ false
	~/src/git (master) 0 $ echo $?
	1
	~/src/git (master) 0 $

There is a slightly ugly workaround:

	~/src/git (master) 0 $ set | grep ^PS1
	PS1='\w$(x=$?; __git_ps1; exit $x) $? \$ '
	~/src/git (master) 0 $ false
	~/src/git (master) 1 $

This change makes the workaround unnecessary.

Signed-off-by: Tony Finch <dot@dotat.at>
---
 contrib/completion/git-prompt.sh | 4 ++++
 1 file changed, 4 insertions(+)

I hope that explains it properly :-)

diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index c5473dc..5fe69d0 100644
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -288,6 +288,7 @@ __git_eread ()
 # In this mode you can request colored hints using GIT_PS1_SHOWCOLORHINTS=true
 __git_ps1 ()
 {
+	local exit=$?
 	local pcmode=no
 	local detached=no
 	local ps1pc_start='\u@\h:\w '
@@ -511,4 +512,7 @@ __git_ps1 ()
 	else
 		printf -- "$printf_format" "$gitstring"
 	fi
+
+	# preserve exit status
+	return $exit
 }

-- 
2.2.1.68.g56d9796