Re: [RFC/PATCH] git-completion.bash: remove bashism to fix ZSH compatibility

[Junio C Hamano <gitster@pobox.com>]

Manlio Perillo <manlio.perillo@gmail.com> writes:

> Yes, I was plainning to send another patch to fix this (and your other
> suggestion regarding the CDPATH environment variable, if I remember
> correctly),...

Ahh, thanks for reminding me of this.  You are right; these two
functions are broken when the user has CDPATH set, I think.

Here is a reroll.

-- >8 --
From: Matthieu Moy <Matthieu.Moy@imag.fr>
Date: Mon, 11 Mar 2013 13:21:27 +0100
Subject: [PATCH] git-completion.bash: zsh does not implement function
 redirection correctly

A recent change added functions whose entire standard error stream
is redirected to /dev/null using a construct that is valid POSIX.1
but is not widely used:

	funcname () {
		cd "$1" && run some command "$2"
	} 2>/dev/null

Even though this file is "git-completion.bash", zsh completion
support dot-sources it (instead of asking bash to grok it like tcsh
completion does), and zsh does not implement this redirection
correctly.

With zsh, trying to complete an inexistant directory gave this:

  git add no-such-dir/__git_ls_files_helper:cd:2: no such file or directory: no-such-dir/

Also these functions use "cd" to first go somewhere else before
running a command, but the location the caller wants them to go that
is given as an argument to them should not be affected by CDPATH
variable the users may have set for their interactive session.

To fix both of these, wrap the body of the function in a subshell,
unset CDPATH at the beginning of the subshell, and redirect the
standard error stream of the subshell to /dev/null.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 contrib/completion/git-completion.bash | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 51b8b3b..430566d 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -299,9 +299,12 @@ __git_index_file_list_filter ()
 # the second argument.
 __git_ls_files_helper ()
 {
-	# NOTE: $2 is not quoted in order to support multiple options
-	cd "$1" && git ls-files --exclude-standard $2
-} 2>/dev/null
+	(
+		test -n "${CDPATH+set}" && unset CDPATH
+		# NOTE: $2 is not quoted in order to support multiple options
+		cd "$1" && git ls-files --exclude-standard $2
+	) 2>/dev/null
+}
 
 
 # Execute git diff-index, returning paths relative to the directory
@@ -309,8 +312,11 @@ __git_ls_files_helper ()
 # specified in the second argument.
 __git_diff_index_helper ()
 {
-	cd "$1" && git diff-index --name-only --relative "$2"
-} 2>/dev/null
+	(
+		test -n "${CDPATH+set}" && unset CDPATH
+		cd "$1" && git diff-index --name-only --relative "$2"
+	) 2>/dev/null
+}
 
 # __git_index_files accepts 1 or 2 arguments:
 # 1: Options to pass to ls-files (required).
-- 
1.8.2-rc3-219-ge56455f