request-pull: protect against OPTIONS_KEEPDASHDASH from environment

Like most git commands, request-pull supports a -- delimiter to allow
callers to pass arguments that would otherwise be treated as an option
afterwards.  The internal OPTIONS_KEEPDASHDASH variable is passed
empty to git-sh-setup to indicate that request-pull itself does not
care about the position of the -- delimiter.  But if the user has
that variable in her environment, request-pull will see the “--” and
fail.

Empty it explicitly to guard against this.  While at it, make the
corresponding fix to git-resurrect, too (all other scripts in git.git
already protect themselves).

Acked-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/git-resurrect.sh

@@ -9,6 +9,7 @@ other/Merge <other> into <name> (respectively) commit subjects, which
 is rather slow but allows you to resurrect other people's topic
 branches."
 
+OPTIONS_KEEPDASHDASH=
 OPTIONS_SPEC="\
 git resurrect $USAGE
 --

git-request-pull.sh

@@ -8,6 +8,7 @@ USAGE='<start> <url> [<end>]'
 LONG_USAGE='Summarizes the changes between two commits to the standard output,
 and includes the given URL in the generated summary.'
 SUBDIRECTORY_OK='Yes'
+OPTIONS_KEEPDASHDASH=
 OPTIONS_SPEC='git request-pull [options] start url [end]
 --
 p    show patch text as well

t/t5150-request-pull.sh

@@ -211,4 +211,18 @@ test_expect_success 'pull request format' '
 
 '
 
+test_expect_success 'request-pull ignores OPTIONS_KEEPDASHDASH poison' '
+
+	(
+		cd local &&
+		OPTIONS_KEEPDASHDASH=Yes &&
+		export OPTIONS_KEEPDASHDASH &&
+		git checkout initial &&
+		git merge --ff-only master &&
+		git push origin master:for-upstream &&
+		git request-pull -- initial "$downstream_url" >../request
+	)
+
+'
+
 test_done