completion: do not cache if --git-completion-helper fails

"git <cmd> --git-completion-helper" could fail if the command checks for
a repo before parse_options(). If the result is cached, later on when
the user moves to a worktree with repo, tab completion will still fail.

Avoid this by detecting errors and not cache the completion output.

0001-completion-do-not-cache-if-git-completion-helper-fai.patch

@@ -0,0 +1,51 @@
+From 69702523afb4de692b415648e53fcfb1b4630f18 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?=
+ <pclouds@gmail.com>
+Date: Wed, 12 Jun 2019 15:56:06 +0700
+Subject: [PATCH] completion: do not cache if --git-completion-helper fails
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+"git <cmd> --git-completion-helper" could fail if the command checks for
+a repo before parse_options(). If the result is cached, later on when
+the user moves to a worktree with repo, tab completion will still fail.
+
+Avoid this by detecting errors and not cache the completion output. We
+can try again and hopefully succeed next time (e.g. when a repo is
+found).
+
+Of course if --git-completion-helper fails permanently because of other
+reasons (*), this will slow down completion. But I don't see any better
+option to handle that case.
+
+(*) one of those cases is if __gitcomp_builtin is called on a command
+  that does not support --git-completion-helper. And we do have a
+  generic call
+
+    __git_complete_common "$command"
+
+  but this case is protected with __git_support_parseopt_helper so we're
+  good.
+
+Reported-by: Felipe Contreras <felipe.contreras@gmail.com>
+Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ contrib/completion/git-completion.bash | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
+index 499e56f83d0a0..00cc695e3d748 100644
+--- a/contrib/completion/git-completion.bash
++++ b/contrib/completion/git-completion.bash
+@@ -400,7 +400,8 @@ __gitcomp_builtin ()
+ 	if [ -z "$options" ]; then
+ 		# leading and trailing spaces are significant to make
+ 		# option removal work correctly.
+-		options=" $incl $(__git ${cmd/_/ } --git-completion-helper) "
++		options=" $incl $(__git ${cmd/_/ } --git-completion-helper) " || return
++
+ 		for i in $excl; do
+ 			options="${options/ $i / }"
+ 		done

git.spec

@@ -88,7 +88,7 @@
 
 Name:           git
 Version:        2.22.0
-Release:        1%{?rcrev}%{?dist}.1
+Release:        2%{?rcrev}%{?dist}
 Summary:        Fast Version Control System
 License:        GPLv2
 URL:            https://git-scm.com/
@@ -120,6 +120,11 @@ Source99:       print-failed-test-output
 # https://bugzilla.redhat.com/490602
 Patch0:         git-cvsimport-Ignore-cvsps-2.2b1-Branches-output.patch
 
+# Don't cache completion results if --git-completion-helper fails
+# https://public-inbox.org/git/20190612085606.12144-1-pclouds@gmail.com/
+# https://github.com/gitster/git/commit/69702523a.patch
+Patch1:         0001-completion-do-not-cache-if-git-completion-helper-fai.patch
+
 %if %{with docs}
 # pod2man is needed to build Git.3pm
 BuildRequires:  %{_bindir}/pod2man
@@ -956,6 +961,9 @@ rmdir --ignore-fail-on-non-empty "$testdir"
 %{?with_docs:%{_pkgdocdir}/git-svn.html}
 
 %changelog
+* Thu Jul 25 2019 Todd Zullinger <tmz@pobox.com> - 2.22.0-2
+- completion: do not cache if --git-completion-helper fails
+
 * Thu Jul 25 2019 Fedora Release Engineering <releng@fedoraproject.org> - 2.22.0-1.1
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild