Thread (10 messages) flat view 10 messages, 3 authors, 2019-06-16

Re: [PATCH] completion: do not cache if --git-completion-helper fails

From: SZEDER Gábor <hidden>
Date: 2019-06-07 10:03:01

On Fri, Jun 07, 2019 at 04:30:34PM +0700, Nguyễn Thái Ngọc Duy wrote:
"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.
I think a permanently failing 'git cmd --git-completion-helper'
shouldn't really happen, unless there is a bug in the completion
script or the git installation or similar exceptional situation.  And
then that issue should be fixed, but I don't think we should worry
about an extra subshell and git process in those situations.
quoted hunk ↗ jump to hunk
(*) 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 <redacted>
Signed-off-by: Nguyễn Thái Ngọc Duy <redacted>
---
 contrib/completion/git-completion.bash | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 9f71bcde96..a515de8501 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -398,13 +398,15 @@ __gitcomp_builtin ()
 	eval "options=\$$var"
 
 	if [ -z "$options" ]; then
+		local nocache=
 		# 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) " || nocache=t
Why not just 'return' here?

If we return, then it won't list any options, and the shell should fall
back to regular file completion.  With this patch it will still list
extra options, if there are any, and I don't really see the point in
doing that.

+
 		for i in $excl; do
 			options="${options/ $i / }"
 		done
-		eval "$var=\"$options\""
+		test -n "$nocache" || eval "$var=\"$options\""
 	fi
 
 	__gitcomp "$options"
-- 
2.22.0.rc0.322.g2b0371e29a
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