stash: remove the stash.useBuiltin setting

Remove the stash.useBuiltin setting which was added as an escape hatch
to disable the builtin version of stash first released with Git 2.22.

Carrying the legacy version is a maintenance burden, and has in fact
become out of date failing a test since the 2.23 release, without
anyone noticing until now.  So users would be getting a hint to fall
back to a potentially buggy version of the tool.

We used to shell out to git config to get the useBuiltin configuration
to avoid changing any global state before spawning legacy-stash.
However that is no longer necessary, so just use the 'git_config'
function to get the setting instead.

Similar to what we've done in d03ebd411c ("rebase: remove the
rebase.useBuiltin setting", 2019-03-18), where we remove the
corresponding setting for rebase, we leave the documentation in place,
so people can refer back to it when searching for it online, and so we
can refer to it in the commit message.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index ea56e85..b84d55a 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -1285,4 +1285,18 @@ test_expect_success 'stash handles skip-worktree entries nicely' '
 	git rev-parse --verify refs/stash:A.t
 '
 
+test_expect_success 'stash -c stash.useBuiltin=false warning ' '
+	expected="stash.useBuiltin support has been removed" &&
+
+	git -c stash.useBuiltin=false stash 2>err &&
+	test_i18ngrep "$expected" err &&
+	env GIT_TEST_STASH_USE_BUILTIN=false git stash 2>err &&
+	test_i18ngrep "$expected" err &&
+
+	git -c stash.useBuiltin=true stash 2>err &&
+	test_must_be_empty err &&
+	env GIT_TEST_STASH_USE_BUILTIN=true git stash 2>err &&
+	test_must_be_empty err
+'
+
 test_done