add: remove "add.interactive.useBuiltin" & Perl "git add--interactive"

Since [1] first released with Git v2.37.0 the built-in version of "add
-i" has been the default. That built-in implementation was added in
[2], first released with Git v2.25.0.

At this point enough time has passed to allow for finding any
remaining bugs in this new implementation, so let's remove the
fallback code.

As with similar migrations for "stash"[3] and "rebase"[4] we're
keeping a mention of "add.interactive.useBuiltin" in the
documentation, but adding a warning() to notify any outstanding users
that the built-in is now the default. As with [5] and [6] we should
follow-up in the future and eventually remove that warning.

1. 0527ccb1b55 (add -i: default to the built-in implementation,
   2021-11-30)
2. f83dff60a78 (Start to implement a built-in version of `git add
   --interactive`, 2019-11-13)
3. 8a2cd3f5123 (stash: remove the stash.useBuiltin setting,
   2020-03-03)
4. d03ebd411c6 (rebase: remove the rebase.useBuiltin setting,
   2019-03-18)
5. deeaf5ee077 (stash: remove documentation for `stash.useBuiltin`,
   2022-01-27)
6. 9bcde4d5314 (rebase: remove transitory rebase.useBuiltin setting &
   env, 2021-03-23)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 18 insertions, 11 deletions

diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 5841f280fb..3a99837d9b 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -7,7 +7,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-terminal.sh
 
-if test_have_prereq !ADD_I_USE_BUILTIN,!PERL
+if test_have_prereq !PERL
 then
 	skip_all='skipping add -i (scripted) tests, perl not available'
 	test_done
@@ -46,6 +46,21 @@ force_color () {
 	)
 }
 
+test_expect_success 'warn about add.interactive.useBuiltin' '
+	cat >expect <<-\EOF &&
+	warning: the add.interactive.useBuiltin setting has been removed!
+	See its entry in '\''git help config'\'' for details.
+	No changes.
+	EOF
+
+	for v in = =true =false
+	do
+		git -c "add.interactive.useBuiltin$v" add -p >out 2>actual &&
+		test_must_be_empty out &&
+		test_cmp expect actual || return 1
+	done
+'
+
 test_expect_success 'setup (initial)' '
 	echo content >file &&
 	git add file &&
@@ -547,15 +562,7 @@ test_expect_success 'split hunk "add -p (edit)"' '
 	! grep "^+15" actual
 '
 
-test_expect_success 'setup ADD_I_USE_BUILTIN check' '
-	result=success &&
-	if ! test_have_prereq ADD_I_USE_BUILTIN
-	then
-		result=failure
-	fi
-'
-
-test_expect_$result 'split hunk "add -p (no, yes, edit)"' '
+test_expect_success 'split hunk "add -p (no, yes, edit)"' '
 	test_write_lines 5 10 20 21 30 31 40 50 60 >test &&
 	git reset &&
 	# test sequence is s(plit), n(o), y(es), e(dit)
@@ -579,7 +586,7 @@ test_expect_success 'split hunk with incomplete line at end' '
 	test_must_fail git grep --cached before
 '
 
-test_expect_$result 'edit, adding lines to the first hunk' '
+test_expect_success 'edit, adding lines to the first hunk' '
 	test_write_lines 10 11 20 30 40 50 51 60 >test &&
 	git reset &&
 	tr _ " " >patch <<-EOF &&