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>

5 files changed, 19 insertions, 30 deletions

diff --git a/t/README b/t/README
index 979b2d4833..29576c3748 100644
--- a/t/README
+++ b/t/README
@@ -449,10 +449,6 @@ the --sparse command-line argument.
 GIT_TEST_PRELOAD_INDEX=<boolean> exercises the preload-index code path
 by overriding the minimum number of cache entries required per thread.
 
-GIT_TEST_ADD_I_USE_BUILTIN=<boolean>, when false, disables the
-built-in version of git add -i. See 'add.interactive.useBuiltin' in
-git-config(1).
-
 GIT_TEST_INDEX_THREADS=<n> enables exercising the multi-threaded loading
 of the index for the whole test suite by bypassing the default number of
 cache entries and thread minimums. Setting this to 1 will make the
diff --git a/t/t2016-checkout-patch.sh b/t/t2016-checkout-patch.sh
index a5822e41af..747eb5563e 100755
--- a/t/t2016-checkout-patch.sh
+++ b/t/t2016-checkout-patch.sh
@@ -4,12 +4,6 @@ test_description='git checkout --patch'
 
 . ./lib-patch-mode.sh
 
-if ! test_have_prereq ADD_I_USE_BUILTIN && ! test_have_prereq PERL
-then
-	skip_all='skipping interactive add tests, PERL not set'
-	test_done
-fi
-
 test_expect_success 'setup' '
 	mkdir dir &&
 	echo parent > dir/foo &&
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 &&
diff --git a/t/t6132-pathspec-exclude.sh b/t/t6132-pathspec-exclude.sh
index cada952f9a..9fdafeb1e9 100755
--- a/t/t6132-pathspec-exclude.sh
+++ b/t/t6132-pathspec-exclude.sh
@@ -293,11 +293,7 @@ test_expect_success 'add with all negative' '
 	test_cmp expect actual
 '
 
-test_lazy_prereq ADD_I_USE_BUILTIN_OR_PERL '
-	test_have_prereq ADD_I_USE_BUILTIN || test_have_prereq PERL
-'
-
-test_expect_success ADD_I_USE_BUILTIN_OR_PERL 'add -p with all negative' '
+test_expect_success 'add -p with all negative' '
 	H=$(git rev-parse HEAD) &&
 	git reset --hard $H &&
 	git clean -f &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 01e88781dd..d272cca008 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1937,10 +1937,6 @@ test_lazy_prereq SHA1 '
 	esac
 '
 
-test_lazy_prereq ADD_I_USE_BUILTIN '
-	test_bool_env GIT_TEST_ADD_I_USE_BUILTIN true
-'
-
 # Ensure that no test accidentally triggers a Git command
 # that runs the actual maintenance scheduler, affecting a user's
 # system permanently.