From efab7dc1f49ef95f00560c30bca357dd445e7cb4 Mon Sep 17 00:00:00 2001
From: Derrick Stolee <stolee@gmail.com>
Date: Fri, 16 May 2025 14:55:29 +0000
Subject: reset: integrate sparse index with --patch

Similar to the previous change for 'git add -p', the reset builtin
checked for integration with the sparse index after possibly redirecting
its logic toward the interactive logic. This means that the builtin
would expand the sparse index to a full one upon read.

Move this check earlier within cmd_reset() to improve performance here.

Add tests to guarantee that we are not universally expanding the index.
Add behavior tests to check that we are doing the same operations as a
full index.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t1092-sparse-checkout-compatibility.sh | 42 ++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

(limited to 't')

diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index f47cf8fa7f..e11dfd872e 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -384,7 +384,7 @@ test_expect_success 'add, commit, checkout' '
 	test_all_match git checkout -
 '
 
-test_expect_success 'git add -p' '
+test_expect_success 'git add, checkout, and reset with -p' '
 	init_repos &&
 
 	write_script edit-contents <<-\EOF &&
@@ -398,7 +398,7 @@ test_expect_success 'git add -p' '
 	test_write_lines y n >in &&
 	run_on_all git add -p <in &&
 	test_all_match git status --porcelain=v2 &&
-	test_all_match git reset &&
+	test_all_match git reset -p <in &&
 
 	test_write_lines u 1 "" q >in &&
 	run_on_all git add -i <in &&
@@ -413,6 +413,12 @@ test_expect_success 'git add -p' '
 	test_sparse_match git reset &&
 	test_write_lines u 2 3 "" q >in &&
 	run_on_all git add -i <in &&
+	test_sparse_match git status --porcelain=v2 &&
+
+	run_on_all git add --sparse folder1 &&
+	run_on_all git commit -m "take changes" &&
+	test_write_lines y n y >in &&
+	test_sparse_match git checkout HEAD~1 --patch <in &&
 	test_sparse_match git status --porcelain=v2
 '
 
@@ -2460,6 +2466,38 @@ test_expect_success 'sparse-index is not expanded: git add -p' '
 	ensure_expanded add -i <in
 '
 
+test_expect_success 'sparse-index is not expanded: checkout -p, reset -p' '
+	init_repos &&
+
+	# Does not expand when edits are within sparse checkout.
+	echo "new content" >sparse-index/deep/a &&
+	echo "new content" >sparse-index/deep/deeper1/a &&
+	git -C sparse-index commit -a -m "inside-changes" &&
+
+	test_write_lines y y >in &&
+	ensure_not_expanded checkout HEAD~1 --patch <in &&
+
+	echo "new content" >sparse-index/deep/a &&
+	echo "new content" >sparse-index/deep/deeper1/a &&
+	git -C sparse-index add . &&
+	ensure_not_expanded reset --patch <in &&
+
+	# -p does expand when edits are outside sparse checkout.
+	mkdir -p sparse-index/folder1 &&
+	echo "new content" >sparse-index/folder1/a &&
+	git -C sparse-index add --sparse folder1 &&
+	git -C sparse-index sparse-checkout reapply &&
+	ensure_expanded reset --patch <in &&
+
+	# Fully reset the index.
+	mkdir -p sparse-index/folder1 &&
+	echo "new content" >sparse-index/folder1/a &&
+	git -C sparse-index add --sparse folder1 &&
+	git -C sparse-index commit -m "folder1 change" &&
+	git -C sparse-index sparse-checkout reapply &&
+	ensure_expanded checkout HEAD~1 --patch <in
+'
+
 test_expect_success 'advice.sparseIndexExpanded' '
 	init_repos &&
 
-- 
cgit v1.3