[PATCH v2 8/8] fsmonitor: test with sparse index

["Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>

During the effort to protect uses of the index to operate on a full
index, we did not modify fsmonitor.c. This is because it already works
effectively with only the change to index_name_stage_pos(). The only
thing left to do is to test that it works correctly.

These tests are added to demonstrate that the behavior is the same
across a full index and a sparse index, but also that file modifications
to a tracked directory outside of the sparse cone will trigger
ensure_full_index().

Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
 t/t7519-status-fsmonitor.sh | 48 +++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
index 45d025f96010..f70fe961902e 100755
--- a/t/t7519-status-fsmonitor.sh
+++ b/t/t7519-status-fsmonitor.sh
@@ -73,6 +73,7 @@ test_expect_success 'setup' '
 	expect*
 	actual*
 	marker*
+	trace2*
 	EOF
 '
 
@@ -383,4 +384,51 @@ test_expect_success 'status succeeds after staging/unstaging' '
 	)
 '
 
+# Usage:
+# check_sparse_index_behavior [!]
+# If "!" is supplied, then we verify that we do not call ensure_full_index
+# during a call to 'git status'. Otherwise, we verify that we _do_ call it.
+check_sparse_index_behavior () {
+	git status --porcelain=v2 >expect &&
+	git sparse-checkout init --cone --sparse-index &&
+	git sparse-checkout set dir1 dir2 &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
+		git status --porcelain=v2 >actual &&
+	test_region $1 index ensure_full_index trace2.txt &&
+	test_cmp expect actual &&
+	rm trace2.txt &&
+	git sparse-checkout disable
+}
+
+test_expect_success 'status succeeds with sparse index' '
+	git reset --hard &&
+
+	test_config core.fsmonitor "$TEST_DIRECTORY/t7519/fsmonitor-all" &&
+	check_sparse_index_behavior ! &&
+
+	write_script .git/hooks/fsmonitor-test<<-\EOF &&
+		printf "last_update_token\0"
+	EOF
+	git config core.fsmonitor .git/hooks/fsmonitor-test &&
+	check_sparse_index_behavior ! &&
+
+	write_script .git/hooks/fsmonitor-test<<-\EOF &&
+		printf "last_update_token\0"
+		printf "dir1/modified\0"
+	EOF
+	check_sparse_index_behavior ! &&
+
+	cp -r dir1 dir1a &&
+	git add dir1a &&
+	git commit -m "add dir1a" &&
+
+	# This one modifies outside the sparse-checkout definition
+	# and hence we expect to expand the sparse-index.
+	write_script .git/hooks/fsmonitor-test<<-\EOF &&
+		printf "last_update_token\0"
+		printf "dir1a/modified\0"
+	EOF
+	check_sparse_index_behavior
+'
+
 test_done
-- 
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