[PATCH 06/23] Teach diff machinery to respect skip-worktree bit

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 diff-lib.c                       |    5 +++--
 diff.c                           |    2 +-
 t/t7011-skip-worktree-reading.sh |   23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/diff-lib.c b/diff-lib.c
index 22da66e..b0b379d 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -159,7 +159,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 				continue;
 		}
 
-		if (ce_uptodate(ce))
+		if (ce_uptodate(ce) || ce_skip_worktree(ce))
 			continue;
 
 		/* If CE_VALID is set, don't look at workdir for file removal */
@@ -339,7 +339,8 @@ static void do_oneway_diff(struct unpack_trees_options *o,
 	int match_missing, cached;
 
 	/* if the entry is not checked out, don't examine work tree */
-	cached = o->index_only || (idx && (idx->ce_flags & CE_VALID));
+	cached = o->index_only ||
+		(idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 	/*
 	 * Backward compatibility wart - "diff-index -m" does
 	 * not mean "do not ignore merges", but "match_missing".
diff --git a/diff.c b/diff.c
index cd35e0c..3970df4 100644
--- a/diff.c
+++ b/diff.c
@@ -1805,7 +1805,7 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
 	 * If ce is marked as "assume unchanged", there is no
 	 * guarantee that work tree matches what we are looking for.
 	 */
-	if (ce->ce_flags & CE_VALID)
+	if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
 		return 0;
 
 	/*
diff --git a/t/t7011-skip-worktree-reading.sh b/t/t7011-skip-worktree-reading.sh
index ede3ee1..5db93d0 100755
--- a/t/t7011-skip-worktree-reading.sh
+++ b/t/t7011-skip-worktree-reading.sh
@@ -111,4 +111,27 @@ test_expect_success 'ls-files --modified' '
 	test -z "$(git ls-files -m)"
 '
 
+echo ":000000 100644 $ZERO_SHA1 $NULL_SHA1 A	1" > expected
+test_expect_success 'diff-index does not examine skip-worktree absent entries' '
+	setup_absent &&
+	git diff-index HEAD -- 1 > result &&
+	test_cmp expected result
+'
+
+test_expect_success 'diff-index does not examine skip-worktree dirty entries' '
+	setup_dirty &&
+	git diff-index HEAD -- 1 > result &&
+	test_cmp expected result
+'
+
+test_expect_success 'diff-files does not examine skip-worktree absent entries' '
+	setup_absent &&
+	test -z "$(git diff-files -- one)"
+'
+
+test_expect_success 'diff-files does not examine skip-worktree dirty entries' '
+	setup_dirty &&
+	test -z "$(git diff-files -- one)"
+'
+
 test_done
-- 
1.6.5.2.216.g9c1ec