add: skip tracked paths outside sparse-checkout cone

When 'git add' adds a tracked file that is outside of the
sparse-checkout cone, it checks the SKIP_WORKTREE bit to see if the file
exists outside of the sparse-checkout cone. This is usually correct,
except in the case of a merge conflict outside of the cone.

Modify add_pathspec_matched_against_index() to be more careful about
paths by checking the sparse-checkout patterns in addition to the
SKIP_WORKTREE bit. This causes 'git add' to no longer allow files
outside of the cone that removed the SKIP_WORKTREE bit due to a merge
conflict.

With only this change, users will only be able to add the file after
adding the file to the sparse-checkout cone. A later change will allow
users to force adding even though the file is outside of the
sparse-checkout cone.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -94,6 +94,10 @@ static void update_callback(struct diff_queue_struct *q,
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
 		const char *path = p->one->path;
+
+		if (!path_in_sparse_checkout(path, &the_index))
+			continue;
+
 		switch (fix_unmerged_status(p, data)) {
 		default:
 			die(_("unexpected diff status %c"), p->status);

pathspec.c

@@ -39,7 +39,8 @@ void add_pathspec_matches_against_index(const struct pathspec *pathspec,
 		return;
 	for (i = 0; i < istate->cache_nr; i++) {
 		const struct cache_entry *ce = istate->cache[i];
-		if (sw_action == PS_IGNORE_SKIP_WORKTREE && ce_skip_worktree(ce))
+		if (sw_action == PS_IGNORE_SKIP_WORKTREE &&
+		    (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate)))
 			continue;
 		ce_path_match(istate, ce, pathspec, seen);
 	}
@@ -70,7 +71,7 @@ char *find_pathspecs_matching_skip_worktree(const struct pathspec *pathspec)
 
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce = istate->cache[i];
-		if (ce_skip_worktree(ce))
+		if (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate))
 		    ce_path_match(istate, ce, pathspec, seen);
 	}
 

t/t1091-sparse-checkout-builtin.sh

@@ -406,7 +406,7 @@ test_expect_success 'sparse-checkout (init|set|disable) warns with unmerged stat
 	git -C unmerged sparse-checkout disable
 '
 
-test_expect_success 'sparse-checkout reapply' '
+test_expect_failure 'sparse-checkout reapply' '
 	git clone repo tweak &&
 
 	echo dirty >tweak/deep/deeper2/a &&
@@ -438,6 +438,8 @@ test_expect_success 'sparse-checkout reapply' '
 	test_i18ngrep "warning.*The following paths are unmerged" err &&
 	test_path_is_file tweak/folder1/a &&
 
+	# NEEDSWORK: We are asking to update a file outside of the
+	# sparse-checkout cone, but this is no longer allowed.
 	git -C tweak add folder1/a &&
 	git -C tweak sparse-checkout reapply 2>err &&
 	test_must_be_empty err &&

t/t1092-sparse-checkout-compatibility.sh

@@ -546,10 +546,9 @@ test_expect_failure 'merge with conflict outside cone' '
 	test_all_match git status --porcelain=v2 &&
 
 	# 2. Add the file with conflict markers
-	# NEEDSWORK: Even though the merge conflict removed the
-	# SKIP_WORKTREE bit from the index entry for folder1/a, we should
-	# warn that this is a problematic add.
-	test_all_match git add folder1/a &&
+	test_sparse_match test_must_fail git add folder1/a &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/a &&
 	test_all_match git status --porcelain=v2 &&
 
 	# 3. Rename the file to another sparse filename and
@@ -558,7 +557,9 @@ test_expect_failure 'merge with conflict outside cone' '
 	# NEEDSWORK: This mode now fails, because folder2/z is
 	# outside of the sparse-checkout cone and does not match an
 	# existing index entry with the SKIP_WORKTREE bit cleared.
-	test_all_match git add folder2 &&
+	test_sparse_match test_must_fail git add folder2 &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder2/z &&
 	test_all_match git status --porcelain=v2 &&
 
 	test_all_match git merge --continue &&
@@ -586,7 +587,9 @@ test_expect_failure 'cherry-pick/rebase with conflict outside cone' '
 		# NEEDSWORK: Even though the merge conflict removed the
 		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
 		# warn that this is a problematic add.
-		test_all_match git add folder1/a &&
+		test_sparse_match test_must_fail git add folder1/a &&
+		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_sparse_unstaged folder1/a &&
 		test_all_match git status --porcelain=v2 &&
 
 		# 3. Rename the file to another sparse filename and
@@ -595,7 +598,9 @@ test_expect_failure 'cherry-pick/rebase with conflict outside cone' '
 		# outside of the sparse-checkout cone and does not match an
 		# existing index entry with the SKIP_WORKTREE bit cleared.
 		run_on_all mv folder2/a folder2/z &&
-		test_all_match git add folder2 &&
+		test_sparse_match test_must_fail git add folder2 &&
+		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_sparse_unstaged folder2/z &&
 		test_all_match git status --porcelain=v2 &&
 
 		test_all_match git $OPERATION --continue &&

t/t3705-add-sparse-checkout.sh

@@ -158,6 +158,18 @@ test_expect_success 'do not warn when pathspec matches dense entries' '
 	git ls-files --error-unmatch dense_entry
 '
 
+test_expect_success 'git add fails outside of sparse-checkout definition' '
+	test_when_finished git sparse-checkout disable &&
+	test_commit a &&
+	git sparse-checkout init &&
+	git sparse-checkout set a &&
+	echo >>sparse_entry &&
+
+	git update-index --no-skip-worktree sparse_entry &&
+	test_must_fail git add sparse_entry &&
+	test_sparse_entry_unstaged
+'
+
 test_expect_success 'add obeys advice.updateSparsePath' '
 	setup_sparse_entry &&
 	test_must_fail git -c advice.updateSparsePath=false add sparse_entry 2>stderr &&