Merge branch 'ds/sparse-checkout-malformed-pattern-fix'

Certain sparse-checkout patterns that are valid in non-cone mode
led to segfault in cone mode, which has been corrected.

* ds/sparse-checkout-malformed-pattern-fix:
  sparse-checkout: refuse to add to bad patterns
  sparse-checkout: fix OOM error with mixed patterns
  sparse-checkout: fix segfault on malformed patterns

builtin/sparse-checkout.c

@@ -504,7 +504,7 @@ static void insert_recursive_pattern(struct pattern_list *pl, struct strbuf *pat
 		char *oldpattern = e->pattern;
 		size_t newlen;
 
-		if (slash == e->pattern)
+		if (!slash || slash == e->pattern)
 			break;
 
 		newlen = slash - e->pattern;
@@ -612,6 +612,9 @@ static void add_patterns_cone_mode(int argc, const char **argv,
 		die(_("unable to load existing sparse-checkout patterns"));
 	free(sparse_filename);
 
+	if (!existing.use_cone_patterns)
+		die(_("existing sparse-checkout patterns do not use cone mode"));
+
 	hashmap_for_each_entry(&existing.recursive_hashmap, &iter, pe, ent) {
 		if (!hashmap_contains_parent(&pl->recursive_hashmap,
 					pe->pattern, &buffer) ||

dir.c

@@ -727,7 +727,7 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern
 	}
 
 	if (given->patternlen < 2 ||
-	    *given->pattern == '*' ||
+	    *given->pattern != '/' ||
 	    strstr(given->pattern, "**")) {
 		/* Not a cone pattern. */
 		warning(_("unrecognized pattern: '%s'"), given->pattern);
@@ -819,9 +819,7 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern
 		/* we already included this at the parent level */
 		warning(_("your sparse-checkout file may have issues: pattern '%s' is repeated"),
 			given->pattern);
-		hashmap_remove(&pl->parent_hashmap, &translated->ent, &data);
-		free(data);
-		free(translated);
+		goto clear_hashmaps;
 	}
 
 	return;

t/t1091-sparse-checkout-builtin.sh

@@ -111,6 +111,18 @@ test_expect_success 'clone --sparse' '
 	check_files clone a
 '
 
+test_expect_success 'switching to cone mode with non-cone mode patterns' '
+	git init bad-patterns &&
+	(
+		cd bad-patterns &&
+		git sparse-checkout init &&
+		git sparse-checkout add dir &&
+		git config core.sparseCheckoutCone true &&
+		test_must_fail git sparse-checkout add dir 2>err &&
+		grep "existing sparse-checkout patterns do not use cone mode" err
+	)
+'
+
 test_expect_success 'interaction with clone --no-checkout (unborn index)' '
 	git clone --no-checkout "file://$(pwd)/repo" clone_no_checkout &&
 	git -C clone_no_checkout sparse-checkout init --cone &&
@@ -173,12 +185,14 @@ test_expect_success 'set sparse-checkout using --stdin' '
 '
 
 test_expect_success 'add to sparse-checkout' '
-	cat repo/.git/info/sparse-checkout >expect &&
+	cat repo/.git/info/sparse-checkout >old &&
+	test_when_finished cp old repo/.git/info/sparse-checkout &&
 	cat >add <<-\EOF &&
 	pattern1
 	/folder1/
 	pattern2
 	EOF
+	cat old >expect &&
 	cat add >>expect &&
 	git -C repo sparse-checkout add --stdin <add &&
 	git -C repo sparse-checkout list >actual &&
@@ -716,4 +730,25 @@ test_expect_success 'cone mode clears ignored subdirectories' '
 	test_cmp expect out
 '
 
+test_expect_success 'malformed cone-mode patterns' '
+	git -C repo sparse-checkout init --cone &&
+	mkdir -p repo/foo/bar &&
+	touch repo/foo/bar/x repo/foo/y &&
+	cat >repo/.git/info/sparse-checkout <<-\EOF &&
+	/*
+	!/*/
+	/foo/
+	!/foo/*/
+	/foo/\*/
+	EOF
+
+	# Listing the patterns will notice the duplicate pattern and
+	# emit a warning. It will list the patterns directly instead
+	# of using the cone-mode translation to a set of directories.
+	git -C repo sparse-checkout list >actual 2>err &&
+	test_cmp repo/.git/info/sparse-checkout actual &&
+	grep "warning: your sparse-checkout file may have issues: pattern .* is repeated" err &&
+	grep "warning: disabling cone pattern matching" err
+'
+
 test_done