From eb63e0c9182f203c8e6789f9b31892a2f34a169d Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Thu, 15 Oct 2020 01:59:07 +0200
Subject: [PATCH] Fix preg_match_all stub (#4325)

* preg_match_all can return false

* Test for preg_match_all returning false

* Fix test

* Add @psalm-ignore-falsable-return
---
 stubs/CoreGenericFunctions.phpstub | 3 ++-
 tests/FunctionCallTest.php         | 9 +++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/stubs/CoreGenericFunctions.phpstub b/stubs/CoreGenericFunctions.phpstub
index b4bcaaff9b3..f37af3c13c1 100644
--- a/stubs/CoreGenericFunctions.phpstub
+++ b/stubs/CoreGenericFunctions.phpstub
@@ -760,7 +760,8 @@ function preg_replace_callback($search, $replace, $subject, int $limit = -1, &$c
  *              )
  *          )
  *        ) $matches
- * @return int
+ * @return int|false
+ * @psalm-ignore-falsable-return
  */
 function preg_match_all($pattern, $replace, &$matches = [], int $flags = 1, int $offset = 0) {}
 
diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
index 95e822e0899..b5c91acc75b 100644
--- a/tests/FunctionCallTest.php
+++ b/tests/FunctionCallTest.php
@@ -1341,6 +1341,15 @@ function foo(string $input): array {
                         return $matches[0];
                     }'
             ],
+            'pregMatchAllReturnsFalse' => [
+                '<?php
+                    /**
+                     * @return int|false
+                     */
+                    function badpattern() {
+                        return @preg_match_all("foo", "foo", $matches);
+                    }'
+            ],
             'strposAllowDictionary' => [
                 '<?php
                     function sayHello(string $format): void {