From b9c9321f1016c59521c84af66832d806e32b8b4a Mon Sep 17 00:00:00 2001
From: Tomas Husak <husaktomas98@gmail.com>
Date: Wed, 11 Aug 2021 13:32:41 +0200
Subject: [PATCH] Fix + test

---
 src/Peachpie.Library/pcre.cs  | 3 ++-
 tests/pcre/preg_match_006.php | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 tests/pcre/preg_match_006.php

diff --git a/src/Peachpie.Library/pcre.cs b/src/Peachpie.Library/pcre.cs
index 18d26c721..f840bb65d 100644
--- a/src/Peachpie.Library/pcre.cs
+++ b/src/Peachpie.Library/pcre.cs
@@ -981,7 +981,8 @@ namespace Pchp.Library
             {
                 var g = groups[i];
                 var value = (g.Success || !unmatchedAsNull) ? g.Value : null;
-                var item = NewArrayItem(value, g.Index, offsetCapture);
+                int index = g.Success ? g.Index : -1;
+                var item = NewArrayItem(value, index, offsetCapture);
 
                 // All groups should be named.
                 if (g.IsNamedGroup)
diff --git a/tests/pcre/preg_match_006.php b/tests/pcre/preg_match_006.php
new file mode 100644
index 000000000..79d525164
--- /dev/null
+++ b/tests/pcre/preg_match_006.php
@@ -0,0 +1,8 @@
+<?php
+namespace pcre\preg_match_006;
+
+preg_match('/(?P<fooname>foo)?(bar)/', 'bar', $matches, PREG_OFFSET_CAPTURE);
+
+$is_fooname = isset( $matches['fooname'] ) && -1 !== $matches['fooname'][1];
+
+echo "is_fooname:" . ($is_fooname ? "true" : "false") . "\n"; //is_fooname:false
\ No newline at end of file