Fix memory leak(null coalescing operator with Spl hash)

The SEPARATE_ARG_IF_REF macro increased the refcount of the object passed as a
key.
However, when the key did not exist in the ArrayAccess implementation,
the code returned early without trying to decrement the refcount.

Add a test of `??` succeeding+failing on a SplObjectStorage instance.

1 files changed, 15 insertions, 0 deletions

diff --git a/ext/spl/tests/observer_010.phpt b/ext/spl/tests/observer_010.phpt
new file mode 100644
index 0000000000..5cedff8c7c
--- /dev/null
+++ b/ext/spl/tests/observer_010.phpt
@@ -0,0 +1,15 @@
+--TEST--
+SPL: SplObjectStorage null coalescing operator memory leak
+--FILE--
+<?php
+// In maintainer zts mode, this should no longer
+// detect memory leaks for the objects
+$a = new stdClass();
+$b = new stdClass();
+$map = new SplObjectStorage();
+$map[$a] = 'foo';
+var_dump($map[$b] ?? null);
+var_dump($map[$a] ?? null);
+--EXPECTF--
+NULL
+string(3) "foo"