Remove WeakMap entries whose key is only reachable through the entry value

Zend/tests/weakrefs/gh10043-001.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Self-referencing map entry GC - 001
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$map[$obj] = $obj;
+
+gc_collect_cycles();
+
+var_dump($map);
+
+$obj = null;
+gc_collect_cycles();
+
+var_dump($map);
+
+--EXPECTF--
+object(WeakMap)#%d (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+  }
+}
+object(WeakMap)#%d (0) {
+}

Zend/tests/weakrefs/gh10043-002.phpt

@@ -0,0 +1,44 @@
+--TEST--
+Self-referencing map entry GC - 002
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$map[$obj] = [$obj];
+
+gc_collect_cycles();
+
+var_dump($map);
+
+$obj = null;
+gc_collect_cycles();
+
+var_dump($map);
+
+--EXPECTF--
+object(WeakMap)#%d (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    array(1) {
+      [0]=>
+      object(Value)#%d (1) {
+        ["value"]=>
+        string(1) "a"
+      }
+    }
+  }
+}
+object(WeakMap)#1 (0) {
+}

Zend/tests/weakrefs/gh10043-003.phpt

@@ -0,0 +1,50 @@
+--TEST--
+Self-referencing map entry GC - 003
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$map[$obj] = [$obj, $map];
+$ref = WeakReference::create($map);
+
+gc_collect_cycles();
+
+var_dump($ref->get());
+
+gc_collect_cycles();
+
+// $obj is first in the root buffer
+$obj = null;
+$map = null;
+gc_collect_cycles();
+
+var_dump($ref->get());
+
+--EXPECTF--
+object(WeakMap)#%d (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    array(2) {
+      [0]=>
+      object(Value)#%d (1) {
+        ["value"]=>
+        string(1) "a"
+      }
+      [1]=>
+      *RECURSION*
+    }
+  }
+}
+NULL

Zend/tests/weakrefs/gh10043-004.phpt

@@ -0,0 +1,50 @@
+--TEST--
+Self-referencing map entry GC - 004
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$map[$obj] = [$map, $obj];
+$ref = WeakReference::create($map);
+
+gc_collect_cycles();
+
+var_dump($ref->get());
+
+gc_collect_cycles();
+
+// $map is first in the root buffer
+$map = null;
+$obj = null;
+gc_collect_cycles();
+
+var_dump($ref->get());
+
+--EXPECTF--
+object(WeakMap)#%d (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    array(2) {
+      [0]=>
+      *RECURSION*
+      [1]=>
+      object(Value)#%d (1) {
+        ["value"]=>
+        string(1) "a"
+      }
+    }
+  }
+}
+NULL

Zend/tests/weakrefs/gh10043-005.phpt

@@ -0,0 +1,49 @@
+--TEST--
+Self-referencing map entry GC - 005
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$value = [$obj];
+$map[$obj] = $value;
+$obj = null;
+
+gc_collect_cycles();
+
+var_dump($map);
+
+gc_collect_cycles();
+
+$value = null;
+
+gc_collect_cycles();
+
+var_dump($map);
+
+--EXPECTF--
+object(WeakMap)#%d (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#%d (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    array(1) {
+      [0]=>
+      object(Value)#%d (1) {
+        ["value"]=>
+        string(1) "a"
+      }
+    }
+  }
+}
+object(WeakMap)#1 (0) {
+}

Zend/tests/weakrefs/gh10043-006.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Self-referencing map entry GC - 006
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+$map = new WeakMap();
+$obj = new Value('a');
+$map[$obj] = $obj;
+
+gc_collect_cycles();
+
+$obj2 = $obj;
+$obj = null;
+$map2 = $map;
+$map = null;
+
+gc_collect_cycles();
+
+var_dump($map2);
+
+--EXPECT--
+object(WeakMap)#1 (1) {
+  [0]=>
+  array(2) {
+    ["key"]=>
+    object(Value)#2 (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+    ["value"]=>
+    object(Value)#2 (1) {
+      ["value"]=>
+      string(1) "a"
+    }
+  }
+}

Zend/tests/weakrefs/gh10043-007.phpt

@@ -0,0 +1,33 @@
+--TEST--
+Self-referencing map entry GC - 007
+--FILE--
+<?php
+
+class Canary extends stdClass
+{
+    public function __construct(public string $name)
+    {
+    }
+
+    function __destruct()
+    {
+        echo $this->name."\n";
+    }
+}
+
+$container = new Canary('container');
+$canary = new Canary('canary');
+$container->canary = $canary;
+
+$map = new \WeakMap();
+$map[$canary] = $container;
+
+echo 1;
+unset($container, $canary);
+gc_collect_cycles();
+echo 2;
+
+--EXPECT--
+1container
+canary
+2

Zend/tests/weakrefs/gh10043-008.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Self-referencing map entry GC - 008
+--FILE--
+<?php
+
+class Canary extends stdClass
+{
+    public function __construct(public string $name)
+    {
+    }
+
+    function __destruct()
+    {
+        echo $this->name."\n";
+    }
+}
+
+$canary = new Canary('canary');
+
+$map = new \WeakMap();
+$map[$canary] = $canary;
+
+echo 1;
+unset($canary);
+gc_collect_cycles();
+echo 2;
+
+--EXPECT--
+1canary
+2

Zend/tests/weakrefs/gh10043-009.phpt

@@ -0,0 +1,28 @@
+--TEST--
+Self-referencing map entry GC - 009
+--FILE--
+<?php
+
+class Value {
+    public function __construct(public readonly string $value) {
+    }
+}
+
+function possibleRoot($var) {
+}
+
+$map = new WeakMap();
+$obj = new stdClass();
+$map[$obj] = new Value('a');
+$map[$map] = $map;
+$ref = WeakReference::create($map);
+
+possibleRoot($obj);
+$map = null;
+
+gc_collect_cycles();
+
+var_dump($ref->get());
+?>
+--EXPECT--
+NULL