Fix GH-9266: GC root buffer keeps growing when dtors are present

Do not reset cleared count on GC rerun.

Closes GH-9265.

NEWS

@@ -5,6 +5,8 @@ PHP                                                                        NEWS
 - Core:
   . Fixed --CGI-- support of run-tests.php. (cmb)
   . Fixed incorrect double to long casting in latest clang. (zeriyoshi)
+  . Fixed bug GH-9266 (GC root buffer keeps growing when dtors are present).
+    (Michael Olšavský)
 
 - Date:
   . Fixed bug GH-8730 (DateTime::diff miscalculation is same time zone of

Zend/tests/gc_045.phpt

@@ -0,0 +1,58 @@
+--TEST--
+GC 045: Total count persisted when GC is rerun due to destructor call
+--INI--
+zend.enable_gc=1
+--FILE--
+<?php
+class GlobalData
+{
+    public static Bar $bar;
+}
+
+class Value
+{
+    public function __destruct()
+    {
+        new Bar();
+    }
+}
+
+class Bar
+{
+    public function __construct()
+    {
+        GlobalData::$bar = $this;
+    }
+}
+
+class Foo
+{
+    public Foo $selfRef;
+    public Value $val;
+
+    public function __construct(Value $val)
+    {
+        $this->val = $val;
+        $this->selfRef = $this;
+    }
+}
+
+for ($j = 0; $j < 10; $j++) {
+    for ($i = 0; $i < 3000; $i++) {
+        new Foo(new Value());
+    }
+}
+
+var_dump(gc_status());
+?>
+--EXPECT--
+array(4) {
+  ["runs"]=>
+  int(10)
+  ["collected"]=>
+  int(25000)
+  ["threshold"]=>
+  int(10001)
+  ["roots"]=>
+  int(10000)
+}

Zend/zend_gc.c

@@ -1439,12 +1439,13 @@ static void zend_gc_root_tmpvars(void);
 
 ZEND_API int zend_gc_collect_cycles(void)
 {
-	int count = 0;
+	int total_count = 0;
 	bool should_rerun_gc = 0;
 	bool did_rerun_gc = 0;
 
 rerun_gc:
 	if (GC_G(num_roots)) {
+		int count;
 		gc_root_buffer *current, *last;
 		zend_refcounted *p;
 		uint32_t gc_flags = 0;
@@ -1622,6 +1623,7 @@ ZEND_API int zend_gc_collect_cycles(void)
 
 		GC_TRACE("Collection finished");
 		GC_G(collected) += count;
+		total_count += count;
 		GC_G(gc_active) = 0;
 	}
 
@@ -1638,7 +1640,7 @@ ZEND_API int zend_gc_collect_cycles(void)
 finish:
 	zend_get_gc_buffer_release();
 	zend_gc_root_tmpvars();
-	return count;
+	return total_count;
 }
 
 ZEND_API void zend_gc_get_status(zend_gc_status *status)