Fix #79332: php_istreams are never freed

Releasing the `com_dotnet_istream_wrapper` in `istream_destructor()` is
pointless, since `istream_destructor()` is only called when the
resource is going to be released.  This recursion is not a real issue,
though, since the resource is never exposed to userland, and has at
most refcount 1, so due to well defined unsigned integer underflow, it
never is released twice.  However, returning early in this case causes
a memory leak which needs to be fixed.

Author: cmb69

NEWS

@@ -14,6 +14,7 @@ PHP                                                                        NEWS
   . Fixed bug #79248 (Traversing empty VT_ARRAY throws com_exception). (cmb)
   . Fixed bug #79299 (com_print_typeinfo prints duplicate variables). (Litiano
     Moura)
+  . Fixed bug #79332 (php_istreams are never freed). (cmb)
 
 - DOM:
   . Fixed bug #77569: (Write Access Violation in DomImplementation). (Nikita,

ext/com_dotnet/com_persist.c

@@ -248,13 +248,6 @@ static struct IStreamVtbl php_istream_vtbl = {
 
 static void istream_destructor(php_istream *stm)
 {
-	if (stm->res) {
-		zend_resource *res = stm->res;
-		stm->res = NULL;
-		zend_list_delete(res);
-		return;
-	}
-
 	if (stm->refcount > 0) {
 		CoDisconnectObject((IUnknown*)stm, 0);
 	}
@@ -268,7 +261,6 @@ static void istream_destructor(php_istream *stm)
 PHP_COM_DOTNET_API IStream *php_com_wrapper_export_stream(php_stream *stream)
 {
 	php_istream *stm = (php_istream*)CoTaskMemAlloc(sizeof(*stm));
-	zval *tmp;
 
 	if (stm == NULL)
 		return NULL;
@@ -280,8 +272,7 @@ PHP_COM_DOTNET_API IStream *php_com_wrapper_export_stream(php_stream *stream)
 	stm->stream = stream;
 
 	GC_ADDREF(stream->res);
-	tmp = zend_list_insert(stm, le_istream);
-	stm->res = Z_RES_P(tmp);
+	stm->res = zend_register_resource(stm, le_istream);
 
 	return (IStream*)stm;
 }

ext/com_dotnet/tests/bug79332.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Bug #79332 (php_istreams are never freed)
+--SKIPIF--
+<?php
+if (!extension_loaded('com_dotnet')) die('com_dotnet extension not available');
+?>
+--FILE--
+<?php
+$ph = new COMPersistHelper(null);
+try {
+    $ph->LoadFromStream(fopen(__FILE__, 'r'));
+} catch (com_exception $ex) {
+    // use hard-coded message to avoid localization issues
+    echo "A com_exception has been thrown\n";
+}
+?>
+--EXPECT--
+A com_exception has been thrown