Merge branch 'PHP-7.4'

* PHP-7.4:
  Fix #77569: Write Acess Violation in DomImplementation

Author: cmb69

ext/dom/document.c

@@ -194,7 +194,7 @@ int dom_document_encoding_write(dom_object *obj, zval *newval)
 		return FAILURE;
 	}
 
-	handler = xmlFindCharEncodingHandler(Z_STRVAL_P(newval));
+	handler = xmlFindCharEncodingHandler(ZSTR_VAL(str));
 
     if (handler != NULL) {
 		xmlCharEncCloseFunc(handler);

ext/dom/tests/bug77569.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Bug #77569 (Write Acess Violation in DomImplementation)
+--SKIPIF--
+<?php
+if (!extension_loaded('dom')) die('skip dom extension not available');
+?>
+--FILE--
+<?php
+$imp = new DOMImplementation;
+$dom = $imp->createDocument("", "");
+$dom->encoding = null;
+?>
+--EXPECTF--
+Warning: main(): Invalid Document Encoding in %s on line %d