From: Brad Jorsch <bjorsch@wikimedia.org>
Date: Mon, 22 Sep 2014 16:49:28 +0000 (-0400)
Subject: Break accidental references in Parser::__clone
X-Git-Tag: 1.31.0-rc.0~13885^2
X-Git-Url: http://git.cyclocoop.org/url?a=commitdiff_plain;h=8eeb906f93e67c43122fe3de4548b3d05bc8962c;p=lhc%2Fweb%2Fwiklou.git

Break accidental references in Parser::__clone

If you have a reference *to* an object field (anywhere in the call
stack) when you clone the object, the field will be cloned as a
reference rather than as a value.

So we have to break those unexpected references in the cloned object
manually, which is easy enough by making a non-reference copy and then
rebinding the cloned object's reference to this copy.

Bug: 56226
Change-Id: I9c600e9c0845b4fde0366126ce3809d74e2240b4
---

diff --git a/includes/parser/Parser.php b/includes/parser/Parser.php
index 84bb224300..8bd96b531f 100644
--- a/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@ -258,6 +258,21 @@ class Parser {
 	 */
 	public function __clone() {
 		$this->mInParse = false;
+
+		// Bug 56226: When you create a reference "to" an object field, that
+		// makes the object field itself be a reference too (until the other
+		// reference goes out of scope). When cloning, any field that's a
+		// reference is copied as a reference in the new object. Both of these
+		// are defined PHP5 behaviors, as inconvenient as it is for us when old
+		// hooks from PHP4 days are passing fields by reference.
+		foreach ( array( 'mStripState', 'mVarCache' ) as $k ) {
+			// Make a non-reference copy of the field, then rebind the field to
+			// reference the new copy.
+			$tmp = $this->$k;
+			$this->$k =& $tmp;
+			unset( $tmp );
+		}
+
 		wfRunHooks( 'ParserCloned', array( $this ) );
 	}