Index: Cite_body.php
===================================================================
--- Cite_body.php	(revision 102969)
+++ Cite_body.php	(working copy)
@@ -1123,12 +1123,21 @@
 		# We rely on the fact that PHP is okay with passing unused argu-
 		# ments to functions.  If $1 is not used in the message, wfMsg will
 		# just ignore the extra parameter.
-		return
-			$this->parse(
-				'<strong class="error">' .
-				wfMsgNoTrans( 'cite_error', wfMsgNoTrans( $key, $param ) ) .
-				'</strong>'
-			);
+		# Also, use separate parser from MessageCache to avoid issues when
+		# errors are produced from ParserBeforeTidy (bug #17865). Error
+		# messages also should not pollute the wgParser state.
+		$string = MessageCache::singleton()->parse(
+					wfMsgNoTrans( 'cite_error', wfMsgNoTrans( $key, $param ) )
+				, $this->mParser->mTitle
+				, true
+			)->getText();
+		# Emulate 'parseinline' in wfMsgExt
+		$m = array();
+		if( preg_match( '/^<p>(.*)\n?<\/p>\n?$/sU', $string, $m ) ) {
+			$string = $m[1];
+		}
+		return '<strong class="error">' . $string . '</strong>';
+
 	}
 
 	/**