Title: be more robust when handling invalid titles

The postcondition in getRootTitle and getBaseTitle was failing when
dealing with an invalid title. This patch makes these methods just
return the title unchanged when it is invalid, since we cannot expect to
parse invalid titles successfully.

Bug: T290194
Change-Id: I14d644c42130504055e04cc59d8d7558c93e445d

1 files changed, 30 insertions, 8 deletions

diff --git a/includes/title/Title.php b/includes/title/Title.php
index 4a40a7bb1e9f..80165a8b52e6 100644
--- a/includes/title/Title.php
+++ b/includes/title/Title.php
@@ -1971,10 +1971,21 @@ class Title implements LinkTarget, PageIdentity {
 	 */
 	public function getRootTitle() {
 		$title = self::makeTitleSafe( $this->mNamespace, $this->getRootText() );
-		Assert::postcondition(
-			$title !== null,
-			'makeTitleSafe() should always return a Title for the text returned by getRootText().'
-		);
+
+		if ( !$title ) {
+			if ( !$this->isValid() ) {
+				// If the title wasn't valid in the first place, we can't expect
+				// to successfully parse it. T290194
+				return $this;
+			}
+
+			Assert::postcondition(
+				$title !== null,
+				'makeTitleSafe() should always return a Title for the text ' .
+					'returned by getRootText().'
+			);
+		}
+
 		return $title;
 	}
 
@@ -2021,10 +2032,21 @@ class Title implements LinkTarget, PageIdentity {
 	 */
 	public function getBaseTitle() {
 		$title = self::makeTitleSafe( $this->mNamespace, $this->getBaseText() );
-		Assert::postcondition(
-			$title !== null,
-			'makeTitleSafe() should always return a Title for the text returned by getBaseText().'
-		);
+
+		if ( !$title ) {
+			if ( !$this->isValid() ) {
+				// If the title wasn't valid in the first place, we can't expect
+				// to successfully parse it. T290194
+				return $this;
+			}
+
+			Assert::postcondition(
+				$title !== null,
+				'makeTitleSafe() should always return a Title for the text ' .
+					'returned by getBaseText().'
+			);
+		}
+
 		return $title;
 	}