Include name of page identity on failure within WikiPageFactory

Depend on PageReference::__toString for debug should be enough

Change-Id: I740c7ed0328eedaba4f66178ef7343833c87abe8

includes/page/PageAssertionException.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace MediaWiki\Page;
+
+use InvalidArgumentException;
+use Throwable;
+use Wikimedia\NormalizedException\INormalizedException;
+use Wikimedia\NormalizedException\NormalizedExceptionTrait;
+
+/**
+ * Exception if a PageIdentity is an invalid argument
+ *
+ * @newable
+ * @since 1.38
+ */
+class PageAssertionException extends InvalidArgumentException implements INormalizedException {
+
+	use NormalizedExceptionTrait;
+
+	/**
+	 * @stable to call
+	 * @param string $normalizedMessage The exception message, with PSR-3 style placeholders.
+	 * @param array $messageContext Message context, with values for the placeholders.
+	 * @param int $code The exception code.
+	 * @param Throwable|null $previous The previous throwable used for the exception chaining.
+	 */
+	public function __construct(
+		string $normalizedMessage = '',
+		array $messageContext = [],
+		int $code = 0,
+		Throwable $previous = null
+	) {
+		$this->normalizedMessage = $normalizedMessage;
+		$this->messageContext = $messageContext;
+		parent::__construct(
+			self::getMessageFromNormalizedMessage( $normalizedMessage, $messageContext ),
+			$code,
+			$previous
+		);
+	}
+}

includes/page/WikiPageFactory.php

@@ -3,7 +3,6 @@
 namespace MediaWiki\Page;
 
 use DBAccessObjectUtils;
-use InvalidArgumentException;
 use MediaWiki\Linker\LinkTarget;
 use MediaWiki\Page\Hook\WikiPageFactoryHook;
 use stdClass;
@@ -57,8 +56,9 @@ class WikiPageFactory {
 
 		if ( !$pageIdentity->canExist() ) {
 			// BC with the Title class
-			throw new InvalidArgumentException(
+			throw new PageAssertionException(
-				"The given PageIdentity does not represent a proper page"
+				'The given PageIdentity {pageIdentity} does not represent a proper page',
+				[ 'pageIdentity' => $pageIdentity ]
 			);
 		}