From 63b2003520134dd3bc90ade3ad0c78d96461cff6 Mon Sep 17 00:00:00 2001
From: Kunal Mehta <legoktm@member.fsf.org>
Date: Fri, 17 Aug 2018 17:09:26 -0700
Subject: [PATCH] TitleFormatter: Implement fbc144965315 and unify prefix logic

fbc144965315 (Make Titles with an unknown namespace ID refer to
Special:Badtitle.) was never implemented in TitleFormatter, so let's do
that.

While we're at it, formatTitle() is now structured in the same format as
Title::prefix(), to make it easier to compare code between the two
implementations. The existing tests verify that this is a no-op. There's
a little extra indirection in getPrefixedDBkey(), which now goes through
dbkeyform -> textform -> dbkeyform, but reduces duplication of code,
which I think is worth it.

Bug: T165149
Change-Id: I4e43487a52663d2a647f9e71d487f58e25474f7a
---
 includes/title/MediaWikiTitleCodec.php        | 57 +++++++------------
 .../title/MediaWikiTitleCodecTest.php         |  4 +-
 2 files changed, 23 insertions(+), 38 deletions(-)

diff --git a/includes/title/MediaWikiTitleCodec.php b/includes/title/MediaWikiTitleCodec.php
index 15f8ff0997..3c14317e0b 100644
--- a/includes/title/MediaWikiTitleCodec.php
+++ b/includes/title/MediaWikiTitleCodec.php
@@ -79,7 +79,7 @@ class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
 	 * @param string $text
 	 *
 	 * @throws InvalidArgumentException If the namespace is invalid
-	 * @return string
+	 * @return string Namespace name with underscores (not spaces)
 	 */
 	public function getNamespaceName( $namespace, $text ) {
 		if ( $this->language->needsGenderDistinction() &&
@@ -112,29 +112,30 @@ class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
 	 * @return string
 	 */
 	public function formatTitle( $namespace, $text, $fragment = '', $interwiki = '' ) {
-		if ( $namespace !== 0 && $namespace !== false ) {
-			// Try to get a namespace name, but fallback
-			// to empty string if it doesn't exist. And
-			// assume that ns 0 is the empty string.
+		$out = '';
+		if ( $interwiki !== '' ) {
+			$out = $interwiki . ':';
+		}
+
+		if ( $namespace != 0 ) {
 			try {
 				$nsName = $this->getNamespaceName( $namespace, $text );
 			} catch ( InvalidArgumentException $e ) {
-				$nsName = '';
+				// See T165149. Awkward, but better than erroneously linking to the main namespace.
+				$nsName = $this->language->getNsText( NS_SPECIAL ) . ":Badtitle/NS{$namespace}";
 			}
-			$text = $nsName . ':' . $text;
-		}
 
-		if ( $fragment !== '' ) {
-			$text = $text . '#' . $fragment;
+			$out .= $nsName . ':';
 		}
+		$out .= $text;
 
-		if ( $interwiki !== '' ) {
-			$text = $interwiki . ':' . $text;
+		if ( $fragment !== '' ) {
+			$out .= '#' . $fragment;
 		}
 
-		$text = str_replace( '_', ' ', $text );
+		$out = str_replace( '_', ' ', $out );
 
-		return $text;
+		return $out;
 	}
 
 	/**
@@ -200,28 +201,12 @@ class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
 	 * @return string
 	 */
 	public function getPrefixedDBkey( LinkTarget $target ) {
-		$key = '';
-		if ( $target->isExternal() ) {
-			$key .= $target->getInterwiki() . ':';
-		}
-		// Try to get a namespace name, but fallback
-		// to empty string if it doesn't exist
-		try {
-			$nsName = $this->getNamespaceName(
-				$target->getNamespace(),
-				$target->getText()
-			);
-		} catch ( InvalidArgumentException $e ) {
-			$nsName = '';
-		}
-
-		if ( $target->getNamespace() !== 0 ) {
-			$key .= $nsName . ':';
-		}
-
-		$key .= $target->getText();
-
-		return strtr( $key, ' ', '_' );
+		return strtr( $this->formatTitle(
+			$target->getNamespace(),
+			$target->getDBkey(),
+			'',
+			$target->getInterwiki()
+		), ' ', '_' );
 	}
 
 	/**
diff --git a/tests/phpunit/includes/title/MediaWikiTitleCodecTest.php b/tests/phpunit/includes/title/MediaWikiTitleCodecTest.php
index e1b98ec341..20f0039f57 100644
--- a/tests/phpunit/includes/title/MediaWikiTitleCodecTest.php
+++ b/tests/phpunit/includes/title/MediaWikiTitleCodecTest.php
@@ -164,7 +164,7 @@ class MediaWikiTitleCodecTest extends MediaWikiTestCase {
 			// getGenderCache() provides a mock that considers first
 			// names ending in "a" to be female.
 			[ NS_USER, 'Lisa_Müller', '', 'de', 'Benutzerin:Lisa Müller' ],
-			[ 1000000, 'Invalid_namespace', '', 'en', ':Invalid namespace' ],
+			[ 1000000, 'Invalid_namespace', '', 'en', 'Special:Badtitle/NS1000000:Invalid namespace' ],
 		];
 	}
 
@@ -195,7 +195,7 @@ class MediaWikiTitleCodecTest extends MediaWikiTestCase {
 			[ NS_MAIN, 'Remote_page', '', 'remotetestiw', 'en', 'remotetestiw:Remote_page' ],
 
 			// non-existent namespace
-			[ 10000000, 'Foobar', '', '', 'en', ':Foobar' ],
+			[ 10000000, 'Foobar', '', '', 'en', 'Special:Badtitle/NS10000000:Foobar' ],
 		];
 	}
 
-- 
2.20.1