From b3574162737da627c76fcb9ddfb43918452b5519 Mon Sep 17 00:00:00 2001
From: Erik Bernhardson <ebernhardson@wikimedia.org>
Date: Mon, 10 Sep 2018 13:29:08 -0700
Subject: [PATCH] Go search to consider fragment only title invalid

When submiting using the 'go' feature of Special:Search (standard
usecase for autocomplete) a nearby title can be selected.
Unfortunately a fragment only title is considered valid, which
sends the user to Main_Page#searchterm.

Instead don't allow a search starting with # to trigger the go
feature.

Bug: T182452
Change-Id: I8ce3ce8633e23db41ae6eafb9996ca7294f8445a
---
 includes/search/SearchNearMatcher.php         |  8 ++++-
 .../includes/search/SearchNearMatcherTest.php | 30 +++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 tests/phpunit/includes/search/SearchNearMatcherTest.php

diff --git a/includes/search/SearchNearMatcher.php b/includes/search/SearchNearMatcher.php
index 27046f3156..0a644934c4 100644
--- a/includes/search/SearchNearMatcher.php
+++ b/includes/search/SearchNearMatcher.php
@@ -53,7 +53,6 @@ class SearchNearMatcher {
 	 */
 	protected function getNearMatchInternal( $searchterm ) {
 		$lang = $this->language;
-
 		$allSearchTerms = [ $searchterm ];
 
 		if ( $lang->hasVariants() ) {
@@ -68,6 +67,13 @@ class SearchNearMatcher {
 			return $titleResult;
 		}
 
+		// Most of our handling here deals with finding a valid title for the search term,
+		// but almost anything starting with '#' is "valid" and points to Main_Page#searchterm.
+		// Rather than doing something completely wrong, do nothing.
+		if ( $searchterm === '' || $searchterm[0] === '#' ) {
+			return null;
+		}
+
 		foreach ( $allSearchTerms as $term ) {
 			# Exact match? No need to look further.
 			$title = Title::newFromText( $term );
diff --git a/tests/phpunit/includes/search/SearchNearMatcherTest.php b/tests/phpunit/includes/search/SearchNearMatcherTest.php
new file mode 100644
index 0000000000..132011aab6
--- /dev/null
+++ b/tests/phpunit/includes/search/SearchNearMatcherTest.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * @covers SearchNearMatcher
+ */
+class SearchNearMatcherTest extends \PHPUnit\Framework\TestCase {
+	public function nearMatchProvider() {
+		return [
+			'empty request returns nothing' => [ null, 'en', '' ],
+			'default behaviour' => [ 'Near Match Test', 'en', 'near match test' ],
+			'with a hash returns nothing' => [ null, 'en', '#near match test' ],
+		];
+	}
+
+	/**
+	 * @dataProvider nearMatchProvider
+	 */
+	public function testNearMatch( $expected, $langCode, $searchterm ) {
+		$linkCache = MediaWiki\MediaWikiServices::getInstance()->getLinkCache();
+		$linkCache->addGoodLinkObj( 42, Title::newFromText( 'Near Match Test' ) );
+		$config = new HashConfig( [
+			'EnableSearchContributorsByIP' => false,
+		] );
+		$lang = Language::factory( $langCode );
+		$matcher = new SearchNearMatcher( $config, $lang );
+
+		$title = $matcher->getNearMatch( $searchterm );
+		$this->assertEquals( $expected, $title === null ? null : (string)$title );
+	}
+}
-- 
2.20.1