From 5a93bb6effae8921e767501a66f76ffbc2fd05bc Mon Sep 17 00:00:00 2001
From: Hypolite Petovan <hypolite@mrpetovan.com>
Date: Sun, 12 Sep 2021 00:05:22 -0400
Subject: [PATCH 1/2] Prevent expandTags to be performed on existing links in
 Module\Api\Mastodon\Statuses

- We never need to expand tags inside of an already existing BBCode url tag
---
 src/Module/Api/Mastodon/Statuses.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Module/Api/Mastodon/Statuses.php b/src/Module/Api/Mastodon/Statuses.php
index 6ae076733..ed5abf199 100644
--- a/src/Module/Api/Mastodon/Statuses.php
+++ b/src/Module/Api/Mastodon/Statuses.php
@@ -63,7 +63,10 @@ class Statuses extends BaseApi
 		// The imput is defined as text. So we can use Markdown for some enhancements
 		$body = Markdown::toBBCode($request['status']);
 
-		$body = BBCode::expandTags($body);
+		// Avoids potential double expansion of existing links
+		$body = BBCode::performWithEscapedTags($body, ['url'], function ($body) {
+			return BBCode::expandTags($body);
+		});
 
 		$item = [];
 		$item['uid']        = $uid;

From 8e99b7f77516ecaab2680f314177005f2dc5a658 Mon Sep 17 00:00:00 2001
From: Hypolite Petovan <hypolite@mrpetovan.com>
Date: Sun, 12 Sep 2021 00:06:14 -0400
Subject: [PATCH 2/2] Refine BBCode::expandTags regular expression

- Now requires the tag to be preceded by either a non-word character or a start of a line
- Added corresponding tests
---
 src/Content/Text/BBCode.php           |  5 +++--
 tests/src/Content/Text/BBCodeTest.php | 28 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/Content/Text/BBCode.php b/src/Content/Text/BBCode.php
index 5a2b966dd..4d495a72b 100644
--- a/src/Content/Text/BBCode.php
+++ b/src/Content/Text/BBCode.php
@@ -2289,14 +2289,14 @@ class BBCode
 	}
 
 	/**
-	 * Expand tags to URLs
+	 * Expand tags to URLs, checks the tag is at the start of a line or preceded by a non-word character
 	 *
 	 * @param string $body
 	 * @return string body with expanded tags
 	 */
 	public static function expandTags(string $body)
 	{
-		return preg_replace_callback("/([!#@])([^\^ \x0D\x0A,;:?\']*[^\^ \x0D\x0A,;:?!\'.])/",
+		return preg_replace_callback("/(?<=\W|^)([!#@])([^\^ \x0D\x0A,;:?'\"]*[^\^ \x0D\x0A,;:?!'\".])/",
 			function ($match) {
 				switch ($match[1]) {
 					case '!':
@@ -2309,6 +2309,7 @@ class BBCode
 						}
 						break;
 					case '#':
+					default:
 						return $match[1] . '[url=' . 'https://' . DI::baseUrl() . '/search?tag=' . $match[2] . ']' . $match[2] . '[/url]';
 				}
 			}, $body);
diff --git a/tests/src/Content/Text/BBCodeTest.php b/tests/src/Content/Text/BBCodeTest.php
index 2fcf5a5fa..e2c4d9288 100644
--- a/tests/src/Content/Text/BBCodeTest.php
+++ b/tests/src/Content/Text/BBCodeTest.php
@@ -75,6 +75,7 @@ class BBCodeTest extends MockedTest
 		           ->andReturn($baseUrlMock);
 		$baseUrlMock->shouldReceive('getHostname')->withNoArgs()->andReturn('friendica.local');
 		$baseUrlMock->shouldReceive('getUrlPath')->withNoArgs()->andReturn('');
+		$baseUrlMock->shouldReceive('__toString')->withNoArgs()->andReturn('friendica.local');
 
 		$config = \HTMLPurifier_HTML5Config::createDefault();
 		$config->set('HTML.Doctype', 'HTML5');
@@ -339,4 +340,31 @@ class BBCodeTest extends MockedTest
 
 		self::assertEquals($expected, $actual);
 	}
+
+	public function dataExpandTags()
+	{
+		return [
+			'bug-10692-non-word' => [
+				'[url=https://github.com/friendica/friendica/blob/2021.09-rc/src/Util/Logger/StreamLogger.php#L160]https://github.com/friendica/friendica/blob/2021.09-rc/src/Util/Logger/StreamLogger.php#L160[/url]',
+				'[url=https://github.com/friendica/friendica/blob/2021.09-rc/src/Util/Logger/StreamLogger.php#L160]https://github.com/friendica/friendica/blob/2021.09-rc/src/Util/Logger/StreamLogger.php#L160[/url]',
+			],
+			'bug-10692-start-line' => [
+				'#[url=https://friendica.local/search?tag=L160]L160[/url]',
+				'#L160',
+			]
+		];
+	}
+
+	/**
+	 * @dataProvider dataExpandTags
+	 *
+	 * @param string $expected Expected BBCode output
+	 * @param string $text     Input text
+	 */
+	public function testExpandTags(string $expected, string $text)
+	{
+		$actual = BBCode::expandTags($text);
+
+		self::assertEquals($expected, $actual);
+	}
 }