From 4597559d84635dd68e88dff274125d248a4bf5a2 Mon Sep 17 00:00:00 2001
From: Brad Jorsch <bjorsch@wikimedia.org>
Date: Sun, 27 Jan 2019 14:13:10 -0800
Subject: [PATCH] RemexCompatMunger: Don't split p-wrapping on style/link tags

<style> and <link> tags are metadata tags, they shouldn't split the <p>
tag when p-wrapping content.

Bug: T208901
Change-Id: I2ef5da68c9ccde4477d8295dfe4abf8497c5d26e
---
 includes/tidy/RemexCompatMunger.php           | 21 ++++++++++++++++++-
 .../phpunit/includes/tidy/RemexDriverTest.php | 20 ++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/includes/tidy/RemexCompatMunger.php b/includes/tidy/RemexCompatMunger.php
index 78a11045ed..df9bb96743 100644
--- a/includes/tidy/RemexCompatMunger.php
+++ b/includes/tidy/RemexCompatMunger.php
@@ -72,6 +72,21 @@ class RemexCompatMunger implements TreeHandler {
 		"mark" => true,
 	];
 
+	/**
+	 * For the purposes of this class, "metadata" elements are those that
+	 * should neither trigger p-wrapping nor stop an outer p-wrapping,
+	 * typically those that are themselves invisible in a browser's rendering.
+	 * This isn't a complete list, it's just the tags that we're likely to
+	 * encounter in practice.
+	 * @var array
+	 */
+	private static $metadataElements = [
+		'style' => true,
+		'script' => true,
+		'link' => true,
+		'meta' => true,
+	];
+
 	private static $formattingElements = [
 		'a' => true,
 		'b' => true,
@@ -261,7 +276,11 @@ class RemexCompatMunger implements TreeHandler {
 		$under = $preposition === TreeBuilder::UNDER;
 		$elementToEnd = null;
 
-		if ( $under && $parentData->isPWrapper && !$inline ) {
+		if ( isset( self::$metadataElements[$elementName] ) ) {
+			// The element is a metadata element, that we allow to appear in
+			// both inline and block contexts.
+			$this->trace( 'insert metadata' );
+		} elseif ( $under && $parentData->isPWrapper && !$inline ) {
 			// [B/b] The element is non-inline and the parent is a p-wrapper,
 			// close the parent and insert into its parent instead
 			$this->trace( 'insert B/b' );
diff --git a/tests/phpunit/includes/tidy/RemexDriverTest.php b/tests/phpunit/includes/tidy/RemexDriverTest.php
index a5ebaa5ddc..faa9aa1752 100644
--- a/tests/phpunit/includes/tidy/RemexDriverTest.php
+++ b/tests/phpunit/includes/tidy/RemexDriverTest.php
@@ -262,6 +262,26 @@ class RemexDriverTest extends MediaWikiTestCase {
 			'<i><blockquote><p></i>',
 			'<i></i><blockquote><p><i></i></p><p><i></i></p></blockquote>',
 		],
+		[
+			'style tag isn\'t p-wrapped (T186965)',
+			'<style>/* ... */</style>',
+			'<style>/* ... */</style>',
+		],
+		[
+			'link tag isn\'t p-wrapped (T186965)',
+			'<link rel="foo" href="bar" />',
+			'<link rel="foo" href="bar" />',
+		],
+		[
+			'style tag doesn\'t split p-wrapping (T208901)',
+			'foo <style>/* ... */</style> bar',
+			'<p>foo <style>/* ... */</style> bar</p>',
+		],
+		[
+			'link tag doesn\'t split p-wrapping (T208901)',
+			'foo <link rel="foo" href="bar" /> bar',
+			'<p>foo <link rel="foo" href="bar" /> bar</p>',
+		],
 	];
 
 	public function provider() {
-- 
2.20.1