From 359e77d7c9cb44b46cc712fbdd9cb97460ef3ff8 Mon Sep 17 00:00:00 2001
From: Brad Jorsch <bjorsch@wikimedia.org>
Date: Wed, 15 Apr 2015 13:44:28 -0400
Subject: [PATCH] Parser: Avoid producing <span></span> in the TOC

If someone renames a section but wants old targeted links to still work,
<span id="old-anchor"></span> is the usual solution. And sometimes
people put it inside the section header markup, like

 == <span id="old-anchor"></span>New name ==

since putting it before makes it be considered part of the previous section
while putting it after causes the browser to scroll the section header
off the screen.

But this has the unfortunate side effect that the TOC text for that
section will be "<span></span>New name". We should strip that useless
empty span.

Bug: T96153
Change-Id: I47a33ceb79d48f6d0c38fa3b3814a378feb5e31e
---
 includes/parser/Parser.php   |  6 ++++++
 tests/parser/parserTests.txt | 16 ++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/includes/parser/Parser.php b/includes/parser/Parser.php
index 1603fc699f..55066845b7 100644
--- a/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@ -4554,6 +4554,12 @@ class Parser {
 				array( '', '<$1>' ),
 				$safeHeadline
 			);
+
+			# Strip '<span></span>', which is the result from the above if
+			# <span id="foo"></span> is used to produce an additional anchor
+			# for a section.
+			$tocline = str_replace( '<span></span>', '', $tocline );
+
 			$tocline = trim( $tocline );
 
 			# For the anchor, strip out HTML-y stuff period
diff --git a/tests/parser/parserTests.txt b/tests/parser/parserTests.txt
index 18d9aa85e0..1670fe4cc5 100644
--- a/tests/parser/parserTests.txt
+++ b/tests/parser/parserTests.txt
@@ -13744,6 +13744,22 @@ TOC regression (T11764)
 
 !! end
 
+!! test
+TOC for heading containing <span id="..."></span> (T96153)
+!! wikitext
+__FORCETOC__
+==<span id="old-anchor"></span>New title==
+!! html
+<div id="toc" class="toc"><div id="toctitle"><h2>Contents</h2></div>
+<ul>
+<li class="toclevel-1 tocsection-1"><a href="#New_title"><span class="tocnumber">1</span> <span class="toctext">New title</span></a></li>
+</ul>
+</div>
+
+<h2><span class="mw-headline" id="New_title"><span id="old-anchor"></span>New title</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/index.php?title=Parser_test&amp;action=edit&amp;section=1" title="Edit section: New title">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
+
+!! end
+
 !! test
 TOC with wgMaxTocLevel=3 (bug 6204)
 !! options
-- 
2.20.1