From 28a9df3159959ce66755c88787fefba221ce02e9 Mon Sep 17 00:00:00 2001
From: Cimbali <me@cimba.li>
Date: Tue, 13 Jun 2023 17:56:13 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=91=8C=20Improve=20default=20slug=20gener?=
 =?UTF-8?q?ation=20for=20heading=20anchors=20(#753)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This commit makes the slug generation closer to GitHub,
in that, starting/ending whitespace will not be stripped.

For example, ``#  ` a` b `c ` `` will now correctly create the slug
`-a-b-c-` and not `a-b-c`

Co-authored-by: Chris Sewell <chrisj_sewell@hotmail.com>
---
 myst_parser/mdit_to_docutils/base.py               |  2 +-
 tests/test_sphinx/sourcedirs/references/index.md   |  4 ++++
 .../test_sphinx_builds/test_references.html        | 14 ++++++++++++++
 .../test_references.resolved.xml                   |  9 ++++++++-
 .../test_sphinx_builds/test_references.xml         |  9 ++++++++-
 5 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/myst_parser/mdit_to_docutils/base.py b/myst_parser/mdit_to_docutils/base.py
index c70ae8fb..b70db12e 100644
--- a/myst_parser/mdit_to_docutils/base.py
+++ b/myst_parser/mdit_to_docutils/base.py
@@ -1974,7 +1974,7 @@ def default_slugify(title: str) -> str:
     - https://github.com/jch/html-pipeline/blob/master/lib/html/pipeline/toc_filter.rb
     - https://gist.github.com/asabaylus/3071099
     """
-    return _SLUGIFY_CLEAN_REGEX.sub("", title.strip().lower().replace(" ", "-"))
+    return _SLUGIFY_CLEAN_REGEX.sub("", title.lower().replace(" ", "-"))
 
 
 def compute_unique_slug(
diff --git a/tests/test_sphinx/sourcedirs/references/index.md b/tests/test_sphinx/sourcedirs/references/index.md
index 74d0fd6a..5255b475 100644
--- a/tests/test_sphinx/sourcedirs/references/index.md
+++ b/tests/test_sphinx/sourcedirs/references/index.md
@@ -67,3 +67,7 @@ Known explicit [**hallo**](#paragraph-target)
 Known with title [](#title-target)
 
 Ambiguous [](#duplicate)
+
+# Image in title ![badge](https://shields.io/or/something.svg)
+
+[link up](#image-in-title-)
diff --git a/tests/test_sphinx/test_sphinx_builds/test_references.html b/tests/test_sphinx/test_sphinx_builds/test_references.html
index 55b13a77..35d1aed7 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_references.html
+++ b/tests/test_sphinx/test_sphinx_builds/test_references.html
@@ -263,6 +263,20 @@ <h1>
      </a>
     </p>
    </section>
+   <section class="tex2jax_ignore mathjax_ignore" id="image-in-title">
+    <h1>
+     Image in title
+     <img alt="badge" src="https://shields.io/or/something.svg"/>
+     <a class="headerlink" href="#image-in-title" title="Permalink to this heading">
+      ¶
+     </a>
+    </h1>
+    <p>
+     <a class="reference internal" href="#image-in-title">
+      link up
+     </a>
+    </p>
+   </section>
   </div>
  </div>
 </div>
diff --git a/tests/test_sphinx/test_sphinx_builds/test_references.resolved.xml b/tests/test_sphinx/test_sphinx_builds/test_references.resolved.xml
index 58d73540..f832d049 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_references.resolved.xml
+++ b/tests/test_sphinx/test_sphinx_builds/test_references.resolved.xml
@@ -1,6 +1,6 @@
 <document source="index.md">
     <target refid="title">
-    <section classes="tex2jax_ignore mathjax_ignore" ids="title-with-nested-a-1 title" names="title\ with\ nested\ a=1 title" slug="title-with-nested">
+    <section classes="tex2jax_ignore mathjax_ignore" ids="title-with-nested-a-1 title" names="title\ with\ nested\ a=1 title" slug="title-with-nested-">
         <title>
             Title with 
             <strong>
@@ -150,3 +150,10 @@
             <reference internal="False" reftitle="Example 0.0.1" refuri="https://example.com/index.html#module-duplicate">
                 <literal classes="iref myst">
                     duplicate
+    <section classes="tex2jax_ignore mathjax_ignore" ids="image-in-title" names="image\ in\ title" slug="image-in-title-">
+        <title>
+            Image in title 
+            <image alt="badge" candidates="{'?': 'https://shields.io/or/something.svg'}" uri="https://shields.io/or/something.svg">
+        <paragraph>
+            <reference id_link="True" refid="image-in-title">
+                link up
diff --git a/tests/test_sphinx/test_sphinx_builds/test_references.xml b/tests/test_sphinx/test_sphinx_builds/test_references.xml
index 5069acec..4968ca2f 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_references.xml
+++ b/tests/test_sphinx/test_sphinx_builds/test_references.xml
@@ -1,6 +1,6 @@
 <document source="index.md">
     <target refid="title">
-    <section classes="tex2jax_ignore mathjax_ignore" ids="title-with-nested-a-1 title" names="title\ with\ nested\ a=1 title" slug="title-with-nested">
+    <section classes="tex2jax_ignore mathjax_ignore" ids="title-with-nested-a-1 title" names="title\ with\ nested\ a=1 title" slug="title-with-nested-">
         <title>
             Title with 
             <strong>
@@ -128,3 +128,10 @@
             Ambiguous 
             <pending_xref refdoc="index" refdomain="True" refexplicit="False" reftarget="duplicate" reftype="myst">
                 <inline classes="xref myst">
+    <section classes="tex2jax_ignore mathjax_ignore" ids="image-in-title" names="image\ in\ title" slug="image-in-title-">
+        <title>
+            Image in title 
+            <image alt="badge" candidates="{'?': 'https://shields.io/or/something.svg'}" uri="https://shields.io/or/something.svg">
+        <paragraph>
+            <reference id_link="True" refid="image-in-title">
+                link up