From 2dd87a6ef58c8c886dd209076aa6661ffae89577 Mon Sep 17 00:00:00 2001
From: Josh Goebel <me@joshgoebel.com>
Date: Sun, 13 Jun 2021 20:06:57 -0400
Subject: [PATCH] fix(markdown) Images with empty alt or links with empty text
 (#3233)

---
 CHANGES.md                            | 1 +
 src/languages/markdown.js             | 6 +++++-
 test/markup/markdown/links.expect.txt | 4 ++++
 test/markup/markdown/links.txt        | 4 ++++
 4 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 test/markup/markdown/links.expect.txt
 create mode 100644 test/markup/markdown/links.txt

diff --git a/CHANGES.md b/CHANGES.md
index a3a3065e64..33e360ba9e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -2,6 +2,7 @@
 
 Grammars:
 
+- fix(markdown) Images with empty alt or links with empty text (#3233) [Josh Goebel][]
 - enh(powershell) added `pwsh` alias (#3236) [tebeco][]
 - fix(r) fix bug highlighting examples in doc comments [Konrad Rudolph][]
 - fix(python) identifiers starting with underscore not highlighted (#3221) [Antoine Lambert][]
diff --git a/src/languages/markdown.js b/src/languages/markdown.js
index 51bbe56f3f..a6072587a6 100644
--- a/src/languages/markdown.js
+++ b/src/languages/markdown.js
@@ -105,12 +105,16 @@ export default function(hljs) {
       },
       // whatever else, lower relevance (might not be a link at all)
       {
-        begin: /\[.+?\]\(.*?\)/,
+        begin: /\[.*?\]\(.*?\)/,
         relevance: 0
       }
     ],
     returnBegin: true,
     contains: [
+      {
+        // empty strings for alt or link text
+        match: /\[(?=\])/
+      },
       {
         className: 'string',
         relevance: 0,
diff --git a/test/markup/markdown/links.expect.txt b/test/markup/markdown/links.expect.txt
new file mode 100644
index 0000000000..6156d28198
--- /dev/null
+++ b/test/markup/markdown/links.expect.txt
@@ -0,0 +1,4 @@
+![](<span class="hljs-link">https://example.com</span>)
+[](<span class="hljs-link">https://example.com</span>)
+![<span class="hljs-string">alt</span>](<span class="hljs-link">https://example.com</span>)
+[<span class="hljs-string">text</span>](<span class="hljs-link">https://example.com</span>)
diff --git a/test/markup/markdown/links.txt b/test/markup/markdown/links.txt
new file mode 100644
index 0000000000..36f6c9bfa2
--- /dev/null
+++ b/test/markup/markdown/links.txt
@@ -0,0 +1,4 @@
+![](https://example.com)
+[](https://example.com)
+![alt](https://example.com)
+[text](https://example.com)