From 888d5de655466a82090458fe100392c873533d7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Manuel=20R=C3=BCger?= <manuel@rueg.eu>
Date: Fri, 28 Nov 2025 14:33:32 +0100
Subject: [PATCH] fix: Panic on empty link

---
 renderer/link.go    | 2 +-
 testdata/links.html | 2 ++
 testdata/links.md   | 3 +++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/renderer/link.go b/renderer/link.go
index 7f26910..d387a61 100644
--- a/renderer/link.go
+++ b/renderer/link.go
@@ -26,7 +26,7 @@ func (r *ConfluenceLinkRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegi
 // renderLink renders links specifically for confluence
 func (r *ConfluenceLinkRenderer) renderLink(writer util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Link)
-	if string(n.Destination[0:3]) == "ac:" {
+	if len(n.Destination) >= 3 && string(n.Destination[0:3]) == "ac:" {
 		if entering {
 			_, err := writer.Write([]byte("<ac:link><ri:page ri:content-title=\""))
 			if err != nil {
diff --git a/testdata/links.html b/testdata/links.html
index d9ca603..6917b95 100644
--- a/testdata/links.html
+++ b/testdata/links.html
@@ -11,6 +11,8 @@
 <p><ac:link><ri:page ri:content-title="test_link_link"/><ac:plain-text-link-body><![CDATA[Another [Link]]]></ac:plain-text-link-body></ac:link></p>
 <p>Use footnotes link <sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup></p>
 <p>Use <a href="foo">Link [Text]</a></p>
+<h2 id="Empty-link">Empty link</h2>
+<p><a href=""></a></p>
 <div class="footnotes" role="doc-endnotes">
 <hr />
 <ol>
diff --git a/testdata/links.md b/testdata/links.md
index 073db52..48ce998 100644
--- a/testdata/links.md
+++ b/testdata/links.md
@@ -24,3 +24,6 @@ Use footnotes link [^1]
 [^1]: a footnote link
 
 Use [Link [Text]](foo)
+
+## Empty link
+[]()