From 9c57af1351c26631fcca9213db8778b056f8600d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Sun, 27 Jul 2025 12:02:21 +0200
Subject: [PATCH] Fix regression with hyphenated codeblock templates, e.g.
 render-codeblock-go-html-template.html

Fixes #13864

Co-authored-by: Joe Mooring <joe.mooring@veriphor.com>
---
 tpl/tplimpl/templatestore.go                  | 15 +++--
 tpl/tplimpl/templatestore_integration_test.go | 55 +++++++++++++++++++
 2 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/tpl/tplimpl/templatestore.go b/tpl/tplimpl/templatestore.go
index 008b743c7..caf53c005 100644
--- a/tpl/tplimpl/templatestore.go
+++ b/tpl/tplimpl/templatestore.go
@@ -1762,15 +1762,18 @@ func (s *TemplateStore) toKeyCategoryAndDescriptor(p *paths.Path) (string, strin
 	if category == CategoryMarkup {
 		// We store all template nodes for a given directory on the same level.
 		k1 = strings.TrimSuffix(k1, "/_markup")
-		parts := strings.Split(d.LayoutFromTemplate, "-")
-		if len(parts) < 2 {
+		v, found := strings.CutPrefix(d.LayoutFromTemplate, "render-")
+		if !found {
 			return "", "", 0, TemplateDescriptor{}, fmt.Errorf("unrecognized render hook template")
 		}
-		// Either 2 or 3 parts, e.g. render-codeblock-go.
-		d.Variant1 = parts[1]
-		if len(parts) > 2 {
-			d.Variant2 = parts[2]
+		hyphenIdx := strings.Index(v, "-")
+
+		d.Variant1 = v
+		if hyphenIdx > 0 {
+			d.Variant1 = v[:hyphenIdx]
+			d.Variant2 = v[hyphenIdx+1:]
 		}
+
 		d.LayoutFromTemplate = "" // This allows using page layout as part of the key for lookups.
 	}
 
diff --git a/tpl/tplimpl/templatestore_integration_test.go b/tpl/tplimpl/templatestore_integration_test.go
index 9da959350..13c4d5af9 100644
--- a/tpl/tplimpl/templatestore_integration_test.go
+++ b/tpl/tplimpl/templatestore_integration_test.go
@@ -393,6 +393,61 @@ Link: [Foo](/foo)
 	}
 }
 
+func TestCodeblockIssue13864(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ['page','rss','section','sitemap','taxonomy','term']
+-- content/_index.md --
+---
+title: home
+---
+
+~~~
+LANG: none
+~~~
+
+~~~go
+LANG: go
+~~~
+
+~~~go-html-template
+LANG: go-html-template
+~~~
+
+~~~xy
+LANG: xy
+~~~
+
+~~~x-y
+LANG: x-y
+~~~
+-- layouts/home.html --
+{{ .Content }}
+-- layouts/_markup/render-codeblock.html --
+{{ .Inner }} LAYOUT: render-codeblock.html|
+-- layouts/_markup/render-codeblock-go.html --
+{{ .Inner }} LAYOUT: render-codeblock-go.html|
+-- layouts/_markup/render-codeblock-go-html-template.html --
+{{ .Inner }} LAYOUT: render-codeblock-go-html-template.html|
+-- layouts/_markup/render-codeblock-xy.html --
+{{ .Inner }} LAYOUT: render-codeblock-xy.html|
+-- layouts/_markup/render-codeblock-x-y.html.html --
+{{ .Inner }} LAYOUT: render-codeblock-x-y.html|
+`
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/index.html",
+		"LANG: none LAYOUT: render-codeblock.html|",                              // pass
+		"LANG: go LAYOUT: render-codeblock-go.html|",                             // fail: uses render-codeblock-go-html-template.html
+		"LANG: go-html-template LAYOUT: render-codeblock-go-html-template.html|", // fail: uses render-codeblock.html
+		"LANG: xy LAYOUT: render-codeblock-xy.html|",                             // pass
+		"LANG: x-y LAYOUT: render-codeblock-x-y.html|",                           // fail: uses render-codeblock.html
+	)
+}
+
 func TestRenderCodeblockSpecificity(t *testing.T) {
 	files := `
 -- hugo.toml --