From 80f05953111ee750e652c30d40b5c64e6d6815dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Mon, 5 May 2025 10:11:28 +0200
Subject: [PATCH] tpl: Fix case issue in templates.Exists

Fixes #13684
---
 tpl/templates/templates_integration_test.go | 16 ++++++++++++++++
 tpl/tplimpl/templatestore.go                |  1 +
 2 files changed, 17 insertions(+)

diff --git a/tpl/templates/templates_integration_test.go b/tpl/templates/templates_integration_test.go
index d16333ed4..baa917eee 100644
--- a/tpl/templates/templates_integration_test.go
+++ b/tpl/templates/templates_integration_test.go
@@ -299,3 +299,19 @@ P2.
 	b := hugolib.Test(t, files)
 	b.AssertFileContent("public/index.html", "P1: P1.\nP2: foo bar")
 }
+
+func TestTemplateExistsCaseIssue13684(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+-- layouts/home.html --
+P1: {{ templates.Exists "_partials/MyPartial.html" }}|P1: {{ templates.Exists "_partials/mypartial.html" }}|
+-- layouts/_partials/MyPartial.html --
+MyPartial.
+
+`
+
+	b := hugolib.Test(t, files)
+	b.AssertFileContent("public/index.html", "P1: true|P1: true|")
+}
diff --git a/tpl/tplimpl/templatestore.go b/tpl/tplimpl/templatestore.go
index 4adf76b29..53880eb33 100644
--- a/tpl/tplimpl/templatestore.go
+++ b/tpl/tplimpl/templatestore.go
@@ -712,6 +712,7 @@ func (s *TemplateStore) RefreshFiles(include func(fi hugofs.FileMetaInfo) bool)
 }
 
 func (s *TemplateStore) HasTemplate(templatePath string) bool {
+	templatePath = strings.ToLower(templatePath)
 	templatePath = paths.AddLeadingSlash(templatePath)
 	return s.templatesByPath.Contains(templatePath)
 }