content adapter: Fix issue with content starting out with a shortcode

Fixes #12544

2 files changed, 35 insertions, 8 deletions

diff --git a/hugolib/page__content.go b/hugolib/page__content.go
index 1ef31f0f9..1119a8a95 100644
--- a/hugolib/page__content.go
+++ b/hugolib/page__content.go
@@ -57,14 +57,14 @@ type pageContentReplacement struct {
 
 func (m *pageMeta) parseFrontMatter(h *HugoSites, pid uint64) (*contentParseInfo, error) {
 	var (
-		sourceKey  string
-		openSource hugio.OpenReadSeekCloser
-		hasContent = m.pageConfig.IsFromContentAdapter
+		sourceKey            string
+		openSource           hugio.OpenReadSeekCloser
+		isFromContentAdapter = m.pageConfig.IsFromContentAdapter
 	)
 
-	if m.f != nil && !hasContent {
+	if m.f != nil && !isFromContentAdapter {
 		sourceKey = filepath.ToSlash(m.f.Filename())
-		if !hasContent {
+		if !isFromContentAdapter {
 			meta := m.f.FileInfo().Meta()
 			openSource = func() (hugio.ReadSeekCloser, error) {
 				r, err := meta.Open()
@@ -74,7 +74,7 @@ func (m *pageMeta) parseFrontMatter(h *HugoSites, pid uint64) (*contentParseInfo
 				return r, nil
 			}
 		}
-	} else if hasContent {
+	} else if isFromContentAdapter {
 		openSource = m.pageConfig.Content.ValueAsOpenReadSeekCloser()
 	}
 
@@ -96,7 +96,9 @@ func (m *pageMeta) parseFrontMatter(h *HugoSites, pid uint64) (*contentParseInfo
 
 	items, err := pageparser.ParseBytes(
 		source,
-		pageparser.Config{},
+		pageparser.Config{
+			NoFrontMatter: isFromContentAdapter,
+		},
 	)
 	if err != nil {
 		return nil, err
@@ -104,7 +106,7 @@ func (m *pageMeta) parseFrontMatter(h *HugoSites, pid uint64) (*contentParseInfo
 
 	pi.itemsStep1 = items
 
-	if hasContent {
+	if isFromContentAdapter {
 		// No front matter.
 		return pi, nil
 	}
diff --git a/hugolib/pagesfromdata/pagesfromgotmpl_integration_test.go b/hugolib/pagesfromdata/pagesfromgotmpl_integration_test.go
index 7f0f19f1c..c7e3d96c7 100644
--- a/hugolib/pagesfromdata/pagesfromgotmpl_integration_test.go
+++ b/hugolib/pagesfromdata/pagesfromgotmpl_integration_test.go
@@ -585,3 +585,28 @@ value: data1
 
 	b.AssertLogNotContains("WARN")
 }
+
+func TestPagesFromGoTmplShortcodeNoPreceddingCharacterIssue12544(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ['home','rss','section','sitemap','taxonomy','term']
+-- content/_content.gotmpl --
+{{ $content := dict "mediaType" "text/html" "value" "x{{< sc >}}" }}
+{{ .AddPage (dict "content" $content "path" "a") }}
+
+{{ $content := dict "mediaType" "text/html" "value" "{{< sc >}}" }}
+{{ .AddPage (dict "content" $content "path" "b") }}
+-- layouts/_default/single.html --
+|{{ .Content }}|
+-- layouts/shortcodes/sc.html --
+foo
+{{- /**/ -}}
+`
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/a/index.html", "|xfoo|")
+	b.AssertFileContent("public/b/index.html", "|foo|") // fails
+}