Fix baseof with regular define regression

Fixes gohugoio#6790

hugolib/template_test.go

@@ -361,6 +361,43 @@ Base %d: {{ block "main" . }}FOO{{ end }}
 
 }
 
+// https://github.com/gohugoio/hugo/issues/6790
+func TestTemplateNoBasePlease(t *testing.T) {
+	t.Parallel()
+	b := newTestSitesBuilder(t).WithSimpleConfigFile()
+
+	b.WithTemplates("_default/list.html", `
+	{{ define "main" }}
+	  Bonjour
+	{{ end }}
+
+	{{ printf "list" }}
+
+
+	`)
+
+	b.WithTemplates(
+		"_default/single.html", `
+{{ printf "single" }}
+{{ define "main" }}
+  Bonjour
+{{ end }}
+
+
+`)
+
+	b.WithContent("blog/p1.md", `---
+title: The Page
+---
+`)
+
+	b.Build(BuildCfg{})
+
+	b.AssertFileContent("public/blog/p1/index.html", `single`)
+	b.AssertFileContent("public/blog/index.html", `list`)
+
+}
+
 func TestTemplateLookupSite(t *testing.T) {
 	t.Run("basic", func(t *testing.T) {
 		t.Parallel()

tpl/tplimpl/template.go

@@ -72,7 +72,9 @@ var (
 	_ tpl.Info     = (*templateState)(nil)
 )
 
-var defineRe = regexp.MustCompile(`{{-?\s?define`)
+// A template needing a base template is a template with only define sections,
+// but we check only for the start.
+var defineRe = regexp.MustCompile(`^\s*{{-?\s?define`)
 
 func newIdentity(name string) identity.Manager {
 	return identity.NewManager(identity.NewPathIdentity(files.ComponentFolderLayouts, name))
@@ -379,20 +381,19 @@ func (t *templateHandler) findLayout(d output.LayoutDescriptor, f output.Format)
 			}
 		}
 
-		if !found {
-			return nil, false, errors.Errorf("no baseof layout found for %q:", name)
-		}
-
 		templ, err := t.applyBaseTemplate(overlay, base)
 		if err != nil {
 			return nil, false, err
 		}
 
 		ts := newTemplateState(templ, overlay)
-		ts.baseInfo = base
 
-		// Add the base identity to detect changes
-		ts.Add(identity.NewPathIdentity(files.ComponentFolderLayouts, base.name))
+		if found {
+			ts.baseInfo = base
+
+			// Add the base identity to detect changes
+			ts.Add(identity.NewPathIdentity(files.ComponentFolderLayouts, base.name))
+		}
 
 		t.applyTemplateTransformers(t.main, ts)
 
@@ -565,20 +566,35 @@ func (t *templateHandler) addTemplateTo(info templateInfo, to *templateNamespace
 
 func (t *templateHandler) applyBaseTemplate(overlay, base templateInfo) (tpl.Template, error) {
 	if overlay.isText {
-		templ, err := t.main.prototypeTextClone.New(overlay.name).Parse(base.template)
-		if err != nil {
-			return nil, base.errWithFileContext("parse failed", err)
+		var (
+			templ = t.main.prototypeTextClone.New(overlay.name)
+			err   error
+		)
+
+		if !base.IsZero() {
+			templ, err = templ.Parse(base.template)
+			if err != nil {
+				return nil, base.errWithFileContext("parse failed", err)
+			}
 		}
+
 		templ, err = templ.Parse(overlay.template)
 		if err != nil {
 			return nil, overlay.errWithFileContext("parse failed", err)
 		}
 		return templ, nil
 	}
 
-	templ, err := t.main.prototypeHTMLClone.New(overlay.name).Parse(base.template)
-	if err != nil {
-		return nil, base.errWithFileContext("parse failed", err)
+	var (
+		templ = t.main.prototypeHTMLClone.New(overlay.name)
+		err   error
+	)
+
+	if !base.IsZero() {
+		templ, err = templ.Parse(base.template)
+		if err != nil {
+			return nil, base.errWithFileContext("parse failed", err)
+		}
 	}
 
 	templ, err = htmltemplate.Must(templ.Clone()).Parse(overlay.template)

tpl/tplimpl/template_errors.go

@@ -34,6 +34,10 @@ type templateInfo struct {
 	realFilename string
 }
 
+func (t templateInfo) IsZero() bool {
+	return t.name == ""
+}
+
 func (t templateInfo) resolveType() templateType {
 	return resolveTemplateType(t.name)
 }