Fix server reload when non-HTML shortcode changes

Fixes #7448

tpl/collections/apply_test.go

@@ -40,6 +40,10 @@ func (templateFinder) LookupVariant(name string, variants tpl.TemplateVariants)
 	return nil, false, false
 }
 
+func (templateFinder) LookupVariants(name string) []tpl.Template {
+	return nil
+}
+
 func (templateFinder) LookupLayout(d output.LayoutDescriptor, f output.Format) (tpl.Template, bool, error) {
 	return nil, false, nil
 }

tpl/template.go

@@ -68,6 +68,7 @@ type TemplateLookupVariant interface {
 	// We are currently only interested in output formats, so we should improve
 	// this for speed.
 	LookupVariant(name string, variants TemplateVariants) (Template, bool, bool)
+	LookupVariants(name string) []Template
 }
 
 // Template is the common interface between text/template and html/template.

tpl/tplimpl/template.go

@@ -354,6 +354,23 @@ func (t *templateHandler) LookupVariant(name string, variants tpl.TemplateVarian
 
 }
 
+// LookupVariants returns all variants of name, nil if none found.
+func (t *templateHandler) LookupVariants(name string) []tpl.Template {
+	name = templateBaseName(templateShortcode, name)
+	s, found := t.shortcodes[name]
+	if !found {
+		return nil
+	}
+
+	variants := make([]tpl.Template, len(s.variants))
+	for i := 0; i < len(variants); i++ {
+		variants[i] = s.variants[i].ts
+	}
+
+	return variants
+
+}
+
 func (t *templateHandler) HasTemplate(name string) bool {
 
 	if _, found := t.baseof[name]; found {
@@ -966,6 +983,10 @@ func (t *textTemplateWrapperWithLock) LookupVariant(name string, variants tpl.Te
 	panic("not supported")
 }
 
+func (t *textTemplateWrapperWithLock) LookupVariants(name string) []tpl.Template {
+	panic("not supported")
+}
+
 func (t *textTemplateWrapperWithLock) Parse(name, tpl string) (tpl.Template, error) {
 	t.Lock()
 	defer t.Unlock()