template/interpolate: filter is case insensitive

template/interpolate/render.go

@@ -74,14 +74,14 @@ func (f *RenderFilter) include(k string) bool {
 	}
 
 	f.once.Do(f.init)
-	_, ok := f.includeSet[k]
+	_, ok := f.includeSet[strings.ToLower(k)]
 	return ok
 }
 
 func (f *RenderFilter) init() {
 	f.includeSet = make(map[string]struct{})
 	for _, v := range f.Include {
-		f.includeSet[v] = struct{}{}
+		f.includeSet[strings.ToLower(v)] = struct{}{}
 	}
 }
 

template/interpolate/render_test.go

@@ -76,6 +76,24 @@ func TestRenderMap(t *testing.T) {
 				Include: []string{"bar"},
 			},
 		},
+
+		"filter case-insensitive": {
+			map[string]interface{}{
+				"bar": "{{upper `baz`}}",
+				"foo": map[string]string{
+					"{{upper `bar`}}": "{{upper `baz`}}",
+				},
+			},
+			map[string]interface{}{
+				"bar": "BAZ",
+				"foo": map[string]string{
+					"{{upper `bar`}}": "{{upper `baz`}}",
+				},
+			},
+			&RenderFilter{
+				Include: []string{"baR"},
+			},
+		},
 	}
 
 	ctx := &Context{}