fix(engine): clone Template for tpl

See https://github.com/helm/helm/issues/8002

Signed-off-by: Ivan Mikheykin <ivan.mikheykin@flant.com>

pkg/engine/engine.go

@@ -104,7 +104,7 @@ func warnWrap(warn string) string {
 }
 
 // initFunMap creates the Engine's FuncMap and adds context-specific functions.
-func (e Engine) initFunMap(t *template.Template, referenceTpls map[string]renderable) {
+func (e Engine) initFunMap(t *template.Template) {
 	funcMap := funcMap()
 	includedNames := make(map[string]int)
 
@@ -144,7 +144,12 @@ func (e Engine) initFunMap(t *template.Template, referenceTpls map[string]render
 			},
 		}
 
-		result, err := e.renderWithReferences(templates, referenceTpls)
+		clone, err := t.Clone()
+		if err != nil {
+			return "", errors.Errorf("clone template failed: %v", err)
+		}
+
+		result, err := e.renderWithTemplate(templates, clone)
 		if err != nil {
 			return "", errors.Wrapf(err, "error during tpl function execution for %q", tpl)
 		}
@@ -184,12 +189,21 @@ func (e Engine) initFunMap(t *template.Template, referenceTpls map[string]render
 
 // render takes a map of templates/values and renders them.
 func (e Engine) render(tpls map[string]renderable) (map[string]string, error) {
-	return e.renderWithReferences(tpls, tpls)
+	t := template.New("gotpl")
+	if e.Strict {
+		t.Option("missingkey=error")
+	} else {
+		// Not that zero will attempt to add default values for types it knows,
+		// but will still emit <no value> for others. We mitigate that later.
+		t.Option("missingkey=zero")
+	}
+
+	return e.renderWithTemplate(tpls, t)
 }
 
-// renderWithReferences takes a map of templates/values to render, and a map of
-// templates which can be referenced within them.
-func (e Engine) renderWithReferences(tpls, referenceTpls map[string]renderable) (rendered map[string]string, err error) {
+// renderWithTemplate takes a map of templates/values to render using
+// passed Template object.
+func (e Engine) renderWithTemplate(tpls map[string]renderable, t *template.Template) (rendered map[string]string, err error) {
 	// Basically, what we do here is start with an empty parent template and then
 	// build up a list of templates -- one for each file. Once all of the templates
 	// have been parsed, we loop through again and execute every template.
@@ -197,26 +211,20 @@ func (e Engine) renderWithReferences(tpls, referenceTpls map[string]renderable)
 	// The idea with this process is to make it possible for more complex templates
 	// to share common blocks, but to make the entire thing feel like a file-based
 	// template engine.
+	//
+	// Template from tpl function is a dublicate, so defines in tpl are not interfered
+	// with defines in "real" templates.
 	defer func() {
 		if r := recover(); r != nil {
 			err = errors.Errorf("rendering template failed: %v", r)
 		}
 	}()
-	t := template.New("gotpl")
-	if e.Strict {
-		t.Option("missingkey=error")
-	} else {
-		// Not that zero will attempt to add default values for types it knows,
-		// but will still emit <no value> for others. We mitigate that later.
-		t.Option("missingkey=zero")
-	}
 
-	e.initFunMap(t, referenceTpls)
+	e.initFunMap(t)
 
 	// We want to parse the templates in a predictable order. The order favors
 	// higher-level (in file system) templates over deeply nested templates.
 	keys := sortTemplates(tpls)
-	referenceKeys := sortTemplates(referenceTpls)
 
 	for _, filename := range keys {
 		r := tpls[filename]
@@ -225,17 +233,6 @@ func (e Engine) renderWithReferences(tpls, referenceTpls map[string]renderable)
 		}
 	}
 
-	// Adding the reference templates to the template context
-	// so they can be referenced in the tpl function
-	for _, filename := range referenceKeys {
-		if t.Lookup(filename) == nil {
-			r := referenceTpls[filename]
-			if _, err := t.New(filename).Parse(r.tpl); err != nil {
-				return map[string]string{}, cleanupParseError(filename, err)
-			}
-		}
-	}
-
 	rendered = make(map[string]string, len(keys))
 	for _, filename := range keys {
 		// Don't render partials. We don't care out the direct output of partials.

pkg/engine/engine_test.go

@@ -738,3 +738,38 @@ func TestRenderRecursionLimit(t *testing.T) {
 	}
 
 }
+
+func TestRenderLoadTemplateForTplFromFile(t *testing.T) {
+	c := &chart.Chart{
+		Metadata: &chart.Metadata{Name: "TplLoadFromFile"},
+		Templates: []*chart.File{
+			{Name: "templates/base", Data: []byte(`{{ tpl (.Files.Get .Values.filename) . }}`)},
+			{Name: "templates/_function", Data: []byte(`{{define "test-function"}}test-function{{end}}`)},
+		},
+		Files: []*chart.File{
+			{Name: "test", Data: []byte(`{{ tpl (.Files.Get .Values.filename2) .}}`)},
+			{Name: "test2", Data: []byte(`{{include "test-function" .}}{{define "nested-define"}}nested-define-content{{end}} {{include "nested-define" .}}`)},
+		},
+	}
+
+	v := chartutil.Values{
+		"Values": chartutil.Values{
+			"filename":  "test",
+			"filename2": "test2",
+		},
+		"Chart": c.Metadata,
+		"Release": chartutil.Values{
+			"Name": "TestRelease",
+		},
+	}
+
+	out, err := Render(c, v)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expect := "test-function nested-define-content"
+	if got := out["TplLoadFromFile/templates/base"]; got != expect {
+		t.Fatalf("Expected %q, got %q", expect, got)
+	}
+}