fix: isolate template render parse state (#10365)

Fix empty file-template render isolation by cloning the template per ConfigMap key and keeping direct map iteration after review.

Author: weicao

controllers/apps/component/transformer_component_template.go

@@ -314,7 +314,11 @@ func (t *componentFileTemplateTransformer) renderFileTemplateData(transCtx *comp
 
 	tpl := template.New(fileTemplate.Name).Option("missingkey=error").Funcs(sprig.TxtFuncMap())
 	for key, val := range data {
-		ptpl, err := tpl.Parse(val)
+		ptpl, err := tpl.Clone()
+		if err != nil {
+			return nil, err
+		}
+		ptpl, err = ptpl.Parse(val)
 		if err != nil {
 			return nil, err
 		}

controllers/apps/component/transformer_component_template_test.go

@@ -280,6 +280,22 @@ var _ = Describe("file templates transformer test", func() {
 			})
 		})
 
+		It("keeps empty template file content empty", func() {
+			logConfCM.Data["member_leave.sh"] = "member_leave"
+			logConfCM.Data["role_probe.sh"] = "role_probe"
+			logConfCM.Data["switchover.sh"] = ""
+
+			transformer := &componentFileTemplateTransformer{}
+			Expect(transformer.Transform(transCtx, dag)).Should(BeNil())
+
+			checkTemplateObject("logConf", func(obj *corev1.ConfigMap) {
+				Expect(obj.Labels).Should(HaveKeyWithValue(kubeBlockFileTemplateLabelKey, "true"))
+				Expect(obj.Data).Should(HaveKeyWithValue("member_leave.sh", "member_leave"))
+				Expect(obj.Data).Should(HaveKeyWithValue("role_probe.sh", "role_probe"))
+				Expect(obj.Data).Should(HaveKeyWithValue("switchover.sh", ""))
+			})
+		})
+
 		It("udf reconfigure", func() {
 			transCtx.SynthesizeComponent.FileTemplates[0].ReconfigureRequired = ptr.To(true)
 			transCtx.SynthesizeComponent.FileTemplates[0].ReconfigureAction = &appsv1.Action{

pkg/gotemplate/tpl_engine.go

@@ -113,7 +113,11 @@ func (t *TplEngine) GetTplEngine() *template.Template {
 
 func (t *TplEngine) Render(context string) (string, error) {
 	var buf strings.Builder
-	tpl, err := t.tpl.Parse(context)
+	tpl, err := t.tpl.Clone()
+	if err != nil {
+		return "", err
+	}
+	tpl, err = tpl.Parse(context)
 	if err != nil {
 		return "", err
 	}

pkg/gotemplate/tpl_engine_test.go

@@ -83,6 +83,26 @@ my friend name is test2
 			Expect(err).NotTo(HaveOccurred())
 			Expect(context).To(Equal(expectString))
 		})
+
+		It("Should render empty template content as empty", func() {
+			engine := NewTplEngine(&TplValues{}, nil, "for_test", nil, nil)
+
+			rendered, err := engine.Render("member-leave")
+			Expect(err).Should(Succeed())
+			Expect(rendered).Should(Equal("member-leave"))
+
+			rendered, err = engine.Render("")
+			Expect(err).Should(Succeed())
+			Expect(rendered).Should(Equal(""))
+
+			rendered, err = engine.Render("role-probe")
+			Expect(err).Should(Succeed())
+			Expect(rendered).Should(Equal("role-probe"))
+
+			rendered, err = engine.Render("")
+			Expect(err).Should(Succeed())
+			Expect(rendered).Should(Equal(""))
+		})
 	})
 
 	// A call funcB.1 in B module