{"id":"2c2d12ea6bc8c11d","repo":"gofiber/fiber","slug":"failed-to-execute-w","errorCode":null,"errorMessage":"failed to execute: %w","messagePattern":"failed to execute: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"res.go","lineNumber":797,"sourceCode":"\t\t\t}\n\t\t}\n\t}\n\n\tif !rendered {\n\t\t// Render raw template using 'name' as filepath if no engine is set\n\t\tvar tmpl *template.Template\n\t\tif _, err := readContent(buf, name); err != nil {\n\t\t\treturn err\n\t\t}\n\t\t// Parse template\n\t\ttmpl, err := template.New(\"\").Parse(rootApp.toString(buf.Bytes()))\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"failed to parse: %w\", err)\n\t\t}\n\t\tbuf.Reset()\n\t\t// Render template\n\t\tif err := tmpl.Execute(buf, bind); err != nil {\n\t\t\treturn fmt.Errorf(\"failed to execute: %w\", err)\n\t\t}\n\t}\n\n\tresponse := &r.c.fasthttp.Response\n\n\t// Set Content-Type to text/html\n\tresponse.Header.SetContentType(MIMETextHTMLCharsetUTF8)\n\t// Set rendered template to body\n\tresponse.SetBody(buf.Bytes())\n\n\treturn nil\n}\n\nfunc (r *DefaultRes) renderExtensions(bind any) {\n\tr.c.renderExtensions(bind)\n}\n\n// Send sets the HTTP response body without copying it.","sourceCodeStart":779,"sourceCodeEnd":815,"githubUrl":"https://github.com/gofiber/fiber/blob/9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c/res.go#L779-L815","documentation":"In Render's fallback path, after parsing, executing the template against bind failed. This is a template runtime error: referencing a field/method that doesn't exist on the bind, a nil pointer in a pipeline, a bad type assertion, or an index out of range in a {{range}}.","triggerScenarios":"Template references {{ .User.Name }} but bind (or .User) is nil or missing the field; calling a method not defined on the bind type; {{ index .Arr 5 }} with too few elements.","commonSituations":"Bind struct changed but template not updated; nil nested fields; passing a Map missing expected keys; type mismatches after refactors.","solutions":["Ensure the bind value exposes every field/method the template references.","Guard optional values in the template with {{ if .User }}...{{ end }}.","Keep the bind type and the template in sync; add a render test."],"exampleFix":"// before: bind = fiber.Map{\"title\": \"Hi\"}  template: {{ .User.Name }}\n//   -> failed to execute: nil has no fields\n\n// after:  bind = fiber.Map{\"title\": \"Hi\", \"user\": u}\n//   template: {{ if .User }}{{ .User.Name }}{{ end }}","handlingStrategy":"validation","validationCode":"// render into a buffer in a test to surface execution errors early\nfunc TestRender(t *testing.T) {\n    app := fiber.New()\n    c := app.AcquireCtx(&fasthttp.RequestCtx{})\n    defer app.ReleaseCtx(c)\n    if err := c.Render(\"tpl\", bind); err != nil { t.Fatal(err) }\n}","typeGuard":null,"tryCatchPattern":"if err := c.Render(name, bind); err != nil {\n    log.Errorf(\"execute %q failed: %v\", name, err)\n    return c.Status(fiber.StatusInternalServerError).\n        SendString(\"template error\")\n}","preventionTips":["Keep bind types and templates in lockstep.","Guard nil/optional fields with {{ if }}.","Add a render smoke test per route."],"tags":["template","execute","fiber"],"analyzedSha":"9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c","analyzedAt":"2026-08-04T21:44:03.395Z","schemaVersion":2}