{"record":{"id":"8b5d77ae66664e8a","repo":"gofiber/fiber","slug":"failed-to-render-w","errorCode":null,"errorMessage":"failed to render: %w","messagePattern":"failed to render: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"res.go","lineNumber":921,"sourceCode":"\tvar rendered bool\n\tfor _, prefix := range slices.Backward(rootApp.mountFields.appListKeys) {\n\t\tapp := rootApp.mountFields.appList[prefix]\n\t\tif prefix == \"\" || strings.Contains(r.c.OriginalURL(), prefix) {\n\t\t\tif len(layouts) == 0 && app.config.ViewsLayout != \"\" {\n\t\t\t\tlayouts = []string{\n\t\t\t\t\tapp.config.ViewsLayout,\n\t\t\t\t}\n\t\t\t}\n\n\t\t\t// Render template from Views\n\t\t\tif app.config.Views != nil {\n\t\t\t\tif err := func() error {\n\t\t\t\t\tviewsLock := getViewsLock(app.config.Views)\n\t\t\t\t\tviewsLock.RLock()\n\t\t\t\t\tdefer viewsLock.RUnlock()\n\n\t\t\t\t\tif err := app.config.Views.Render(buf, name, bind, layouts...); err != nil {\n\t\t\t\t\t\treturn fmt.Errorf(\"failed to render: %w\", err)\n\t\t\t\t\t}\n\n\t\t\t\t\treturn nil\n\t\t\t\t}(); err != nil {\n\t\t\t\t\treturn err\n\t\t\t\t}\n\n\t\t\t\trendered = true\n\t\t\t\tbreak\n\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","sourceCodeStart":903,"sourceCodeEnd":939,"githubUrl":"https://github.com/gofiber/fiber/blob/a105acad6c1e4576a77f01e02973f67e962bb58d/res.go#L903-L939","documentation":"Returned by DefaultRes.Render() when a configured Views engine (the github.com/gofiber/template family) fails its Render call. Fiber wraps the engine error with 'failed to render' so the call site is identifiable; the underlying %w carries the engine-specific cause. The RLock held on the views lock is released via defer before the error propagates.","triggerScenarios":"Calling ctx.Render(name, bind) or res.Render(name, bind) where app.config.Views is non-nil, and the engine's Render() returns an error: template file not loaded/registered, template syntax error, missing partial/layout referenced in ViewsLayout, or a binding type the engine rejects.","commonSituations":"Forgot to call Views.Load() or the engine failed to find the template directory; template filename typo; layout referenced in Config.ViewsLayout does not exist; version mismatch between fiber/v3 and a gofiber/template engine whose Render signature changed; passing a bind struct whose fields/methods the template references incorrectly.","solutions":["Check the wrapped error (errors.Unwrap) for the engine-specific message — it names the missing template or the parse line.","Ensure Views.Load() is called and returns nil before the server starts; verify the templates root path is correct.","Confirm every layout name passed to Render() (and the global ViewsLayout) exists as a registered template.","If using an embed.FS, verify the //go:embed directive includes every .tmpl/.hbs file the engine references.","Pin gofiber/template/<engine> to a version compatible with your fiber/v3 minor."],"exampleFix":"// before: template path wrong, engine cannot find it\napp := fiber.New(fiber.Config{\n    Views: html.New(\"./views\", \".html\"), // actual dir is ./templates\n})\napp.Get(\"/\", func(c fiber.Ctx) error {\n    return c.Render(\"index\", fiber.Map{}) // failed to render: ...\n})\n\n// after\napp := fiber.New(fiber.Config{\n    Views: html.New(\"./templates\", \".html\"),\n})\nif err := app.Config().Views.Load(); err != nil {\n    log.Fatal(err)\n}","handlingStrategy":"try-catch","validationCode":"// Validate the engine and templates before serving traffic.\nif app.Config().Views != nil {\n    if err := app.Config().Views.Load(); err != nil {\n        log.Fatal(\"views load failed: \", err)\n    }\n}\n// Smoke-render critical templates at startup.\nprobe := new(bytes.Buffer)\nif err := app.Config().Views.Render(probe, \"index\", fiber.Map{}); err != nil {\n    log.Fatal(\"smoke render failed: \", err)\n}","typeGuard":null,"tryCatchPattern":"// In the handler: distinguish render errors from other failures.\nif err := c.Render(name, bind); err != nil {\n    var fe *fiber.Error\n    if errors.As(err, &fe) {\n        return err // pass through fiber errors\n    }\n    log.Printf(\"render %q failed: %v\", name, err)\n    return fiber.ErrInternalServerError\n}","preventionTips":["Call Views.Load() at startup and fail fast on error.","Smoke-test render every critical template in a unit test.","Pin gofiber/template engine versions to match your fiber/v3 minor.","Treat layout names (ViewsLayout) as code: track them in tests."],"tags":["rendering","template-engine","views","html"],"backgroundTag":null,"analyzedSha":"a105acad6c1e4576a77f01e02973f67e962bb58d","analyzedAt":"2026-08-11T17:33:26.942Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}