{"record":{"id":"be8bfb4da57ee09c","repo":"gofiber/fiber","slug":"missing-handler-middleware-in-route-s","errorCode":null,"errorMessage":"missing handler/middleware in route: %s\n","messagePattern":"missing handler/middleware in route: (.+?)\n","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"router.go","lineNumber":998,"sourceCode":"\tnorm := app.normalizePath(path)\n\n\theadStack := app.stack[headIndex]\n\tfor i, headRoute := range slices.Backward(headStack) {\n\t\tif headRoute.path != norm || headRoute.mount || headRoute.use || !headRoute.autoHead {\n\t\t\tcontinue\n\t\t}\n\n\t\tapp.stack[headIndex] = append(headStack[:i], headStack[i+1:]...)\n\t\tapp.hasRoutesRefreshed = true\n\t\tatomic.AddUint32(&app.handlersCount, ^uint32(len(headRoute.Handlers)-1)) //nolint:gosec // G115 - handler count is always small\n\t\treturn\n\t}\n}\n\nfunc (app *App) register(methods []string, pathRaw string, group *Group, handlers ...Handler) {\n\t// A regular route requires at least one ctx handler\n\tif len(handlers) == 0 && group == nil {\n\t\tpanic(fmt.Sprintf(\"missing handler/middleware in route: %s\\n\", pathRaw))\n\t}\n\t// No nil handlers allowed\n\tfor _, h := range handlers {\n\t\tif h == nil {\n\t\t\tpanic(fmt.Sprintf(\"nil handler in route: %s\\n\", pathRaw))\n\t\t}\n\t}\n\n\t// Precompute path normalization ONCE\n\tif pathRaw == \"\" {\n\t\tpathRaw = \"/\"\n\t}\n\tif pathRaw[0] != '/' {\n\t\tpathRaw = \"/\" + pathRaw\n\t}\n\tpathPretty := pathRaw\n\tif !app.config.CaseSensitive {\n\t\tpathPretty = utilsstrings.ToLower(pathPretty)","sourceCodeStart":980,"sourceCodeEnd":1016,"githubUrl":"https://github.com/gofiber/fiber/blob/a105acad6c1e4576a77f01e02973f67e962bb58d/router.go#L980-L1016","documentation":"The internal register function requires at least one handler for a regular (non-group, non-mount) route. Calling a registration method (Get, Post, Use, etc.) with zero handler arguments and no surrounding Group panics with \"missing handler/middleware in route: <path>\". This catches a common mistake — declaring a route but forgetting to attach a handler — at startup rather than serving a silent no-op.","triggerScenarios":"app.Get(\"/users\") with no handler argument; app.Use(\"/api\") with no middleware; any registration call where the handlers variadic is empty and the call is not inside a Group chain.","commonSituations":"Refactoring that moved the handler into a variable that turned out nil/empty; a copy-paste that dropped the handler argument; a conditional registration where the handler slice was empty.","solutions":["Supply at least one fiber.Handler (or handler-returning call) to every registration method.","If conditionally adding middleware, ensure the variadic always contains at least one element, or skip the registration entirely when the list is empty.","Enable static analysis / review checks that flag bare app.Method(path) calls."],"exampleFix":"// before\napp.Get(\"/users\") // panics: no handler\n\n// after\napp.Get(\"/users\", listUsers)","handlingStrategy":"validation","validationCode":"func mustRegister(app *fiber.App, method, path string, handlers ...fiber.Handler) {\n    if len(handlers) == 0 {\n        log.Fatalf(\"route %s %s has no handler\", method, path)\n    }\n    app.Add(method, path, handlers...)\n}","typeGuard":"func hasAtLeastOneHandler(handlers []fiber.Handler) bool { return len(handlers) > 0 }","tryCatchPattern":null,"preventionTips":["Review every app.Method(path) call to confirm a handler argument follows.","For conditional middleware, skip the registration when the list is empty instead of relying on the panic."],"tags":["router","config","panic","routing"],"backgroundTag":null,"analyzedSha":"a105acad6c1e4576a77f01e02973f67e962bb58d","analyzedAt":"2026-08-11T17:33:26.942Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}