{"record":{"id":"262e4f5be0d24432","repo":"ahmetb/kubectx","slug":"failed-to-change-to-namespace-s-w","errorCode":null,"errorMessage":"failed to change to namespace \"%s\": %w","messagePattern":"failed to change to namespace \"(.+?)\": %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"cmd/kubens/switch.go","lineNumber":88,"sourceCode":"\tif ns == \"-\" {\n\t\tif prev == \"\" {\n\t\t\treturn \"\", fmt.Errorf(\"No previous namespace found for current context (%s)\", ctx)\n\t\t}\n\t\tns = prev\n\t}\n\n\tif !force {\n\t\tok, err := namespaceExists(kc, ns)\n\t\tif err != nil {\n\t\t\treturn \"\", fmt.Errorf(\"failed to query if namespace exists (is cluster accessible?): %w\", err)\n\t\t}\n\t\tif !ok {\n\t\t\treturn \"\", fmt.Errorf(\"no namespace exists with name \\\"%s\\\"\", ns)\n\t\t}\n\t}\n\n\tif err := kc.SetNamespace(ctx, ns); err != nil {\n\t\treturn \"\", fmt.Errorf(\"failed to change to namespace \\\"%s\\\": %w\", ns, err)\n\t}\n\tif err := kc.Save(); err != nil {\n\t\treturn \"\", fmt.Errorf(\"failed to save kubeconfig file: %w\", err)\n\t}\n\tif curNS != ns {\n\t\tif err := f.Save(curNS); err != nil {\n\t\t\treturn \"\", fmt.Errorf(\"failed to save the previous namespace to file: %w\", err)\n\t\t}\n\t}\n\treturn ns, nil\n}\n\nfunc namespaceExists(kc *kubeconfig.Kubeconfig, ns string) (bool, error) {\n\t// for tests\n\tif os.Getenv(\"_MOCK_NAMESPACES\") != \"\" {\n\t\treturn ns == \"ns1\" || ns == \"ns2\", nil\n\t}\n","sourceCodeStart":70,"sourceCodeEnd":106,"githubUrl":"https://github.com/ahmetb/kubectx/blob/12ad6fb22e8c546ee2b54e7de38aa51c906832f7/cmd/kubens/switch.go#L70-L106","documentation":"Once the target namespace is validated, switchNamespace calls kc.SetNamespace(ctx, ns) to write the namespace field onto the current context in the in-memory kubeconfig. This error wraps any failure of that mutation, which in this client occurs when the referenced context cannot be found or the kubeconfig structure is unexpected. Thrown at cmd/kubens/switch.go:88.","triggerScenarios":"kc.SetNamespace(ctx, ns) errors because the context identified by ctx is not present in the kubeconfig's contexts list at the time of mutation (e.g. the config was reloaded/changed between the read and write), or an internal structure mismatch.","commonSituations":"Concurrent modification of the kubeconfig by another process (kubectl use-context, cloud auth tooling rewriting the file) between the existence check and the set; hand-edited kubeconfig that dropped the context mid-session.","solutions":["Re-run kubens — a transient concurrent-modification race usually resolves on retry","Confirm the context still exists: kubectl config get-contexts; re-create it with kubectl config set-context if removed","Avoid running multiple kubeconfig-mutating commands in parallel (kubectl, kubectx, cloud CLIs)"],"exampleFix":"// before\nkubens prod   # fails: context vanished mid-run (another tool rewrote kubeconfig)\n// after\nkubectl config get-contexts   # verify context present\nkubens prod                   # retry the switch","handlingStrategy":"retry","validationCode":"// re-read the config right before mutating to close the race\nkc2 := new(kubeconfig.Kubeconfig).WithLoader(kubeconfig.DefaultLoader)\nif err := kc2.Parse(); err != nil { return err }\nif _, err := kc2.ContextOf(ctx); err != nil { return fmt.Errorf(\"context %q gone\", ctx) }","typeGuard":null,"tryCatchPattern":"if err := kc.SetNamespace(ctx, ns); err != nil {\n    // likely concurrent kubeconfig modification; re-parse and retry once\n    if err := kc.Parse(); err == nil {\n        if err := kc.SetNamespace(ctx, ns); err == nil { return nil }\n    }\n    return err\n}","preventionTips":["Do not run kubectx/kubectl use-context/cloud auth tools concurrently with kubens","Serialize kubeconfig mutations through one tool per shell session","Re-run the command after external tooling finishes rewriting the kubeconfig"],"tags":["kubeconfig","go","kubens"],"backgroundTag":"kubeconfig-context-missing","analyzedSha":"12ad6fb22e8c546ee2b54e7de38aa51c906832f7","analyzedAt":"2026-09-02T12:23:10.107Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T16:17:10.729Z"}