Previously, kubectx would error with "multiple files in KUBECONFIG are
currently not supported" when KUBECONFIG contained colon-separated paths.
This is a common setup where users maintain separate kubeconfig files for
different clusters/environments.
This change evolves the internal Kubeconfig struct from holding a single
file to a slice of file entries, matching kubectl's merge semantics:
- Reading current-context: first file with a non-empty value wins
- Writing current-context: always written to the first file
- Listing contexts: merged from all files, first occurrence wins for
duplicate names
- Modifying a context (delete/rename/set-namespace): written to the
file that owns that context
- Missing files in the KUBECONFIG list are silently skipped (matching
kubectl behavior), but permission errors are propagated
The Loader interface already returned []ReadWriteResetCloser, so all
public method signatures remain unchanged — zero modifications needed
in cmd/kubectx/ or cmd/kubens/ callers.
Fixes#485Fixes#211
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
t.Setenv is the modern standard Go testing utility (since Go 1.17) that automatically restores environment variables when the test completes. This replaces the custom testutil.WithEnvVar function which manually saved and restored env var state.
The testutil.go file is deleted as it only contained WithEnvVar. The testutil package remains for its other utilities like KubeconfigBuilder.
