chore: import upstream snapshot with attribution

internal/cmdutil/completion.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package cmdutil
+
+import (
+	"sync/atomic"
+
+	"github.com/spf13/cobra"
+)
+
+// Cobra keeps completion callbacks in a package-global map keyed by
+// *pflag.Flag with no removal path, so registrations made for a *cobra.Command
+// outlive the command itself. Default to disabled (zero value = false) and let
+// callers that actually serve a completion request opt in via
+// SetFlagCompletionsEnabled(true).
+var flagCompletionsEnabled atomic.Bool
+
+// SetFlagCompletionsEnabled toggles whether RegisterFlagCompletion actually
+// registers callbacks with cobra. Typically set once at process start.
+func SetFlagCompletionsEnabled(enabled bool) {
+	flagCompletionsEnabled.Store(enabled)
+}
+
+// FlagCompletionsEnabled reports the current switch state.
+func FlagCompletionsEnabled() bool {
+	return flagCompletionsEnabled.Load()
+}
+
+// RegisterFlagCompletion wraps (*cobra.Command).RegisterFlagCompletionFunc
+// and honors the package switch. The underlying error is swallowed to match
+// the `_ = cmd.RegisterFlagCompletionFunc(...)` style already used here.
+func RegisterFlagCompletion(cmd *cobra.Command, flagName string, fn cobra.CompletionFunc) {
+	if !flagCompletionsEnabled.Load() {
+		return
+	}
+	_ = cmd.RegisterFlagCompletionFunc(flagName, fn)
+}