chore: import upstream snapshot with attribution

cmd/root_upgrade.go

@@ -0,0 +1,90 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/larksuite/cli/internal/build"
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/update"
+	"github.com/spf13/cobra"
+)
+
+// runRootUpgrade locates the registered `update` subcommand and runs it, so the
+// interactive root-command upgrade reuses exactly `lark-cli update` behavior
+// (install-method detection, output, error handling). Package-level var so
+// tests can stub it and avoid real network / self-update.
+var runRootUpgrade = func(cmd *cobra.Command) {
+	for _, c := range cmd.Root().Commands() {
+		if c.Name() == "update" && c.RunE != nil {
+			_ = c.RunE(c, nil) // update prints its own output/errors; swallow here
+			return
+		}
+	}
+}
+
+// isBareRootInvocation reports whether this is a bare `lark-cli` (no subcommand,
+// no flags) — the only invocation that triggers the interactive upgrade prompt.
+// Mirrors unknownSubcommandRunE's "bare group prints help" branch: args empty
+// AND no flag tokens in the raw invocation.
+func isBareRootInvocation(args []string) bool {
+	return len(args) == 0 && len(flagTokensInArgs(rawInvocationArgs)) == 0
+}
+
+// readYes reads one line and reports whether it is an affirmative y/yes.
+// EOF / empty / anything else → false (default No, matching the [y/N] prompt).
+func readYes(r io.Reader) bool {
+	line, _ := bufio.NewReader(r).ReadString('\n')
+	switch strings.ToLower(strings.TrimSpace(line)) {
+	case "y", "yes":
+		return true
+	default:
+		return false
+	}
+}
+
+// offerRootUpgrade prompts for an interactive upgrade when running bare
+// `lark-cli` in an interactive terminal with a cached newer version. Every
+// failure is swallowed — it must never affect help output or the exit code.
+func offerRootUpgrade(f *cmdutil.Factory, cmd *cobra.Command) {
+	ios := f.IOStreams
+	// Gates 1/2/3: need to read stdin AND show the prompt on stderr, and require
+	// stdout TTY too so this only fires in a pure foreground terminal session.
+	if !ios.IsTerminal || !ios.OutIsTerminal || !ios.StderrIsTerminal {
+		return
+	}
+	// Gate 4: cached newer version. CheckCached applies opt-out (shouldSkip)
+	// and the IsNewer/semver validation chain; it reads the on-disk cache that
+	// the 24h-throttled RefreshCache maintains (CheckCached itself has no TTL).
+	info := update.CheckCached(build.Version)
+	if info == nil {
+		return
+	}
+	fmt.Fprintf(ios.ErrOut, "lark-cli %s available (current %s). Upgrade now? [y/N]: ", info.Latest, info.Current)
+	if !readYes(ios.In) {
+		return
+	}
+	runRootUpgrade(cmd)
+}
+
+// installRootUpgradePrompt wraps the root command's RunE (set to
+// unknownSubcommandRunE by installUnknownSubcommandGuard) so a bare `lark-cli`
+// invocation offers an interactive upgrade before printing help. Non-bare
+// invocations are passed straight through, unchanged.
+func installRootUpgradePrompt(f *cmdutil.Factory, root *cobra.Command) {
+	inner := root.RunE
+	if inner == nil {
+		return
+	}
+	root.RunE = func(cmd *cobra.Command, args []string) error {
+		if isBareRootInvocation(args) {
+			offerRootUpgrade(f, cmd)
+		}
+		return inner(cmd, args)
+	}
+}