func migrate()

in core/core.go [532:598]
58 lines of code
9 McCabe index (conditional complexity)

func migrate(bazelPath string, baseArgs []string, flags []string) {
	// 1. Try with all the flags.
	args := insertArgs(baseArgs, flags)
	fmt.Printf("\n\n--- Running Bazel with all incompatible flags\n\n")
	shutdownIfNeeded(bazelPath)
	cleanIfNeeded(bazelPath)
	fmt.Printf("bazel %s\n", strings.Join(args, " "))
	exitCode, err := runBazel(bazelPath, args, nil)
	if err != nil {
		log.Fatalf("could not run Bazel: %v", err)
	}
	if exitCode == 0 {
		fmt.Printf("Success: No migration needed.\n")
		os.Exit(0)
	}

	// 2. Try with no flags, as a sanity check.
	args = baseArgs
	fmt.Printf("\n\n--- Running Bazel with no incompatible flags\n\n")
	shutdownIfNeeded(bazelPath)
	cleanIfNeeded(bazelPath)
	fmt.Printf("bazel %s\n", strings.Join(args, " "))
	exitCode, err = runBazel(bazelPath, args, nil)
	if err != nil {
		log.Fatalf("could not run Bazel: %v", err)
	}
	if exitCode != 0 {
		fmt.Printf("Failure: Command failed, even without incompatible flags.\n")
		os.Exit(exitCode)
	}

	// 3. Try with each flag separately.
	var passList []string
	var failList []string
	for _, arg := range flags {
		args = insertArgs(baseArgs, []string{arg})
		fmt.Printf("\n\n--- Running Bazel with %s\n\n", arg)
		shutdownIfNeeded(bazelPath)
		cleanIfNeeded(bazelPath)
		fmt.Printf("bazel %s\n", strings.Join(args, " "))
		exitCode, err = runBazel(bazelPath, args, nil)
		if err != nil {
			log.Fatalf("could not run Bazel: %v", err)
		}
		if exitCode == 0 {
			passList = append(passList, arg)
		} else {
			failList = append(failList, arg)
		}
	}

	print := func(l []string) {
		for _, arg := range l {
			fmt.Printf("  %s\n", arg)
		}
	}

	// 4. Print report
	fmt.Printf("\n\n+++ Result\n\n")
	fmt.Printf("Command was successful with the following flags:\n")
	print(passList)
	fmt.Printf("\n")
	fmt.Printf("Migration is needed for the following flags:\n")
	print(failList)

	os.Exit(1)
}