func runInDir()

in reflect.go [86:138]
42 lines of code
9 McCabe index (conditional complexity)

func runInDir(program []byte, dir string) (*model.PackedPkg, error) {
	// We use TempDir instead of TempFile so we can control the filename.
	tmpDir, err := ioutil.TempDir(dir, "depstubber_reflect_")
	if err != nil {
		return nil, err
	}
	defer func() {
		if err := os.RemoveAll(tmpDir); err != nil {
			log.Printf("failed to remove temp directory: %s", err)
		}
	}()
	const progSource = "prog.go"
	var progBinary = "prog.bin"
	if runtime.GOOS == "windows" {
		// Windows won't execute a program unless it has a ".exe" suffix.
		progBinary += ".exe"
	}

	if err := ioutil.WriteFile(filepath.Join(tmpDir, progSource), program, 0600); err != nil {
		return nil, err
	}

	{
		// Copy go.mod into the build directory:
		wd, err := os.Getwd()
		if err != nil {
			log.Fatalf("Unable to load current directory: %v", err)
		}

		modRoot := findModuleRoot(wd)

		if modRoot != "" {
			MustCopyFile(filepath.Join(modRoot, "go.mod"), filepath.Join(tmpDir, "go.mod"))
		}
	}

	cmdArgs := []string{"build", "-mod=mod"}
	if *buildFlags != "" {
		cmdArgs = append(cmdArgs, strings.Split(*buildFlags, " ")...)
	}
	cmdArgs = append(cmdArgs, "-o", progBinary, progSource)

	// Build the program.
	cmd := exec.Command("go", cmdArgs...)
	cmd.Dir = tmpDir
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
		return nil, err
	}

	return run(filepath.Join(tmpDir, progBinary))
}