M1 Mac更新Ruby至3.1.2后运行RSpec+Capybara测试报fork()未实现错误

API 探路者

2026-8-14

问题描述

近期通过rvm将Ruby版本从3.1.0更新至3.1.2，运行bundle exec rspec [filename_spec.rb]执行功能测试时出现以下错误：

NotImplementedError:
            fork() function is unimplemented on this machine
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/childprocess-4.1.0/lib/childprocess/unix/fork_exec_process.rb:20:in `fork'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/childprocess-4.1.0/lib/childprocess/unix/fork_exec_process.rb:20:in `launch_process'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/childprocess-4.1.0/lib/childprocess/abstract_process.rb:81:in `start'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/service_manager.rb:109:in `start_process'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/service_manager.rb:56:in `block in start'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/socket_lock.rb:41:in `locked'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/service_manager.rb:54:in `start'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/service.rb:84:in `launch'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/driver.rb:341:in `service_url'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/driver.rb:321:in `create_bridge'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/driver.rb:74:in `initialize'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/driver.rb:47:in `new'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver/common/driver.rb:47:in `for'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/selenium-webdriver-4.5.0/lib/selenium/webdriver.rb:89:in `for'
          # /Users/myuser/.rvm/gems/ruby-3.1.2/gems/capybara-3.36.0/lib/capybara/selenium/driver.rb:83:in `browser'
          # ./spec/rails_helper.rb:143:in `block (2 levels) in <top (required)>'

已尝试操作：卸载旧版本Ruby 3.1.0、重新运行bundle install、重新安装Ruby 3.1.2。

解决方案

该错误多出现于Apple Silicon（M1/M2）设备，核心是Ruby环境或childprocess gem对fork系统调用的兼容问题，可按以下步骤解决：

切换Ruby安装架构（Rosetta兼容模式）
如果是Apple Silicon设备，用Rosetta架构重新安装Ruby 3.1.2：
```
arch -x86_64 rvm uninstall 3.1.2
arch -x86_64 rvm install 3.1.2
arch -x86_64 rvm use 3.1.2 --default
bundle install
```
也可以直接右键终端→显示简介，勾选「使用Rosetta打开」，重启终端后重新执行测试。
升级childprocess gem
当前使用的childprocess 4.1.0对Apple Silicon支持不完善，升级到兼容版本：
在Gemfile中修改：
```
gem 'childprocess', '~> 4.2.0'
```
然后执行：
```
bundle update childprocess
```
强制childprocess使用posix_spawn替代fork
在spec/rails_helper.rb或spec/spec_helper.rb的开头（Capybara初始化前）添加配置：
```
require 'childprocess'
ChildProcess.posix_spawn = true
```
该配置会让childprocess使用posix_spawn替代fork，规避系统调用不兼容问题。

内容的提问来源于stack exchange，提问作者halpmeh