Brew报错：Version value must be a string； got a NilClass () (TypeError)

今天使用brew更新软件时，大概是因为太长时间没有更新了，出现了以下错误信息：

Updating Homebrew...
Traceback (most recent call last):
	11: from /usr/local/Homebrew/Library/Homebrew/brew.rb:23:in `<main>'
	10: from /usr/local/Homebrew/Library/Homebrew/brew.rb:23:in `require_relative'
	 9: from /usr/local/Homebrew/Library/Homebrew/global.rb:29:in `<top (required)>'
	 8: from /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	 7: from /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	 6: from /usr/local/Homebrew/Library/Homebrew/os.rb:3:in `<top (required)>'
	 5: from /usr/local/Homebrew/Library/Homebrew/os.rb:21:in `<module:OS>'
	 4: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:58:in `prerelease?'
	 3: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:24:in `version'
	 2: from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:24:in `new'
	 1: from /usr/local/Homebrew/Library/Homebrew/os/mac/version.rb:26:in `initialize'
/usr/local/Homebrew/Library/Homebrew/version.rb:368:in `initialize': Version value must be a string; got a NilClass () (TypeError)

在网上搜索以后，有的说是因为brew只支持正式发行版。/usr/local/Homebrew/Library/Homebrew/version.rb文件中第368行直接用@version = '10.14.1'给定一个版本号就可以了。但是我修改了以后，没有用。因为每次启动brew命令后/usr/local/Homebrew/Library/Homebrew/version.rb文件就会回复为原来的样子，错误依旧。
没有办法，那么就重置吧：brew update-reset。然后就OK了。
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原文链接：https://blog.csdn.net/mouse2018/article/details/114324847