MacOS下PHP7.1升级到PHP7.4.15

最近写SDK的时候须要用到object类型提示符，PHPStorm智能提示说须要PHP7.2以上才能支持这种类型提示。
我一查我本机的PHP是7.1.30版本，因而考虑升级一下PHP版本。
首先要尝试使用以下命令进行升级：

brew update 
brew upgrade php@7.4

第一个遇到的报错以下所示：

git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow
This restriction has been made on GitHub's request because updating shallow
clones is an extremely expensive operation due to the tree layout and traffic of
Homebrew/homebrew-core and Homebrew/homebrew-cask. We don't do this for you
automatically to avoid repeatedly performing an expensive unshallow operation in
CI systems (which should instead be fixed to not use shallow clones). Sorry for
the inconvenience!

而后按照提醒执行"git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow"命令还会报错：

fatal: dumb http transport does not support shallow capabilities

由此怀疑homebrew-core的源可能由于一些不可抗力的缘由没法正常使用，从而致使fetch操做失败。能够考虑换成国内的源，编写shell以下所示：

# 切换到homebrew-core目录下
cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
# 设置homebrew源为国内的中科大镜像
git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-core.git
# 更新homebrew-core
git -C /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core fetch --unshallow

执行以后能够看到以下输出，而后就能够顺利执行brew update了。

remote: Enumerating objects: 539863, done.
remote: Counting objects: 100% (539826/539826), done.
remote: Compressing objects: 100% (194417/194417), done.
remote: Total 530481 (delta 341532), reused 521981 (delta 333211)
Receiving objects: 100% (530481/530481), 191.29 MiB | 9.18 MiB/s, done.
Resolving deltas: 100% (341532/341532), completed with 8120 local objects.

安装php7.4的方法很简单，能够使用源码下载编译的方法：

brew install --build-from-source php@7.4

能够看到大量输出，最后没有报错就能够完成php7.4的安装啦。

要让终端里面以前的PHP版本切换成功还须要在.bash_profile中设置环境变量，添加以下语句：

export PATH="/usr/local/opt/php@7.4/bin:$PATH"
export PATH="/usr/local/opt/php@7.4/sbin:$PATH"

最后执行source ~/.bash_profile命令完成生效操做。

为了确认是否真的生效，能够执行以下命令php -v
获得输出以下即为正确:

PHP 7.4.15 (cli) (built: Feb 21 2021 20:08:10) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v7.4.15, Copyright (c), by Zend Technologies

参考的资料以下：

1. homebrew国内源替换办法
2. php7.2升级到php7.4