如何升级PHP至7.3+以解决Symfony项目Composer依赖问题

Hey there, I’ve dealt with this exact scenario on Ubuntu 18.04 before—since the default system repositories only ship with PHP 7.2, you’ll need to use a trusted third-party PPA to get newer PHP versions. Here’s a step-by-step guide:

1. 添加PHP官方维护的PPA #

The ondrej/php PPA is the go-to source for updated PHP packages on Ubuntu, maintained by the PHP community. Run these commands to add it and refresh your package list:

sudo add-apt-repository ppa:ondrej/php
sudo apt update

2. 安装PHP 7.3（或更高版本） #

Install PHP 7.3 along with common extensions that Symfony projects typically require. Adjust the extensions based on your project’s specific needs:

sudo apt install php7.3 php7.3-cli php7.3-fpm php7.3-mysql php7.3-xml php7.3-curl php7.3-gd php7.3-mbstring

If you need a newer version (like 7.4 or 8.0), just replace 7.3 with your target version number in the command above.

3. 切换系统默认PHP版本 #

Ubuntu will keep the old PHP 7.2 installed by default, so you need to set PHP 7.3 as the default for CLI:

sudo update-alternatives --set php /usr/bin/php7.3

Verify the change by running:

php -v

You should see output showing PHP 7.3.x instead of 7.2.24.

4. 适配Web服务器（如果需要） #

If your Symfony project runs on a web server like Apache or Nginx, you’ll need to update the server to use the new PHP version:

• For Apache:

  sudo a2dismod php7.2
  sudo a2enmod php7.3
  sudo systemctl restart apache2
  

• For Nginx:
  Edit your site’s Nginx configuration file (usually located in /etc/nginx/sites-available/), find the fastcgi_pass line, and update it to point to PHP 7.3’s socket:

  fastcgi_pass unix:/run/php/php7.3-fpm.sock;
  

  Then restart Nginx:

  sudo systemctl restart nginx
  

5. 重新运行Composer #

Once PHP 7.3 is set up, go back to your Symfony project directory and run:

composer install

This should resolve the version conflict with ocramius/package-versions and complete the dependency installation.

内容的提问来源于stack exchange，提问作者malongoDB