Pass a specific PHP version to subscripts in a CLI call

pass-php-version-to-subscripts-in-cli-calls.md

Pass a specific PHP version to subscripts in a CLI call

Origin

Using the PPA ondrej/php it is possible to run multiple PHP version on one system.

All single versions are useable on the CLI, e.g. php7.4 --version. The command php will point to the default version.

Problem

Now whenever a PHP script is executed by CLI and triggers another PHP script itself, the default version is used.

Example: Your default version is 7.2, you run Composer with 7.4, binaries triggered in hooks still use 7.2.

composer.json

{
    "name": "acme/php-cli-switch",
    "description": "Test passing different PHP versions to CLI",
    "license": "GPL-2.0-or-later",
    "scripts": {
        "php-version": "php --version"
    }
}

Tests

php --version
> PHP 7.2.34

php /usr/local/bin/composer php-version
> PHP 7.2.34

php7.4 --version
> PHP 7.4.22

php7.4 /usr/local/bin/composer php-version
> PHP 7.2.34

Solutions

Change permanently

Change the default version using update-alternatives.

sudo update-alternatives --set php /usr/bin/php7.4
sudo update-alternatives --set phar /usr/bin/phar7.4
sudo update-alternatives --set phar.phar /usr/bin/phar.phar7.4

Repeat the command whenever the version needs to be changed again.

Override temporarily

If it is not allowed to change the default version on the system, then you may override the $PATH environment variable change the default version.

The important part here is to create a symlink first, which points to the desired version and is named php exactly. This is due to the fact, that calls for php are passed to /usr/bin/env, which looks for an executable named php in the current $PATH. It does not work with aliases, shell functions or any other names.

mkdir -p ~/.php/versions/7.4/bin/
ln -s /usr/bin/php7.4 ~/.php/versions/7.4/bin/php

Now pass the version directory as environment variable.

Tests

php --version
> PHP 7.2.34

PATH="/home/$USER/.php/versions/7.4/bin:$PATH" php --version
> PHP 7.4.22

PATH="/home/$USER/.php/versions/7.4/bin:$PATH" php /usr/local/bin/composer php-version
> PHP 7.4.22

Since this is a unpleasantly long command, you may create an alias for it.

.bash_aliases

alias php-cli-7.4='PATH="/home/$USER/.php/versions/7.4/bin:$PATH" php'

Tests

php-cli-7.4 --version
> PHP 7.4.22

php-cli-7.4 /usr/local/bin/composer php-version
> PHP 7.4.22

Follow up: Pick up PHP versions from a .php-version file and pass the selected version to subscripts automatically → https://github.com/webit-de/php-version-pickup