Using Multiple Perforce Depots with P4CONFIG
If your project contains directories that are stored in the different Perforce depots, you might need to switch between them. PhpStorm uses P4CONFIG to automatically switch to the respective depot as you use a Perforce-versioned directory.
P4CONFIG is an environment variable that contains the name of P4CONFIG file without a path. If a certain directory is associated with Perforce, PhpStorm seeks for P4CONFIG file in this directory and its parents; if the file is not found, it is sought in the bin directory of PhpStorm installation. When a P4CONFIG file is found, PhpStorm uses the settings contained therein, to connect to the respective Perforce depot.
A sample P4CONFG file might consist of such lines:
P4CLIENT=MyClient P4USER=MySelf P4PORT=ida:3456
To use multiple Perforce depots in a project, follow these general steps
Create a P4CONFIG file in each directory associated with Perforce.
Create environment variable P4CONFIG that contains file name without a path.