When a project is launched through a pass/fail chain, the system
applies environment variables from the calling project. The called
project sets up variables from the calling project's environment and
its own environment in the following order:
- Called project server environment.
- Calling project's variables, in a set, with "BF_" variable
names changed to "BF_CALLER_".
- Called project server environment (applied a second time in case
it was modified by the caller's variables).
- Called project environment.
- Step environments (if specified) as they are run.