Currently when using --job with --easystack, --easystack gets passed along to job that in return try to process the easystack, causing parallel builds of the first item in the easystack file (which fail due to already existing locks).

how to reproduce

example.yml

software:
    GROMACS:
        toolchains:
            fosscuda-2019b:
                versions: '2020'

with eb --robot --job --experimental --easystack example.yml
causes

== FAILED: Installation ended unsuccessfully (build directory: /scratch/software_build/easybuild/build/GROMACS/2020/fosscuda-2019b): build failed (first 300 chars): Lock /software/.locks/_software_GROMACS_2020-fosscuda-2019b.lock already exists, aborting! (took 0 secs)

due to all parallel jobs trying to build the same easyconfig.

proposed solution

Do not pass --easystack to build jobs.