Deploy step fails with ruby error `system': wrong first argument (ArgumentError)

The error happens with a script provider.
Here’s the yaml:
deploy:

  • provider: script
    skip_cleanup: true
    script:
    • echo ‘about to call publish-edge**************’
    • pwd
    • ./scripts/publish-edge.sh
      on:
      all_branches: true

Here’s the resulting error:
1.67s$ rvm $(travis_internal_ruby) --fuzzy do ruby -S gem install dpl

Fetching dpl-1.10.11.gem

Successfully installed dpl-1.10.11

Parsing documentation for dpl-1.10.11

Installing ri documentation for dpl-1.10.11

Done installing documentation for dpl after 0 seconds

1 gem installed

dpl.1

Installing deploy dependencies

Fetching dpl-script-1.10.11.gem

Successfully installed dpl-script-1.10.11

Parsing documentation for dpl-script-1.10.11

Installing ri documentation for dpl-script-1.10.11

Done installing documentation for dpl-script after 0 seconds

1 gem installed

dpl.2

Preparing deploy

dpl.3

Deploying application

/home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/cli.rb:54:in `system': wrong first argument (ArgumentError)

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/cli.rb:54:in `shell'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-script-1.10.11/lib/dpl/provider/script.rb:19:in `push_app'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/provider.rb:199:in `block in deploy'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/cli.rb:41:in `fold'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/provider.rb:199:in `deploy'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/cli.rb:32:in `run'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/lib/dpl/cli.rb:7:in `run'

from /home/travis/.rvm/gems/ruby-2.4.1/gems/dpl-1.10.11/bin/dpl:5:in `<top (required)>'

from /home/travis/.rvm/gems/ruby-2.4.1/bin/dpl:23:in `load'

from /home/travis/.rvm/gems/ruby-2.4.1/bin/dpl:23:in `<main>'

failed to deploy
Imprint