This is documented Actions feature, so probably act should support it too.
I'm assuming this is exactly what's happening here then:
[phpunit/phpunit] ☁ git clone 'https://github.com/php-actions/composer' # ref=v2
[phpunit/phpunit] 🐳 docker build -t act-php-actions-composer-v2:latest /Users/martner/.cache/act/php-actions-composer@v2
[phpunit/phpunit] 🐳 docker run image=act-php-actions-composer-v2:latest entrypoint=[] cmd=[]
| Storing private key file for root
| # github.com:22 SSH-2.0-babeld-42834f78
| # gitlab.com:22 SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.8
| # bitbucket.org:22 SSH-2.0-conker_c123b90d72-dirty conker-3006
| getaddrinfo ${{: Name does not resolve
@powerman and @marartner can you give some examples of a workflow file where this is the case.
Pretty sure it's handled in #412 though
Most helpful comment
I'm assuming this is exactly what's happening here then: