ERROR: invalid user index: -1

[pjonsson]

Version 8 of this action fails to build my Dockerfile for some reason, and the error message is a non-descriptive ERROR: invalid user index: -1. The line in the Dockerfile that fails is COPY --from=builder --link --chown=ubuntu:ubuntu /app /app, and the ubuntu user/group exists in the image.

Here's the end of the log from https://github.com/opendatacube/datacube-docker/actions/runs/12019463956/job/33506297098 running on the main branch:

#22 160.7  + xarray==2024.10.0
#22 160.7  + yarl==1.18.0
#22 160.7  + zict==3.0.0
#22 DONE 162.0s

#23 copy /build/*.txt /conf/
#23 DONE 0.0s

#24 copy /app /app
#24 ERROR: invalid user index: -1
------
 > copy /app /app:
------
ERROR: failed to solve: invalid user index: -1
+ logout_from_registry
+ echo -e '\n[Action Step] Log out from registry...'
+ docker logout ''

[Action Step] Log out from registry...
Removing login credentials for https://index.docker.io/v1/

In comparison, here's the log for a different job (https://github.com/opendatacube/datacube-docker/actions/runs/12006991028/job/33466657469) of the same commit on the main branch:

#17 169.8  + xarray==2024.10.0
#17 169.8  + yarl==1.18.0
#17 169.8  + zict==3.0.0
#17 DONE 171.1s

#18 [index stage-1 4/8] COPY --from=builder --link --chown=ubuntu:ubuntu /app /app
#18 DONE 3.6s

#19 [index stage-1 5/8] COPY --from=builder --link /build/*.txt /conf/
#19 DONE 0.0s

#20 [index stage-1 6/8] COPY --link ./assets /code
...

The job that doesn't fail runs on a regular Github CI runner using ubuntu-latest using the Docker packages Github provides by default.

I don't know why the buildx this action uses both lowercases the COPY and omits the --from=builder --link --chown=ubuntu:ubuntu in the output.