silently failing to download and stage source release file

[eedwards-sk]

with concourse 4.0.0:

I have a pipeline which grabs a github release archive:

- name: homebrew
  type: github-release
  check_every: 12h
  source:
    owner: Homebrew
    repository: brew

and

    - get: homebrew
      params:
        include_source_tarball: true

The pipeline was working fine, then I put my computer to sleep with the stack 'stopped', then resumed my pc and woke the stack back up. The pipeline ran again as expected, and showed a valid version for the homebrew resource.

However, when it gets to the step in the pipeline where it uses the file, there's no .tar.gz file to be found!

+ cd /opt/concourse/local/worker/volumes/live/7df5d723-4cb4-4239-7b73-d3c6857ebe6c/volume/homebrew
+ ls -la
total 0
drwxr-xr-x  2 eedwards  staff   64 Aug 16 10:41 .
drwxr-xr-x  6 root      staff  192 Aug 17 09:40 ..

So for whatever reason the check container is reporting success, and concourse is acting like it pulled and staged the resource correctly, but the binary file is missing!

Also, a fly check-resource succeeds, but the file is still missing!