"cache key: blob not found" error after upgrading from buildkit 12.1 to 13.0

[gibsondan]

This morning a user reported that our github action started failing with the following error in a step that uses the docker/build-push-action@v4 action :

Dockerfile:7
--------------------
   6 |     COPY *dagster_cloud_pre_install.sh *setup.py *requirements.txt /
   7 | >>> RUN if [ -f "dagster_cloud_pre_install.sh" ]; then \
   8 | >>>         ./dagster_cloud_pre_install.sh; \
   9 | >>>     fi
  10 |     
--------------------
ERROR: failed to solve: failed to compute cache key: blob sha256:043e7f3dd05ab4bea31533694054d95fdc672fa089066248f176a60cb051493c not found
Error: buildx failed with: ERROR: failed to solve: failed to compute cache key: blob sha256:043e7f3dd05ab4bea31533694054d95fdc672fa089066248f176a60cb051493c not found

The only significant change they noticed between the last time it succeeded and the first time that it failed was that the Buildkit version upgraded from v0.12.1 to v0.13.0.

The symptoms here look identical to docker/buildx#681 - I see that KevinMind reported a similar problem with the same version bump this morning.

Unfortunately I do not have a way to reliably reproduce this problem yet, but I figured with two independent reports on the same version upgrade it was still worth filing an issue.

[tonistiigi]

If anyone has a way to reproduce this, then let us know to aide us debugging this issue.