I noticed you start to find every operating system quirk ever when you start writing Dockerfiles. I've run into so many strange things just converting a simple predictable shell script into a Dockerfile.
I've been using Dockerfiles extensively for years and I'm yet to find anything that fits the definition of a OS quirk.
The quirkiest thing I've noticed in Dockerfiles is the ADD vs COPY thing.
> I've run into so many strange things just converting a simple predictable shell script into a Dockerfile.
What exactly are you trying to do setting up a Dockerfile that requires a full blown shell script?
A Dockerfile should have little more beyond updating/installing system packages with a package manager, and copying files into the container image. First you run a build to get your artifacts ready for packaging, and afterwards you package those artifacts by running your Dockerfile.
The mistake many do is seeing dockerfiles as a 1:1 mapping of a shell script with RUN prefixed on every line. It’s not, you should only split a run if you have a good reason to add a new COPY in between for layer caching reasons or switching user.
With the --bind options from buildkit you can ensure the apt cache does not get layered and you can mount any big temporary files needed from host instead of copying them first.