Generating files in k8-fastbuild vs. k8-opt-exec-ST-XXX

[Michael Allwright]

I am confused about the output directories k8-fastbuild and k8-opt-exec-ST-XXX, specifically, why some of my assets seem to be outputted in one and not the other.

For example, if I use write_file or genrule to generate a file and pass it to this rule as em_config and then check its path in the implementation of that rule, it reports a path under k8-fastbuild. However, if I search for the file inside of the sandbox, I find that the path given is almost correct except instead of being under k8-fastbuild, it is under k8-opt-exec-ST-13d3ddad9198.

Is File.path reporting the incorrect path to the file or have I misunderstood something?