discussion: bzlmod, fineGrainedHashExternalRepos and external query #265
Description
In a bzlmod setup, querying //external:all-targets doesn't make much sense anymore because we will miss everything managed by bzlmod, and there is no "repo-generation" targets that we use to compute "coarse grained" hash.
I think we might need to rethink the whole idea of fineGrainedHashExternalRepos. Do we really need it? Can we always do "fine-grained" hash generation?
I think fineGrainedHashExternalRepos serves two purposes today. For cquery, it is a filter to apply source hashing; and for query, besides the filter functionality, it is also a source where we query things. BTW, I think "coarse grained" hashing for query has long been broken ever since we stopped querying //external:all-targets.
It is probably straight forward to modify cquery path to always do "fine grained" hashing, but not for query unless we switch to querying deps(//...:all-targets) as well, which I'm not sure why we didn't do it in the first place.
I might be understanding things totally wrong as I'm not familiar with the code base and design. Please help me understand @tinder-maxwellelliott . Thank you.