Shallow realisations should go back to using regular drv paths #11897
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Ericson2314
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Feb 25, 2025
I refactored the way that input resolution works in `DerivationGoal`. To be honest, it is probably unclear to the reader whether this new way is better or worse. I suppose *intrinsic* motivation, I can say that - the more structured use of `inputGoal` (a local variable) is better than the shotgrun approach with `inputDrvOutputs` - A virtual `waiteeDone` was a hack, and now it's gone. However, the *real* motivation of this is not the above things, but that it is needed for my mammoth refactor fixing NixOS#11897 and NixOS#11928. It is nice that this step could come first, rather than making that refactor even bigger.
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This works especially nicely in conjunction with #11896
For deep realisations, using "derivation hashes modulo" helps save space. But for shallow ones, it achieves nothing, since those are already keyed on resolved derivations, which are always distinct modulo ways of producing inputs.
For shallow ones, we should just go back to using store paths, which will be simpler, and save implementations that only care about CA derivations from having to implement the cumbersome and ATerm-encumbered "derivation hash modulo" algorithm.
This is tantamount to reverting bab1cda for shallow realisations; note that that affects all derivations.
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