Allow empty hash in derivations

follow up of https://github.com/NixOS/nix/pull/3544

This allows hash="" so that it can be used for debugging purposes. For
instance, this gives you an error message like:

  warning: found empty hash, assuming you wanted 'sha256:0000000000000000000000000000000000000000000000000000'
  hash mismatch in fixed-output derivation '/nix/store/asx6qw1r1xk6iak6y6jph4n58h4hdmbm-nix':
    wanted: sha256:0000000000000000000000000000000000000000000000000000
    got:    sha256:0fpfhipl9v1mfzw2ffmxiyyzqwlkvww22bh9wcy4qrfslb4jm429
This commit is contained in:
Matthew Bauer 2020-06-09 01:23:37 -05:00
parent d558fb98f6
commit 762273f1fd

View file

@ -719,7 +719,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
throw Error(format("multiple outputs are not supported in fixed-output derivations, at %1%") % posDrvName);
HashType ht = outputHashAlgo.empty() ? htUnknown : parseHashType(outputHashAlgo);
Hash h(*outputHash, ht);
Hash h;
if (outputHash->empty()) {
h = Hash(ht);
printError("warning: found empty hash, assuming you wanted '%s'", h.to_string());
} else
h = Hash(*outputHash, ht);
auto outPath = state.store->makeFixedOutputPath(ingestionMethod, h, drvName);
if (!jsonObject) drv.env["out"] = state.store->printStorePath(outPath);