Why isn't the convention in nixpkgs that `hash` is overridable too (along with version) so package overrides would actually be useful?

Development
9

I just tried to do this ~1h ago, and I had to use 3 layers of nested overrideAttrs, and temporarily set outputHashAlgo in order to get the right outputHash from the error message.

I have not tested this, but I suspect using the cargoHash from finalAttrs would be able to fix this.

--- a/pkgs/build-support/rust/build-rust-package/default.nix
+++ b/pkgs/build-support/rust/build-rust-package/default.nix
@@ -127,7 +127,7 @@ lib.extendMkDerivation {
                 ;
               name = cargoDepsName;
               patches = cargoPatches;
-              hash = args.cargoHash;
+              hash = finalAttrs.cargoHash;
             }
             // depsExtraArgs
           );

It would also allow things like cargoPatches to be overrideAttrsed, where in the original change I had to specify patches twice.

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