I have opened https://github.com/NixOS/nixpkgs/pull/421558
But I think this is not the way to go, at least not yet.

I don't want to imagine the merge issues with having made a change in 2000 packages, all of them near often-changing hash values and having them be only in staging but not master.

I think we should first have a staging cycle where the useFetchCargoVendor = true is made an actual NOOP (we filter it out from the attrs passed down to mkDerivation)
After that, we can do the same thing as my PR above, only targeting master directly and have no rebuilds

Any better ideas?

btw, you may want to collapse newlines for the

  cargoHash = "foo";

  useFetchCargoVendor = true;

  otherThing = 123;

case

I would like to revive some conversation around https://github.com/NixOS/nixpkgs/pull/387337

Currently the implementation creates a new subdirectory for each unique source that can be found in the lockfile

Here's an example of how the final directory layout might look like:

$ ls -A result/
.cargo  source-git-0  source-git-1  source-git-2  source-registry-0  Cargo.lock

$ cat result/.cargo/config.toml

[source._vendored-source-registry-0]
directory = "@vendor@/source-registry-0"

[source.crates-io]
replace-with = "_vendored-source-registry-0"

[source._vendored-source-git-0]
directory = "@vendor@/source-git-0"

[source._original-source-git-0]
git = "https://github.com/biomejs/biome"
rev = "2648fa4201be4afd26f44eca1a4e77aac0a67272"
replace-with = "_vendored-source-git-0"

[source._vendored-source-git-1]
directory = "@vendor@/source-git-1"

[source._original-source-git-1]
git = "https://github.com/lionel-/tower-lsp"
branch = "bugfix/patches"
replace-with = "_vendored-source-git-1"

[source._vendored-source-git-2]
directory = "@vendor@/source-git-2"

[source._original-source-git-2]
git = "https://github.com/r-lib/tree-sitter-r"
rev = "a0d3e3307489c3ca54da8c7b5b4e0c5f5fd6953a"
replace-with = "_vendored-source-git-2"