buildRustPackage fails for projects with no dependencies in Cargo.toml

[dermetfan]

Issue description

buildRustPackage fails for projects that declare no dependencies in Cargo.toml.

see #22735

Steps to reproduce

Try building this example project:

❯ nix-build release.nix -A build --arg nixpkgs '<nixpkgs>' --argstr system x86_64-linux
these derivations will be built:
  /nix/store/dw177b3in0rmfsx237jlzqimbjmcxrpk-ill-fetch.drv
  /nix/store/c4klqbmccg501naxznl48w24hpazgdc1-ill.drv
building path(s) ‘/nix/store/dy1dywfq2mh035z4v0phmx0kg7p066cw-ill-fetch’
unpacking sources
unpacking source archive /nix/store/q6b7iql14yafz8j2hqq3x4g6fzpdamxy-ill
source root is ill
installing
Fetching /tmp/nix-build-ill-fetch.drv-0/ill to /nix/store/dy1dywfq2mh035z4v0phmx0kg7p066cw-ill-fetch
Using rust registry from /nix/store/ri6jzyj02dw56zr5bk9yvaci6zr4g7vw-rustRegistry-2017-01-27-6a73a15
warning: custom registry support via the `registry.index` configuration is being removed, this functionality will not work in the future
mv: missing destination file operand after '/nix/store/dy1dywfq2mh035z4v0phmx0kg7p066cw-ill-fetch/registry/cache/HASH'
Try 'mv --help' for more information.
builder for ‘/nix/store/dw177b3in0rmfsx237jlzqimbjmcxrpk-ill-fetch.drv’ failed with exit code 1
cannot build derivation ‘/nix/store/c4klqbmccg501naxznl48w24hpazgdc1-ill.drv’: 1 dependencies couldn't be built
error: build of ‘/nix/store/c4klqbmccg501naxznl48w24hpazgdc1-ill.drv’ failed

Technical details

• System: 17.03pre100522.01fef3f (Gorilla)
• Nix version:nix-env (Nix) 1.11.6
• Nixpkgs version: 17.03pre100522.01fef3f

[mmahut]

Are there any updates to this issue, please?

[Deluvi]

I have just tested on the sample hello world that Cargo provides with cargo init, buildRustPackage was able to perform the build just fine. This has probably been fixed at some point.

[stale]

Thank you for your contributions.
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[liff]

I think this still happens. The elfcat package fails to build (from Hydra):

unpacking sources
unpacking source archive /nix/store/y61ycffrys6xjvgfhhhi8s2fidaz43ga-source
source root is source
patching sources
configuring
no configure script, doing nothing
building
There is no dependency to vendor in this project.
Traceback (most recent call last):
  File "/nix/store/9cqhrbp7v53q98ly12gzpsqck1cxzqvp-cargo-vendor-normalise/bin/.cargo-vendor-normalise-wrapped", line 42, in <module>
    main()
  File "/nix/store/9cqhrbp7v53q98ly12gzpsqck1cxzqvp-cargo-vendor-normalise/bin/.cargo-vendor-normalise-wrapped", line 17, in main
    assert list(data.keys()) == ["source"]
AssertionError

It has cargoSha256 = null so I imagine this was working earlier and then regressed.

[liff]

Bisected to dc93e10. Looks like the way cargo vendor works changed between 1.58 and 1.59.

❯ rustup run 1.58.1 cargo vendor
To use vendored sources, add this to your .cargo/config.toml for this project:

[source.vendored-sources]
directory = "vendor"
❯ rustup run 1.59.0 cargo vendor
There is no dependency to vendor in this project.

The cargo-vendor-normalise script always expects the first kind of output.