error: no source URL specified for source./~https://github.com/jwilm/libfontconfig, need either registry or local-registry defined

[zimbatm]

How to reproduce:

$ git clone /~https://github.com/jwilm/alacritty.git
$ cd alacritty
$ mkdir .cargo
$ cargo vendor > .cargo/config # tweak accordingly
    Updating registry `/~https://github.com/rust-lang/crates.io-index`
    Updating git repository `/~https://github.com/jwilm/rust-fontconfig`
    Updating git repository `/~https://github.com/jwilm/libfontconfig`
 Downloading magenta v0.1.1
 Downloading regex v0.2.2
[snip]
$ rm -rf ~/.cargo
$ cargo build
error: no source URL specified for `source./~https://github.com/jwilm/libfontconfig`, need either `registry` or `local-registry` defined 

top-level Cargo.toml depends on ./fonts, which depends on /~https://github.com/jwilm/rust-fontconfig which depends on /~https://github.com/jwilm/libfontconfig

Both git dependencies are in vendor/servo-fontconfig and vendor/servo-fontconfig-sys respectively.
I suspect that the ~/.cargo/git cache is necessary to establish the map from the git repo to the package name?

[alexcrichton]

I think this may just be a feature that's implemented on beta but not on stable yet? I got the same failure on stable but it built correctly on beta.

[zimbatm]

That's good news! Do you know how long it will be until beta goes to stable?

[alexcrichton]

You can find that info here: https://forge.rust-lang.org/

Rust 1.22 stable will release on Thu Nov 23 2017.

[zimbatm]

@alexcrichton is it possible that your ~/.cargo wasn't flushed for you?

I am now using rust 1.22 1.22.1, cargo 1.22 0.22.0 and cargo-vendor 1.13 and getting the same issue.

This is part of the rust packaging effort in nix where every step is sandboxed. First we are getting all of the dependencies with cargo-vendor, store them into the /nix/store, then use that to compile the package. So both steps are separated and the ~/.cargo folder is lost in between.

[zimbatm]

The generated .cargo/config looks like this:

[source.crates-io]
replace-with = "vendored-sources"

[source."/~https://github.com/jwilm/libfontconfig"]
git = "/~https://github.com/jwilm/libfontconfig"
branch = "updated-2017-10-8"
replace-with = "vendored-sources"

[source."/~https://github.com/jwilm/rust-fontconfig"]
git = "/~https://github.com/jwilm/rust-fontconfig"
branch = "updated-2017-10-8"
replace-with = "vendored-sources"

[source.vendored-sources]
directory = "/nix/store/sj64n9740rb10c1444y1x01i63f6d565-alacritty-unstable-2017-11-20-vendor"

[alexcrichton]

Are you sure you're using an up-to-date Cargo? Cargo 1.22 doesn't actually exist...

[zimbatm]

Sorry, it should have been 0.22.0. I see that a new release have been published 10 hours ago, I will give it a try.

[zimbatm]

Would you be open to have a longer chat on rust packaging with potentially nix integration? It would be nice if I could nail the implementation to make it the best experience possible.

[alexcrichton]

Certainly yeah! It may be good roping in the rest of the Cargo team to the discussion as well (as it's likely highly related to build system integration)

[zimbatm]

Cool! What is the best way to organize that? I think on our end, @Mic92 would also be interested in participating in the discussion.

[Mic92]

In addition to basing builds on Cargo, we also now have a different promising approach
that increases also sharing of rust libraries between different projects and also allow to specify dependency on system libraries and non-cargo dependencies in a central place: NixOS/nixpkgs#31150
Support for git was also recently added there.
I would be still interested in sorting git support with cargo out to have a method that is up-to-date with all features cargo provides.

[alexcrichton]

It may be best to start out with a discussion on internals perhaps to see which Cargo team members are interested in participating?

[zimbatm]

Ok thanks. Cargo 0.23.0 fixes this ticket's issue.