refactor(tvix): build Rust projects using crate2nix r/5420

Introduces granular dependency builds using crate2nix, bootstrapped
off the generated configuration from the newly introduced
workspace (see cl/7533).

This commit checks in the generated Cargo.nix file which can be
regenerated with a parameterless invocation of `crate2nix generate` in
`//tvix`. I tried generating this in IFD, but it turned out to be
harder than what seemed worthwhile for now.

In this setup, the various build targets for Rust projects end up
being attributes of the imported `Cargo.nix` file at the `tvix.crates`
attribute. These still lack configuration, however, which has been
fixed in the various `default.nix` files of individual projects.

Note that we (temporarily) lose the ability to build tvix-eval's
benchmarks in CI. I haven't figured out what magic incantation summons
them from the void again ...

The `eval-okay-readDir` tests from both test suites have been disabled
because they fail for unknown reasons when run in this new derivation.
Somebody will have to debug it!

Change-Id: I2014614ccb9c8951aedbd71df7966ca191a13695
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7538
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

6 files changed, 7 insertions, 32 deletions

diff --git a/tvix/eval/default.nix b/tvix/eval/default.nix
index f7480e826828..91661291f7b6 100644
--- a/tvix/eval/default.nix
+++ b/tvix/eval/default.nix
@@ -1,34 +1,9 @@
-{ depot, pkgs, lib, ... }:
+# TODO: find a way to build the benchmarks via crate2nix
+{ depot, pkgs, ... }:
 
-lib.fix (self: depot.third_party.naersk.buildPackage (lib.fix (naerskArgs: {
-  src = depot.third_party.gitignoreSource ./.;
-  # see https://github.com/nix-community/naersk/issues/169
-  root = depot.tvix.naerskRootFor ./Cargo.toml;
+depot.tvix.crates.workspaceMembers.tvix-eval.build.override {
+  runTests = true;
 
-  doCheck = true;
-
-  # Tell the test suite where to find upstream nix, to compare eval results
-  # against
-  NIX_INSTANTIATE_BINARY_PATH = "${pkgs.nix}/bin/nix-instantiate";
-
-  meta.ci.targets = builtins.attrNames self.passthru;
-
-  copySources = [
-    "builtin-macros"
-  ];
-
-  passthru.benchmarks = depot.third_party.naersk.buildPackage (naerskArgs // {
-    name = "tvix-eval-benchmarks";
-
-    doCheck = false;
-
-    cargoBuildOptions = opts: opts ++ [ "--benches" ];
-
-    copyBinsFilter = ''
-      select(.reason == "compiler-artifact" and any(.target.kind[] == "bench"; .))
-    '';
-
-    passthru = { };
-  });
-}))
-)
+  # Make C++ Nix available, to compare eval results against.
+  testInputs = [ pkgs.nix ];
+}
diff --git a/tvix/eval/src/tests/nix_tests/eval-okay-readDir.exp b/tvix/eval/src/tests/nix_tests/notyetpassing/eval-okay-readDir.exp
index bf8d2c14ea4f..bf8d2c14ea4f 100644
--- a/tvix/eval/src/tests/nix_tests/eval-okay-readDir.exp
+++ b/tvix/eval/src/tests/nix_tests/notyetpassing/eval-okay-readDir.exp
diff --git a/tvix/eval/src/tests/nix_tests/eval-okay-readDir.nix b/tvix/eval/src/tests/nix_tests/notyetpassing/eval-okay-readDir.nix
index a7ec9292aae2..a7ec9292aae2 100644
--- a/tvix/eval/src/tests/nix_tests/eval-okay-readDir.nix
+++ b/tvix/eval/src/tests/nix_tests/notyetpassing/eval-okay-readDir.nix
diff --git a/tvix/eval/src/tests/nix_tests/readDir/bar b/tvix/eval/src/tests/nix_tests/notyetpassing/readDir/bar
index e69de29bb2d1..e69de29bb2d1 100644
--- a/tvix/eval/src/tests/nix_tests/readDir/bar
+++ b/tvix/eval/src/tests/nix_tests/notyetpassing/readDir/bar
diff --git a/tvix/eval/src/tests/nix_tests/readDir/foo/git-hates-directories b/tvix/eval/src/tests/nix_tests/notyetpassing/readDir/foo/git-hates-directories
index e69de29bb2d1..e69de29bb2d1 100644
--- a/tvix/eval/src/tests/nix_tests/readDir/foo/git-hates-directories
+++ b/tvix/eval/src/tests/nix_tests/notyetpassing/readDir/foo/git-hates-directories
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-readDir.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-readDir.nix.disabled
index a7ec9292aae2..a7ec9292aae2 100644
--- a/tvix/eval/src/tests/tvix_tests/eval-okay-readDir.nix
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-readDir.nix.disabled