feat(tvix): add CI targets for checking crate features powerset r/8211

Closes: https://b.tvl.fyi/issues/401

With this change all crate features (and their combinations) will be built and
tested in CI.

From now on, when adding/removing a Cargo feature for a crate,
you will want to add it to the features power set that gets tested in CI.
For each crate there's a default.nix with a `mkFeaturePowerset` invocation,
modify the list to include/remove the feature.
Note that you don't want to add "collection" features,
such as `fs` for tvix-[ca]store or `default`.

Change-Id: I966dde1413d057770787da3296cce9c1924570e0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11717
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

1 files changed, 5 insertions, 0 deletions

diff --git a/tvix/README.md b/tvix/README.md
index fb536bc229c0..7f3fcc061597 100644
--- a/tvix/README.md
+++ b/tvix/README.md
@@ -104,6 +104,11 @@ Rust projects under `//tvix`, be sure to run
 `mg run //tools:crate2nix-generate` in `//tvix` itself and commit the changes
 to the generated `Cargo.nix` file. This only applies to the full TVL checkout.
 
+When adding/removing a Cargo feature for a crate, you will want to add it to the
+features power set that gets tested in CI. For each crate there's a default.nix with a
+`mkFeaturePowerset` invocation, modify the list to include/remove the feature.
+Note that you don't want to add "collection" features, such as `fs` for tvix-[ca]store or `default`.
+
 ## License structure
 
 All code implemented for Tvix is licensed under the GPL-3.0, with the