feat(tvix/nix-compat-derive): Add deriver for NixDeserialize r/8586

This adds a nix-compat-derive derive crate that implements a deriver
for NixDeserialize implementations. This is to reduce the amount of
code needed to implement deserialization for all the types used by
the Nix daemon protocol.

Change-Id: I484724b550e8a1d5e9adad9555d9dc1374ae95c2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12022
Autosubmit: Brian Olsen <me@griff.name>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.stderr
new file mode 100644
index 000000000000..5cc2f5974e4c
--- /dev/null
+++ b/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.stderr
@@ -0,0 +1,12 @@
+error[E0277]: the trait bound `Value: Default` is not satisfied
+ --> tests/ui/deserialize_missing_default.rs:6:10
+  |
+6 | #[derive(NixDeserialize)]
+  |          ^^^^^^^^^^^^^^ the trait `Default` is not implemented for `Value`
+  |
+  = note: this error originates in the derive macro `NixDeserialize` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider annotating `Value` with `#[derive(Default)]`
+  |
+4 + #[derive(Default)]
+5 | pub struct Value(String);
+  |