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

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>

tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.rs

@@ -0,0 +1,10 @@
+use nix_compat_derive::NixDeserialize;
+
+pub struct BadType;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    version: BadType,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.stderr

@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `BadType: NixDeserialize` is not satisfied
+ --> tests/ui/deserialize_bad_type.rs:7:14
+  |
+7 |     version: BadType,
+  |              ^^^^^^^ the trait `NixDeserialize` is not implemented for `BadType`
+  |
+  = help: the following other types implement trait `NixDeserialize`:
+            BTreeMap<K, V>
+            String
+            Test
+            Vec<T>
+            bool
+            bytes::bytes::Bytes
+            i64
+            u64
+            usize
+note: required by a bound in `try_read_value`
+ --> $WORKSPACE/nix-compat/src/nix_daemon/de/mod.rs
+  |
+  |     fn try_read_value<V: NixDeserialize>(
+  |                          ^^^^^^^^^^^^^^ required by this bound in `NixRead::try_read_value`

tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.rs

@@ -0,0 +1,13 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub enum Test {
+    #[nix(version = "..=10")]
+    Old,
+    #[nix(version = "15..=17")]
+    Legacy,
+    #[nix(version = "50..")]
+    NewWay,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.stderr

@@ -0,0 +1,8 @@
+error[E0004]: non-exhaustive patterns: `11_u8..=14_u8` and `18_u8..=49_u8` not covered
+ --> tests/ui/deserialize_enum_non_exaustive.rs:3:10
+  |
+3 | #[derive(NixDeserialize)]
+  |          ^^^^^^^^^^^^^^ patterns `11_u8..=14_u8` and `18_u8..=49_u8` not covered
+  |
+  = note: the matched value is of type `u8`
+  = note: this error originates in the derive macro `NixDeserialize` (in Nightly builds, run with -Z macro-backtrace for more info)

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.rs

@@ -0,0 +1,7 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+#[nix(from = "u64")]
+pub struct Test;
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.stderr

@@ -0,0 +1,5 @@
+error[E0277]: the trait bound `Test: From<u64>` is not satisfied
+ --> tests/ui/deserialize_from_missing.rs:4:14
+  |
+4 | #[nix(from = "u64")]
+  |              ^^^^^ the trait `From<u64>` is not implemented for `Test`

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.rs

@@ -0,0 +1,20 @@
+use std::str::FromStr;
+
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+#[nix(from_str)]
+pub struct Test;
+
+impl FromStr for Test {
+    type Err = ();
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s == "test" {
+            Ok(Test)
+        } else {
+            Err(())
+        }
+    }
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.stderr

@@ -0,0 +1,13 @@
+error[E0277]: `()` doesn't implement `std::fmt::Display`
+ --> tests/ui/deserialize_from_str_error_not_display.rs:6:7
+  |
+6 | #[nix(from_str)]
+  |       ^^^^^^^^ `()` cannot be formatted with the default formatter
+  |
+  = help: the trait `std::fmt::Display` is not implemented for `()`
+  = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
+note: required by a bound in `invalid_data`
+ --> $WORKSPACE/nix-compat/src/nix_daemon/de/mod.rs
+  |
+  |     fn invalid_data<T: fmt::Display>(msg: T) -> Self {
+  |                        ^^^^^^^^^^^^ required by this bound in `Error::invalid_data`

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.rs

@@ -0,0 +1,7 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+#[nix(from_str)]
+pub struct Test;
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.stderr

@@ -0,0 +1,16 @@
+error[E0277]: the trait bound `Test: FromStr` is not satisfied
+ --> tests/ui/deserialize_from_str_missing.rs:4:7
+  |
+4 | #[nix(from_str)]
+  |       ^^^^^^^^ the trait `FromStr` is not implemented for `Test`
+  |
+  = help: the following other types implement trait `FromStr`:
+            IpAddr
+            Ipv4Addr
+            Ipv6Addr
+            NonZero<i128>
+            NonZero<i16>
+            NonZero<i32>
+            NonZero<i64>
+            NonZero<i8>
+          and $N others

tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.rs

@@ -0,0 +1,12 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Value(String);
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(version = "20..")]
+    version: Value,
+}
+
+fn main() {}

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);
+  |

tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.rs

@@ -0,0 +1,12 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Value(String);
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(version = "20..", default = "Value::make_default")]
+    version: Value,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.stderr

@@ -0,0 +1,8 @@
+error[E0599]: no function or associated item named `make_default` found for struct `Value` in the current scope
+ --> tests/ui/deserialize_missing_default_path.rs:8:39
+  |
+4 | pub struct Value(String);
+  | ---------------- function or associated item `make_default` not found for this struct
+...
+8 |     #[nix(version = "20..", default = "Value::make_default")]
+  |                                       ^^^^^^^^^^^^^^^^^^^^^ function or associated item not found in `Value`

tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.rs

@@ -0,0 +1,15 @@
+use nix_compat_derive::nix_deserialize_remote;
+
+pub struct Value(String);
+impl From<String> for Value {
+    fn from(s: String) -> Value {
+        Value(s)
+    }
+}
+
+nix_deserialize_remote!(
+    #[nix()]
+    Value
+);
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.stderr

@@ -0,0 +1,5 @@
+error: Missing from_str, from or try_from attribute
+  --> tests/ui/deserialize_remote_missing_attr.rs:10:25
+   |
+10 | nix_deserialize_remote!(#[nix()] Value);
+   |                         ^^^^^^^^^^^^^^

tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.rs

@@ -0,0 +1,19 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+#[nix(try_from = "u64")]
+pub struct Test;
+
+impl TryFrom<u64> for Test {
+    type Error = ();
+
+    fn try_from(value: u64) -> Result<Test, Self::Error> {
+        if value == 42 {
+            Ok(Test)
+        } else {
+            Err(())
+        }
+    }
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.stderr

@@ -0,0 +1,13 @@
+error[E0277]: `()` doesn't implement `std::fmt::Display`
+ --> tests/ui/deserialize_try_from_error_not_display.rs:4:18
+  |
+4 | #[nix(try_from = "u64")]
+  |                  ^^^^^ `()` cannot be formatted with the default formatter
+  |
+  = help: the trait `std::fmt::Display` is not implemented for `()`
+  = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
+note: required by a bound in `invalid_data`
+ --> $WORKSPACE/nix-compat/src/nix_daemon/de/mod.rs
+  |
+  |     fn invalid_data<T: fmt::Display>(msg: T) -> Self {
+  |                        ^^^^^^^^^^^^ required by this bound in `Error::invalid_data`

tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.rs

@@ -0,0 +1,7 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+#[nix(try_from = "u64")]
+pub struct Test;
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.stderr

@@ -0,0 +1,8 @@
+error[E0277]: the trait bound `Test: From<u64>` is not satisfied
+ --> tests/ui/deserialize_try_from_missing.rs:4:18
+  |
+4 | #[nix(try_from = "u64")]
+  |                  ^^^^^ the trait `From<u64>` is not implemented for `Test`, which is required by `Test: TryFrom<u64>`
+  |
+  = note: required for `u64` to implement `Into<Test>`
+  = note: required for `Test` to implement `TryFrom<u64>`

tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.rs

@@ -0,0 +1,9 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(default = 12)]
+    version: u8,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.stderr

@@ -0,0 +1,5 @@
+error: expected nix attribute default to be string
+ --> tests/ui/parse_bad_default.rs:5:21
+  |
+5 |     #[nix(default = 12)]
+  |                     ^^

tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.rs

@@ -0,0 +1,9 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(default = "12")]
+    version: u8,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.stderr

@@ -0,0 +1,5 @@
+error: expected identifier
+ --> tests/ui/parse_bad_default_path.rs:5:21
+  |
+5 |     #[nix(default = "12")]
+  |                     ^^^^

tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.rs

@@ -0,0 +1,9 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix]
+    version: u8,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.stderr

@@ -0,0 +1,5 @@
+error: expected attribute arguments in parentheses: #[nix(...)]
+ --> tests/ui/parse_bad_nix.rs:5:7
+  |
+5 |     #[nix]
+  |       ^^^

tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.rs

@@ -0,0 +1,9 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(version = 12)]
+    version: u8,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.stderr

@@ -0,0 +1,5 @@
+error: expected nix attribute version to be string
+ --> tests/ui/parse_bad_version.rs:5:21
+  |
+5 |     #[nix(version = 12)]
+  |                     ^^

tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.rs

@@ -0,0 +1,9 @@
+use nix_compat_derive::NixDeserialize;
+
+#[derive(NixDeserialize)]
+pub struct Test {
+    #[nix(version)]
+    version: u8,
+}
+
+fn main() {}

tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.stderr

@@ -0,0 +1,5 @@
+error: expected `=`
+ --> tests/ui/parse_mising_version.rs:5:18
+  |
+5 |     #[nix(version)]
+  |                  ^