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-rw-r--r--tvix/Cargo.lock44
-rw-r--r--tvix/Cargo.nix172
-rw-r--r--tvix/Cargo.toml2
-rw-r--r--tvix/nix-compat-derive-tests/Cargo.toml27
-rw-r--r--tvix/nix-compat-derive-tests/default.nix5
-rw-r--r--tvix/nix-compat-derive-tests/tests/read_derive.rs417
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui.rs6
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.rs10
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.stderr21
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.rs13
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.stderr8
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.rs7
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.rs20
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.stderr13
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.rs7
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.stderr16
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.rs12
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.stderr12
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.rs12
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.stderr8
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.rs15
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.rs19
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.stderr13
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.rs7
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.stderr8
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.rs9
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.rs9
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.rs9
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.rs9
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.stderr5
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.rs9
-rw-r--r--tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.stderr5
-rw-r--r--tvix/nix-compat-derive/Cargo.toml32
-rw-r--r--tvix/nix-compat-derive/default.nix5
-rw-r--r--tvix/nix-compat-derive/src/de.rs272
-rw-r--r--tvix/nix-compat-derive/src/internal/attrs.rs358
-rw-r--r--tvix/nix-compat-derive/src/internal/ctx.rs50
-rw-r--r--tvix/nix-compat-derive/src/internal/inputs.rs110
-rw-r--r--tvix/nix-compat-derive/src/internal/mod.rs183
-rw-r--r--tvix/nix-compat-derive/src/internal/symbol.rs32
-rw-r--r--tvix/nix-compat-derive/src/lib.rs348
-rw-r--r--tvix/nix-compat/Cargo.toml8
-rw-r--r--tvix/nix-compat/src/nix_daemon/protocol_version.rs7
48 files changed, 2376 insertions, 3 deletions
diff --git a/tvix/Cargo.lock b/tvix/Cargo.lock
index 11014d2011be..7bf6594759dd 100644
--- a/tvix/Cargo.lock
+++ b/tvix/Cargo.lock
@@ -2342,6 +2342,7 @@ dependencies = [
  "hex-literal",
  "lazy_static",
  "mimalloc",
+ "nix-compat-derive",
  "nom",
  "num-traits",
  "pin-project-lite",
@@ -2359,6 +2360,35 @@ dependencies = [
 ]
 
 [[package]]
+name = "nix-compat-derive"
+version = "0.1.0"
+dependencies = [
+ "hex-literal",
+ "nix-compat",
+ "pretty_assertions",
+ "proc-macro2",
+ "quote",
+ "rstest",
+ "syn 2.0.72",
+ "tokio",
+ "tokio-test",
+]
+
+[[package]]
+name = "nix-compat-derive-tests"
+version = "0.1.0"
+dependencies = [
+ "hex-literal",
+ "nix-compat",
+ "nix-compat-derive",
+ "pretty_assertions",
+ "rstest",
+ "tokio",
+ "tokio-test",
+ "trybuild",
+]
+
+[[package]]
 name = "nohash-hasher"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -4709,6 +4739,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
 [[package]]
+name = "trybuild"
+version = "1.0.99"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "207aa50d36c4be8d8c6ea829478be44a372c6a77669937bb39c698e52f1491e8"
+dependencies = [
+ "glob",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "termcolor",
+ "toml 0.8.15",
+]
+
+[[package]]
 name = "tvix-build"
 version = "0.1.0"
 dependencies = [
diff --git a/tvix/Cargo.nix b/tvix/Cargo.nix
index 5321a97e8ec3..274d3d1d1ae3 100644
--- a/tvix/Cargo.nix
+++ b/tvix/Cargo.nix
@@ -55,6 +55,26 @@ rec {
       # File a bug if you depend on any for non-debug work!
       debug = internal.debugCrate { inherit packageId; };
     };
+    "nix-compat-derive" = rec {
+      packageId = "nix-compat-derive";
+      build = internal.buildRustCrateWithFeatures {
+        packageId = "nix-compat-derive";
+      };
+
+      # Debug support which might change between releases.
+      # File a bug if you depend on any for non-debug work!
+      debug = internal.debugCrate { inherit packageId; };
+    };
+    "nix-compat-derive-tests" = rec {
+      packageId = "nix-compat-derive-tests";
+      build = internal.buildRustCrateWithFeatures {
+        packageId = "nix-compat-derive-tests";
+      };
+
+      # Debug support which might change between releases.
+      # File a bug if you depend on any for non-debug work!
+      debug = internal.debugCrate { inherit packageId; };
+    };
     "tvix-build" = rec {
       packageId = "tvix-build";
       build = internal.buildRustCrateWithFeatures {
@@ -7396,6 +7416,12 @@ rec {
             packageId = "mimalloc";
           }
           {
+            name = "nix-compat-derive";
+            packageId = "nix-compat-derive";
+            optional = true;
+            usesDefaultFeatures = false;
+          }
+          {
             name = "nom";
             packageId = "nom";
           }
@@ -7488,12 +7514,115 @@ rec {
         features = {
           "async" = [ "tokio" ];
           "bytes" = [ "dep:bytes" ];
-          "default" = [ "async" "wire" ];
+          "default" = [ "async" "wire" "nix-compat-derive" ];
+          "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
           "tokio" = [ "dep:tokio" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];
         };
-        resolvedDefaultFeatures = [ "async" "bytes" "default" "pin-project-lite" "tokio" "wire" ];
+        resolvedDefaultFeatures = [ "async" "bytes" "default" "nix-compat-derive" "pin-project-lite" "test" "tokio" "wire" ];
+      };
+      "nix-compat-derive" = rec {
+        crateName = "nix-compat-derive";
+        version = "0.1.0";
+        edition = "2021";
+        src = lib.cleanSourceWith { filter = sourceFilter; src = ./nix-compat-derive; };
+        procMacro = true;
+        libName = "nix_compat_derive";
+        dependencies = [
+          {
+            name = "proc-macro2";
+            packageId = "proc-macro2";
+            features = [ "proc-macro" ];
+          }
+          {
+            name = "quote";
+            packageId = "quote";
+            features = [ "proc-macro" ];
+          }
+          {
+            name = "syn";
+            packageId = "syn 2.0.72";
+            features = [ "full" "extra-traits" ];
+          }
+        ];
+        devDependencies = [
+          {
+            name = "hex-literal";
+            packageId = "hex-literal";
+          }
+          {
+            name = "nix-compat";
+            packageId = "nix-compat";
+            usesDefaultFeatures = false;
+            features = [ "async" "wire" "test" ];
+          }
+          {
+            name = "pretty_assertions";
+            packageId = "pretty_assertions";
+          }
+          {
+            name = "rstest";
+            packageId = "rstest";
+          }
+          {
+            name = "tokio";
+            packageId = "tokio";
+            features = [ "io-util" "macros" ];
+          }
+          {
+            name = "tokio-test";
+            packageId = "tokio-test";
+          }
+        ];
+        features = {
+          "default" = [ "external" ];
+        };
+        resolvedDefaultFeatures = [ "default" "external" ];
+      };
+      "nix-compat-derive-tests" = rec {
+        crateName = "nix-compat-derive-tests";
+        version = "0.1.0";
+        edition = "2021";
+        src = lib.cleanSourceWith { filter = sourceFilter; src = ./nix-compat-derive-tests; };
+        devDependencies = [
+          {
+            name = "hex-literal";
+            packageId = "hex-literal";
+          }
+          {
+            name = "nix-compat";
+            packageId = "nix-compat";
+            features = [ "test" "wire" ];
+          }
+          {
+            name = "nix-compat-derive";
+            packageId = "nix-compat-derive";
+          }
+          {
+            name = "pretty_assertions";
+            packageId = "pretty_assertions";
+          }
+          {
+            name = "rstest";
+            packageId = "rstest";
+          }
+          {
+            name = "tokio";
+            packageId = "tokio";
+            features = [ "io-util" "macros" ];
+          }
+          {
+            name = "tokio-test";
+            packageId = "tokio-test";
+          }
+          {
+            name = "trybuild";
+            packageId = "trybuild";
+          }
+        ];
+        features = { };
+        resolvedDefaultFeatures = [ "compile-tests" ];
       };
       "nohash-hasher" = rec {
         crateName = "nohash-hasher";
@@ -15498,6 +15627,45 @@ rec {
         ];
 
       };
+      "trybuild" = rec {
+        crateName = "trybuild";
+        version = "1.0.99";
+        edition = "2021";
+        sha256 = "1s4i2hpyb66676xkg6b6fxm2qdsawj5lfad8ds68vgn46q6sayi0";
+        authors = [
+          "David Tolnay <dtolnay@gmail.com>"
+        ];
+        dependencies = [
+          {
+            name = "glob";
+            packageId = "glob";
+          }
+          {
+            name = "serde";
+            packageId = "serde";
+          }
+          {
+            name = "serde_derive";
+            packageId = "serde_derive";
+          }
+          {
+            name = "serde_json";
+            packageId = "serde_json";
+          }
+          {
+            name = "termcolor";
+            packageId = "termcolor";
+          }
+          {
+            name = "toml";
+            packageId = "toml 0.8.15";
+          }
+        ];
+        features = {
+          "diff" = [ "dissimilar" ];
+          "dissimilar" = [ "dep:dissimilar" ];
+        };
+      };
       "tvix-build" = rec {
         crateName = "tvix-build";
         version = "0.1.0";
diff --git a/tvix/Cargo.toml b/tvix/Cargo.toml
index 53b9134a567b..175125e152d6 100644
--- a/tvix/Cargo.toml
+++ b/tvix/Cargo.toml
@@ -27,6 +27,8 @@ members = [
   "glue",
   "nar-bridge",
   "nix-compat",
+  "nix-compat-derive",
+  "nix-compat-derive-tests",
   "serde",
   "store",
   "tracing",
diff --git a/tvix/nix-compat-derive-tests/Cargo.toml b/tvix/nix-compat-derive-tests/Cargo.toml
new file mode 100644
index 000000000000..31a334b920f3
--- /dev/null
+++ b/tvix/nix-compat-derive-tests/Cargo.toml
@@ -0,0 +1,27 @@
+[package]
+name = "nix-compat-derive-tests"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+compile-tests = []
+
+[dev-dependencies]
+hex-literal = "0.4.1"
+pretty_assertions = "1.4.0"
+rstest = "0.19.0"
+tokio-test = "0.4.3"
+trybuild = "1.0.96"
+
+[dev-dependencies.nix-compat]
+version = "0.1.0"
+path = "../nix-compat"
+features = ["test", "wire"]
+
+[dev-dependencies.nix-compat-derive]
+version = "0.1.0"
+path = "../nix-compat-derive"
+
+[dev-dependencies.tokio]
+version = "^1.38"
+features = ["io-util", "macros"]
diff --git a/tvix/nix-compat-derive-tests/default.nix b/tvix/nix-compat-derive-tests/default.nix
new file mode 100644
index 000000000000..cabe9ad13780
--- /dev/null
+++ b/tvix/nix-compat-derive-tests/default.nix
@@ -0,0 +1,5 @@
+{ depot, ... }:
+
+depot.tvix.crates.workspaceMembers.nix-compat-derive-tests.build.override {
+  runTests = true;
+}
diff --git a/tvix/nix-compat-derive-tests/tests/read_derive.rs b/tvix/nix-compat-derive-tests/tests/read_derive.rs
new file mode 100644
index 000000000000..055d70cf046e
--- /dev/null
+++ b/tvix/nix-compat-derive-tests/tests/read_derive.rs
@@ -0,0 +1,417 @@
+use std::str::FromStr;
+
+use nix_compat::nix_daemon::de::mock::{Builder, Error};
+use nix_compat::nix_daemon::de::NixRead;
+use nix_compat_derive::NixDeserialize;
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct UnitTest;
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct EmptyTupleTest();
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct StructTest {
+    first: u64,
+    second: String,
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct TupleTest(u64, String);
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct StructVersionTest {
+    test: u64,
+    #[nix(version = "20..")]
+    hello: String,
+}
+
+fn default_test() -> StructVersionTest {
+    StructVersionTest {
+        test: 89,
+        hello: String::from("klomp"),
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct TupleVersionTest(u64, #[nix(version = "25..")] String);
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+pub struct TupleVersionDefaultTest(
+    u64,
+    #[nix(version = "..25", default = "default_test")] StructVersionTest,
+);
+
+#[tokio::test]
+async fn read_unit() {
+    let mut mock = Builder::new().build();
+    let v: UnitTest = mock.read_value().await.unwrap();
+    assert_eq!(UnitTest, v);
+}
+
+#[tokio::test]
+async fn read_empty_tuple() {
+    let mut mock = Builder::new().build();
+    let v: EmptyTupleTest = mock.read_value().await.unwrap();
+    assert_eq!(EmptyTupleTest(), v);
+}
+
+#[tokio::test]
+async fn read_struct() {
+    let mut mock = Builder::new().read_number(89).read_slice(b"klomp").build();
+    let v: StructTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        StructTest {
+            first: 89,
+            second: String::from("klomp"),
+        },
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_tuple() {
+    let mut mock = Builder::new().read_number(89).read_slice(b"klomp").build();
+    let v: TupleTest = mock.read_value().await.unwrap();
+    assert_eq!(TupleTest(89, String::from("klomp")), v);
+}
+
+#[tokio::test]
+async fn read_struct_version() {
+    let mut mock = Builder::new()
+        .version((1, 20))
+        .read_number(89)
+        .read_slice(b"klomp")
+        .build();
+    let v: StructVersionTest = mock.read_value().await.unwrap();
+    assert_eq!(default_test(), v);
+}
+
+#[tokio::test]
+async fn read_struct_without_version() {
+    let mut mock = Builder::new().version((1, 19)).read_number(89).build();
+    let v: StructVersionTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        StructVersionTest {
+            test: 89,
+            hello: String::new(),
+        },
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_tuple_version() {
+    let mut mock = Builder::new()
+        .version((1, 26))
+        .read_number(89)
+        .read_slice(b"klomp")
+        .build();
+    let v: TupleVersionTest = mock.read_value().await.unwrap();
+    assert_eq!(TupleVersionTest(89, "klomp".into()), v);
+}
+
+#[tokio::test]
+async fn read_tuple_without_version() {
+    let mut mock = Builder::new().version((1, 19)).read_number(89).build();
+    let v: TupleVersionTest = mock.read_value().await.unwrap();
+    assert_eq!(TupleVersionTest(89, String::new()), v);
+}
+
+#[tokio::test]
+async fn read_complex_1() {
+    let mut mock = Builder::new()
+        .version((1, 19))
+        .read_number(999)
+        .read_number(666)
+        .build();
+    let v: TupleVersionDefaultTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        TupleVersionDefaultTest(
+            999,
+            StructVersionTest {
+                test: 666,
+                hello: String::new()
+            }
+        ),
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_complex_2() {
+    let mut mock = Builder::new()
+        .version((1, 20))
+        .read_number(999)
+        .read_number(666)
+        .read_slice(b"The quick brown \xF0\x9F\xA6\x8A jumps over 13 lazy \xF0\x9F\x90\xB6.")
+        .build();
+    let v: TupleVersionDefaultTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        TupleVersionDefaultTest(
+            999,
+            StructVersionTest {
+                test: 666,
+                hello: String::from("The quick brown 🦊 jumps over 13 lazy 🐶.")
+            }
+        ),
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_complex_3() {
+    let mut mock = Builder::new().version((1, 25)).read_number(999).build();
+    let v: TupleVersionDefaultTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        TupleVersionDefaultTest(
+            999,
+            StructVersionTest {
+                test: 89,
+                hello: String::from("klomp")
+            }
+        ),
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_complex_4() {
+    let mut mock = Builder::new().version((1, 26)).read_number(999).build();
+    let v: TupleVersionDefaultTest = mock.read_value().await.unwrap();
+    assert_eq!(
+        TupleVersionDefaultTest(
+            999,
+            StructVersionTest {
+                test: 89,
+                hello: String::from("klomp")
+            }
+        ),
+        v
+    );
+}
+
+#[tokio::test]
+async fn read_field_invalid_data() {
+    let mut mock = Builder::new()
+        .read_number(666)
+        .read_slice(b"The quick brown \xED\xA0\x80 jumped.")
+        .build();
+    let err = mock.read_value::<StructTest>().await.unwrap_err();
+    assert_eq!(
+        Error::InvalidData("invalid utf-8 sequence of 1 bytes from index 16".into()),
+        err
+    );
+}
+
+#[tokio::test]
+async fn read_field_missing_data() {
+    let mut mock = Builder::new().read_number(666).build();
+    let err = mock.read_value::<StructTest>().await.unwrap_err();
+    assert_eq!(Error::MissingData("unexpected end-of-file".into()), err);
+}
+
+#[tokio::test]
+async fn read_field_no_data() {
+    let mut mock = Builder::new().build();
+    let err = mock.read_value::<StructTest>().await.unwrap_err();
+    assert_eq!(Error::MissingData("unexpected end-of-file".into()), err);
+}
+
+#[tokio::test]
+async fn read_field_reader_error_first() {
+    let mut mock = Builder::new()
+        .read_number_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<StructTest>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[tokio::test]
+async fn read_field_reader_error_later() {
+    let mut mock = Builder::new()
+        .read_number(999)
+        .read_bytes_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<StructTest>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+#[nix(from_str)]
+struct TestFromStr;
+
+impl FromStr for TestFromStr {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s == "test" {
+            Ok(TestFromStr)
+        } else {
+            Err(s.into())
+        }
+    }
+}
+
+#[tokio::test]
+async fn read_from_str() {
+    let mut mock = Builder::new().read_slice(b"test").build();
+    let value = mock.read_value::<TestFromStr>().await.unwrap();
+    assert_eq!(TestFromStr, value);
+}
+
+#[tokio::test]
+async fn read_from_str_invalid_data() {
+    let mut mock = Builder::new().read_slice(b"wrong string").build();
+    let err = mock.read_value::<TestFromStr>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("wrong string".into()), err);
+}
+
+#[tokio::test]
+async fn read_from_str_invalid_string() {
+    let mut mock = Builder::new()
+        .read_slice(b"The quick brown \xED\xA0\x80 jumped.")
+        .build();
+    let err = mock.read_value::<TestFromStr>().await.unwrap_err();
+    assert_eq!(
+        Error::InvalidData("invalid utf-8 sequence of 1 bytes from index 16".into()),
+        err
+    );
+}
+
+#[tokio::test]
+async fn read_from_str_reader_error() {
+    let mut mock = Builder::new()
+        .read_bytes_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<TestFromStr>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+#[nix(try_from = "u64")]
+struct TestTryFromU64;
+
+impl TryFrom<u64> for TestTryFromU64 {
+    type Error = u64;
+
+    fn try_from(value: u64) -> Result<TestTryFromU64, Self::Error> {
+        if value == 42 {
+            Ok(TestTryFromU64)
+        } else {
+            Err(value)
+        }
+    }
+}
+
+#[tokio::test]
+async fn read_try_from_u64() {
+    let mut mock = Builder::new().read_number(42).build();
+    let value = mock.read_value::<TestTryFromU64>().await.unwrap();
+    assert_eq!(TestTryFromU64, value);
+}
+
+#[tokio::test]
+async fn read_try_from_u64_invalid_data() {
+    let mut mock = Builder::new().read_number(666).build();
+    let err = mock.read_value::<TestTryFromU64>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("666".into()), err);
+}
+
+#[tokio::test]
+async fn read_try_from_u64_reader_error() {
+    let mut mock = Builder::new()
+        .read_number_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<TestTryFromU64>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+#[nix(from = "u64")]
+struct TestFromU64;
+
+impl From<u64> for TestFromU64 {
+    fn from(_value: u64) -> TestFromU64 {
+        TestFromU64
+    }
+}
+
+#[tokio::test]
+async fn read_from_u64() {
+    let mut mock = Builder::new().read_number(42).build();
+    let value = mock.read_value::<TestFromU64>().await.unwrap();
+    assert_eq!(TestFromU64, value);
+}
+
+#[tokio::test]
+async fn read_from_u64_reader_error() {
+    let mut mock = Builder::new()
+        .read_number_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<TestFromU64>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[derive(Debug, PartialEq, Eq, NixDeserialize)]
+enum TestEnum {
+    #[nix(version = "..=19")]
+    Pre20(TestTryFromU64),
+    #[nix(version = "20..")]
+    Post20(StructVersionTest),
+}
+
+#[tokio::test]
+async fn read_enum_19() {
+    let mut mock = Builder::new().version((1, 19)).read_number(42).build();
+    let value = mock.read_value::<TestEnum>().await.unwrap();
+    assert_eq!(TestEnum::Pre20(TestTryFromU64), value);
+}
+
+#[tokio::test]
+async fn read_enum_20() {
+    let mut mock = Builder::new()
+        .version((1, 20))
+        .read_number(42)
+        .read_slice(b"klomp")
+        .build();
+    let value = mock.read_value::<TestEnum>().await.unwrap();
+    assert_eq!(
+        TestEnum::Post20(StructVersionTest {
+            test: 42,
+            hello: "klomp".into(),
+        }),
+        value
+    );
+}
+
+#[tokio::test]
+async fn read_enum_reader_error() {
+    let mut mock = Builder::new()
+        .version((1, 19))
+        .read_number_error(Error::InvalidData("Bad reader".into()))
+        .build();
+    let err = mock.read_value::<TestEnum>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("Bad reader".into()), err);
+}
+
+#[tokio::test]
+async fn read_enum_invalid_data_19() {
+    let mut mock = Builder::new().version((1, 19)).read_number(666).build();
+    let err = mock.read_value::<TestEnum>().await.unwrap_err();
+    assert_eq!(Error::InvalidData("666".into()), err);
+}
+
+#[tokio::test]
+async fn read_enum_invalid_data_20() {
+    let mut mock = Builder::new()
+        .version((1, 20))
+        .read_number(666)
+        .read_slice(b"The quick brown \xED\xA0\x80 jumped.")
+        .build();
+    let err = mock.read_value::<TestEnum>().await.unwrap_err();
+    assert_eq!(
+        Error::InvalidData("invalid utf-8 sequence of 1 bytes from index 16".into()),
+        err
+    );
+}
diff --git a/tvix/nix-compat-derive-tests/tests/ui.rs b/tvix/nix-compat-derive-tests/tests/ui.rs
new file mode 100644
index 000000000000..6a7bffeaf832
--- /dev/null
+++ b/tvix/nix-compat-derive-tests/tests/ui.rs
@@ -0,0 +1,6 @@
+#[cfg(feature = "compile-tests")]
+#[test]
+fn ui() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/*.rs");
+}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.rs
new file mode 100644
index 000000000000..f77469679999
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_bad_type.stderr
new file mode 100644
index 000000000000..12ffdc83c726
--- /dev/null
+++ b/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`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.rs
new file mode 100644
index 000000000000..ab559f2b81c8
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_enum_non_exaustive.stderr
new file mode 100644
index 000000000000..8a46d9439e35
--- /dev/null
+++ b/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)
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.rs
new file mode 100644
index 000000000000..913b7c4f7e59
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_missing.stderr
new file mode 100644
index 000000000000..0124010cf10c
--- /dev/null
+++ b/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`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.rs
new file mode 100644
index 000000000000..36cd4b153740
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_error_not_display.stderr
new file mode 100644
index 000000000000..8283ed5340f3
--- /dev/null
+++ b/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`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.rs
new file mode 100644
index 000000000000..a959db57e640
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.stderr
new file mode 100644
index 000000000000..f68f588011fc
--- /dev/null
+++ b/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
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default.rs
new file mode 100644
index 000000000000..e9df62845518
--- /dev/null
+++ b/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() {}
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);
+  |
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.rs
new file mode 100644
index 000000000000..4f319c069dca
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_missing_default_path.stderr
new file mode 100644
index 000000000000..bb9af749128d
--- /dev/null
+++ b/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`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.rs
new file mode 100644
index 000000000000..cc2ab5bfbc11
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_remote_missing_attr.stderr
new file mode 100644
index 000000000000..a1c18adc6e48
--- /dev/null
+++ b/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);
+   |                         ^^^^^^^^^^^^^^
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.rs
new file mode 100644
index 000000000000..7f8ad6bbfc4e
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_error_not_display.stderr
new file mode 100644
index 000000000000..8e55a3c56189
--- /dev/null
+++ b/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`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.rs b/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.rs
new file mode 100644
index 000000000000..899095ae3542
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.stderr b/tvix/nix-compat-derive-tests/tests/ui/deserialize_try_from_missing.stderr
new file mode 100644
index 000000000000..9605d1f3378f
--- /dev/null
+++ b/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>`
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.rs b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.rs
new file mode 100644
index 000000000000..d87831cecf51
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.stderr b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default.stderr
new file mode 100644
index 000000000000..acb1bc2a47bc
--- /dev/null
+++ b/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)]
+  |                     ^^
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.rs b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.rs
new file mode 100644
index 000000000000..fbde8ffbc2b0
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.stderr b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_default_path.stderr
new file mode 100644
index 000000000000..7628d4c83bea
--- /dev/null
+++ b/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")]
+  |                     ^^^^
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.rs b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.rs
new file mode 100644
index 000000000000..690e76a20fe6
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.stderr b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_nix.stderr
new file mode 100644
index 000000000000..da3d2d9aab47
--- /dev/null
+++ b/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]
+  |       ^^^
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.rs b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.rs
new file mode 100644
index 000000000000..35b3b05c23e1
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.stderr b/tvix/nix-compat-derive-tests/tests/ui/parse_bad_version.stderr
new file mode 100644
index 000000000000..48cc817fac9d
--- /dev/null
+++ b/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)]
+  |                     ^^
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.rs b/tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.rs
new file mode 100644
index 000000000000..9eaa743ed2b6
--- /dev/null
+++ b/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() {}
diff --git a/tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.stderr b/tvix/nix-compat-derive-tests/tests/ui/parse_mising_version.stderr
new file mode 100644
index 000000000000..79f048e11198
--- /dev/null
+++ b/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)]
+  |                  ^
diff --git a/tvix/nix-compat-derive/Cargo.toml b/tvix/nix-compat-derive/Cargo.toml
new file mode 100644
index 000000000000..dea8ab5ab159
--- /dev/null
+++ b/tvix/nix-compat-derive/Cargo.toml
@@ -0,0 +1,32 @@
+[package]
+name = "nix-compat-derive"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[features]
+external = []
+default = ["external"]
+
+
+[dependencies]
+proc-macro2 = { version = "1.0.86",  features = ["proc-macro"] }
+quote = { version = "1.0.36", features = ["proc-macro"] }
+syn = { version = "2.0.72", features = ["full", "extra-traits"] }
+
+[dev-dependencies]
+hex-literal = "0.4.1"
+pretty_assertions = "1.4.0"
+rstest = "0.19.0"
+tokio-test = "0.4.3"
+
+[dev-dependencies.tokio]
+version = "^1.38"
+features = ["io-util", "macros"]
+
+[dev-dependencies.nix-compat]
+path = "../nix-compat"
+default-features = false
+features = ["async", "wire", "test"]
diff --git a/tvix/nix-compat-derive/default.nix b/tvix/nix-compat-derive/default.nix
new file mode 100644
index 000000000000..e6636e7f2510
--- /dev/null
+++ b/tvix/nix-compat-derive/default.nix
@@ -0,0 +1,5 @@
+{ depot, lib, ... }:
+
+depot.tvix.crates.workspaceMembers.nix-compat-derive.build.override {
+  runTests = true;
+}
diff --git a/tvix/nix-compat-derive/src/de.rs b/tvix/nix-compat-derive/src/de.rs
new file mode 100644
index 000000000000..ee79ea9d1012
--- /dev/null
+++ b/tvix/nix-compat-derive/src/de.rs
@@ -0,0 +1,272 @@
+use proc_macro2::{Span, TokenStream};
+use quote::{quote, quote_spanned, ToTokens};
+use syn::spanned::Spanned;
+use syn::{DeriveInput, Generics, Path, Type};
+
+use crate::internal::attrs::Default;
+use crate::internal::inputs::RemoteInput;
+use crate::internal::{attrs, Container, Context, Data, Field, Remote, Style, Variant};
+
+pub fn expand_nix_deserialize(nnixrs: Path, input: &mut DeriveInput) -> syn::Result<TokenStream> {
+    let cx = Context::new();
+    let cont = Container::from_ast(&cx, nnixrs, input);
+    cx.check()?;
+    let cont = cont.unwrap();
+
+    let ty = cont.ident_type();
+    let body = nix_deserialize_body(&cont);
+    let crate_path = cont.crate_path();
+
+    Ok(nix_deserialize_impl(
+        crate_path,
+        &ty,
+        &cont.original.generics,
+        body,
+    ))
+}
+
+pub fn expand_nix_deserialize_remote(
+    crate_path: Path,
+    input: &RemoteInput,
+) -> syn::Result<TokenStream> {
+    let cx = Context::new();
+    let remote = Remote::from_ast(&cx, crate_path, input);
+    cx.check()?;
+    let remote = remote.unwrap();
+
+    let crate_path = remote.crate_path();
+    let body = nix_deserialize_body_from(crate_path, &remote.attrs).expect("From tokenstream");
+    let generics = Generics::default();
+    Ok(nix_deserialize_impl(crate_path, remote.ty, &generics, body))
+}
+
+fn nix_deserialize_impl(
+    crate_path: &Path,
+    ty: &Type,
+    generics: &Generics,
+    body: TokenStream,
+) -> TokenStream {
+    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+
+    quote! {
+        #[automatically_derived]
+        impl #impl_generics #crate_path::nix_daemon::de::NixDeserialize for #ty #ty_generics
+            #where_clause
+        {
+            #[allow(clippy::manual_async_fn)]
+            fn try_deserialize<R>(reader: &mut R) -> impl ::std::future::Future<Output=Result<Option<Self>, R::Error>> + Send + '_
+                where R: ?Sized + #crate_path::nix_daemon::de::NixRead + Send,
+            {
+                #body
+            }
+        }
+    }
+}
+
+fn nix_deserialize_body_from(
+    crate_path: &syn::Path,
+    attrs: &attrs::Container,
+) -> Option<TokenStream> {
+    if let Some(span) = attrs.from_str.as_ref() {
+        Some(nix_deserialize_from_str(crate_path, span.span()))
+    } else if let Some(type_from) = attrs.type_from.as_ref() {
+        Some(nix_deserialize_from(type_from))
+    } else {
+        attrs
+            .type_try_from
+            .as_ref()
+            .map(|type_try_from| nix_deserialize_try_from(crate_path, type_try_from))
+    }
+}
+
+fn nix_deserialize_body(cont: &Container) -> TokenStream {
+    if let Some(tokens) = nix_deserialize_body_from(cont.crate_path(), &cont.attrs) {
+        tokens
+    } else {
+        match &cont.data {
+            Data::Struct(style, fields) => nix_deserialize_struct(*style, fields),
+            Data::Enum(variants) => nix_deserialize_enum(variants),
+        }
+    }
+}
+
+fn nix_deserialize_struct(style: Style, fields: &[Field<'_>]) -> TokenStream {
+    let read_fields = fields.iter().map(|f| {
+        let field = f.var_ident();
+        let ty = f.ty;
+        let read_value = quote_spanned! {
+            ty.span()=> if first__ {
+                first__ = false;
+                if let Some(v) = reader.try_read_value::<#ty>().await? {
+                    v
+                } else {
+                    return Ok(None);
+                }
+            } else {
+                reader.read_value::<#ty>().await?
+            }
+        };
+        if let Some(version) = f.attrs.version.as_ref() {
+            let default = match &f.attrs.default {
+                Default::Default => quote_spanned!(ty.span()=>::std::default::Default::default),
+                Default::Path(path) => path.to_token_stream(),
+                _ => panic!("No default for versioned field"),
+            };
+            quote! {
+                let #field : #ty = if (#version).contains(&reader.version().minor()) {
+                    #read_value
+                } else {
+                    #default()
+                };
+            }
+        } else {
+            quote! {
+                let #field : #ty = #read_value;
+            }
+        }
+    });
+
+    let field_names = fields.iter().map(|f| f.var_ident());
+    let construct = match style {
+        Style::Struct => {
+            quote! {
+                Self { #(#field_names),* }
+            }
+        }
+        Style::Tuple => {
+            quote! {
+                Self(#(#field_names),*)
+            }
+        }
+        Style::Unit => quote!(Self),
+    };
+    quote! {
+        #[allow(unused_assignments)]
+        async move {
+            let mut first__ = true;
+            #(#read_fields)*
+            Ok(Some(#construct))
+        }
+    }
+}
+
+fn nix_deserialize_variant(variant: &Variant<'_>) -> TokenStream {
+    let ident = variant.ident;
+    let read_fields = variant.fields.iter().map(|f| {
+        let field = f.var_ident();
+        let ty = f.ty;
+        let read_value = quote_spanned! {
+            ty.span()=> if first__ {
+                first__ = false;
+                if let Some(v) = reader.try_read_value::<#ty>().await? {
+                    v
+                } else {
+                    return Ok(None);
+                }
+            } else {
+                reader.read_value::<#ty>().await?
+            }
+        };
+        if let Some(version) = f.attrs.version.as_ref() {
+            let default = match &f.attrs.default {
+                Default::Default => quote_spanned!(ty.span()=>::std::default::Default::default),
+                Default::Path(path) => path.to_token_stream(),
+                _ => panic!("No default for versioned field"),
+            };
+            quote! {
+                let #field : #ty = if (#version).contains(&reader.version().minor()) {
+                    #read_value
+                } else {
+                    #default()
+                };
+            }
+        } else {
+            quote! {
+                let #field : #ty = #read_value;
+            }
+        }
+    });
+    let field_names = variant.fields.iter().map(|f| f.var_ident());
+    let construct = match variant.style {
+        Style::Struct => {
+            quote! {
+                Self::#ident { #(#field_names),* }
+            }
+        }
+        Style::Tuple => {
+            quote! {
+                Self::#ident(#(#field_names),*)
+            }
+        }
+        Style::Unit => quote!(Self::#ident),
+    };
+    let version = &variant.attrs.version;
+    quote! {
+        #version => {
+            #(#read_fields)*
+            Ok(Some(#construct))
+        }
+    }
+}
+
+fn nix_deserialize_enum(variants: &[Variant<'_>]) -> TokenStream {
+    let match_variant = variants
+        .iter()
+        .map(|variant| nix_deserialize_variant(variant));
+    quote! {
+        #[allow(unused_assignments)]
+        async move {
+            let mut first__ = true;
+            match reader.version().minor() {
+                #(#match_variant)*
+            }
+        }
+    }
+}
+
+fn nix_deserialize_from(ty: &Type) -> TokenStream {
+    quote_spanned! {
+        ty.span() =>
+        async move {
+            if let Some(value) = reader.try_read_value::<#ty>().await? {
+                Ok(Some(<Self as ::std::convert::From<#ty>>::from(value)))
+            } else {
+                Ok(None)
+            }
+        }
+    }
+}
+
+fn nix_deserialize_try_from(crate_path: &Path, ty: &Type) -> TokenStream {
+    quote_spanned! {
+        ty.span() =>
+        async move {
+            use #crate_path::nix_daemon::de::Error;
+            if let Some(item) = reader.try_read_value::<#ty>().await? {
+                <Self as ::std::convert::TryFrom<#ty>>::try_from(item)
+                    .map_err(Error::invalid_data)
+                    .map(Some)
+            } else {
+                Ok(None)
+            }
+        }
+    }
+}
+
+fn nix_deserialize_from_str(crate_path: &Path, span: Span) -> TokenStream {
+    quote_spanned! {
+        span =>
+        async move {
+            use #crate_path::nix_daemon::de::Error;
+            if let Some(buf) = reader.try_read_bytes().await? {
+                let s = ::std::str::from_utf8(&buf)
+                    .map_err(Error::invalid_data)?;
+                <Self as ::std::str::FromStr>::from_str(s)
+                    .map_err(Error::invalid_data)
+                    .map(Some)
+            } else {
+                Ok(None)
+            }
+        }
+    }
+}
diff --git a/tvix/nix-compat-derive/src/internal/attrs.rs b/tvix/nix-compat-derive/src/internal/attrs.rs
new file mode 100644
index 000000000000..dbc959d1e917
--- /dev/null
+++ b/tvix/nix-compat-derive/src/internal/attrs.rs
@@ -0,0 +1,358 @@
+use quote::ToTokens;
+use syn::meta::ParseNestedMeta;
+use syn::parse::Parse;
+use syn::{parse_quote, Attribute, Expr, ExprLit, ExprPath, Lit, Token};
+
+use super::symbol::{Symbol, CRATE, DEFAULT, FROM, FROM_STR, NIX, TRY_FROM, VERSION};
+use super::Context;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Default {
+    None,
+    #[allow(clippy::enum_variant_names)]
+    Default,
+    Path(ExprPath),
+}
+
+impl Default {
+    pub fn is_none(&self) -> bool {
+        matches!(self, Default::None)
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Field {
+    pub default: Default,
+    pub version: Option<syn::ExprRange>,
+}
+
+impl Field {
+    pub fn from_ast(ctx: &Context, attrs: &Vec<Attribute>) -> Field {
+        let mut version = None;
+        let mut default = Default::None;
+        for attr in attrs {
+            if attr.path() != NIX {
+                continue;
+            }
+            if let Err(err) = attr.parse_nested_meta(|meta| {
+                if meta.path == VERSION {
+                    version = parse_lit(ctx, &meta, VERSION)?;
+                } else if meta.path == DEFAULT {
+                    if meta.input.peek(Token![=]) {
+                        if let Some(path) = parse_lit(ctx, &meta, DEFAULT)? {
+                            default = Default::Path(path);
+                        }
+                    } else {
+                        default = Default::Default;
+                    }
+                } else {
+                    let path = meta.path.to_token_stream().to_string();
+                    return Err(meta.error(format_args!("unknown nix field attribute '{}'", path)));
+                }
+                Ok(())
+            }) {
+                eprintln!("{:?}", err.span().source_text());
+                ctx.syn_error(err);
+            }
+        }
+        if version.is_some() && default.is_none() {
+            default = Default::Default;
+        }
+
+        Field { default, version }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Variant {
+    pub version: syn::ExprRange,
+}
+
+impl Variant {
+    pub fn from_ast(ctx: &Context, attrs: &Vec<Attribute>) -> Variant {
+        let mut version = parse_quote!(..);
+        for attr in attrs {
+            if attr.path() != NIX {
+                continue;
+            }
+            if let Err(err) = attr.parse_nested_meta(|meta| {
+                if meta.path == VERSION {
+                    if let Some(v) = parse_lit(ctx, &meta, VERSION)? {
+                        version = v;
+                    }
+                } else {
+                    let path = meta.path.to_token_stream().to_string();
+                    return Err(
+                        meta.error(format_args!("unknown nix variant attribute '{}'", path))
+                    );
+                }
+                Ok(())
+            }) {
+                eprintln!("{:?}", err.span().source_text());
+                ctx.syn_error(err);
+            }
+        }
+
+        Variant { version }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Container {
+    pub from_str: Option<syn::Path>,
+    pub type_from: Option<syn::Type>,
+    pub type_try_from: Option<syn::Type>,
+    pub crate_path: Option<syn::Path>,
+}
+
+impl Container {
+    pub fn from_ast(ctx: &Context, attrs: &Vec<Attribute>) -> Container {
+        let mut type_from = None;
+        let mut type_try_from = None;
+        let mut crate_path = None;
+        let mut from_str = None;
+
+        for attr in attrs {
+            if attr.path() != NIX {
+                continue;
+            }
+            if let Err(err) = attr.parse_nested_meta(|meta| {
+                if meta.path == FROM {
+                    type_from = parse_lit(ctx, &meta, FROM)?;
+                } else if meta.path == TRY_FROM {
+                    type_try_from = parse_lit(ctx, &meta, TRY_FROM)?;
+                } else if meta.path == FROM_STR {
+                    from_str = Some(meta.path);
+                } else if meta.path == CRATE {
+                    crate_path = parse_lit(ctx, &meta, CRATE)?;
+                } else {
+                    let path = meta.path.to_token_stream().to_string();
+                    return Err(
+                        meta.error(format_args!("unknown nix variant attribute '{}'", path))
+                    );
+                }
+                Ok(())
+            }) {
+                eprintln!("{:?}", err.span().source_text());
+                ctx.syn_error(err);
+            }
+        }
+
+        Container {
+            from_str,
+            type_from,
+            type_try_from,
+            crate_path,
+        }
+    }
+}
+
+pub fn get_lit_str(
+    ctx: &Context,
+    meta: &ParseNestedMeta,
+    attr: Symbol,
+) -> syn::Result<Option<syn::LitStr>> {
+    let expr: Expr = meta.value()?.parse()?;
+    let mut value = &expr;
+    while let Expr::Group(e) = value {
+        value = &e.expr;
+    }
+    if let Expr::Lit(ExprLit {
+        lit: Lit::Str(s), ..
+    }) = value
+    {
+        Ok(Some(s.clone()))
+    } else {
+        ctx.error_spanned(
+            expr,
+            format_args!("expected nix attribute {} to be string", attr),
+        );
+        Ok(None)
+    }
+}
+
+pub fn parse_lit<T: Parse>(
+    ctx: &Context,
+    meta: &ParseNestedMeta,
+    attr: Symbol,
+) -> syn::Result<Option<T>> {
+    match get_lit_str(ctx, meta, attr)? {
+        Some(lit) => Ok(Some(lit.parse()?)),
+        None => Ok(None),
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use syn::{parse_quote, Attribute};
+
+    use crate::internal::Context;
+
+    use super::*;
+
+    #[test]
+    fn parse_field_version() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix(version="..34")])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::Default,
+                version: Some(parse_quote!(..34)),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_default() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix(default)])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::Default,
+                version: None,
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_default_path() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix(default="Default::default")])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::Path(parse_quote!(Default::default)),
+                version: None,
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_both() {
+        let attrs: Vec<Attribute> =
+            vec![parse_quote!(#[nix(version="..", default="Default::default")])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::Path(parse_quote!(Default::default)),
+                version: Some(parse_quote!(..)),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_both_rev() {
+        let attrs: Vec<Attribute> =
+            vec![parse_quote!(#[nix(default="Default::default", version="..")])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::Path(parse_quote!(Default::default)),
+                version: Some(parse_quote!(..)),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_no_attr() {
+        let attrs: Vec<Attribute> = vec![];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::None,
+                version: None,
+            }
+        );
+    }
+
+    #[test]
+    fn parse_field_no_subattrs() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix()])];
+        let ctx = Context::new();
+        let field = Field::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            field,
+            Field {
+                default: Default::None,
+                version: None,
+            }
+        );
+    }
+
+    #[test]
+    fn parse_variant_version() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix(version="..34")])];
+        let ctx = Context::new();
+        let variant = Variant::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            variant,
+            Variant {
+                version: parse_quote!(..34),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_variant_no_attr() {
+        let attrs: Vec<Attribute> = vec![];
+        let ctx = Context::new();
+        let variant = Variant::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            variant,
+            Variant {
+                version: parse_quote!(..),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_variant_no_subattrs() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix()])];
+        let ctx = Context::new();
+        let variant = Variant::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            variant,
+            Variant {
+                version: parse_quote!(..),
+            }
+        );
+    }
+
+    #[test]
+    fn parse_container_try_from() {
+        let attrs: Vec<Attribute> = vec![parse_quote!(#[nix(try_from="u64")])];
+        let ctx = Context::new();
+        let container = Container::from_ast(&ctx, &attrs);
+        ctx.check().unwrap();
+        assert_eq!(
+            container,
+            Container {
+                from_str: None,
+                type_from: None,
+                type_try_from: Some(parse_quote!(u64)),
+                crate_path: None,
+            }
+        );
+    }
+}
diff --git a/tvix/nix-compat-derive/src/internal/ctx.rs b/tvix/nix-compat-derive/src/internal/ctx.rs
new file mode 100644
index 000000000000..ba770e044bc2
--- /dev/null
+++ b/tvix/nix-compat-derive/src/internal/ctx.rs
@@ -0,0 +1,50 @@
+use std::cell::RefCell;
+use std::fmt;
+use std::thread::panicking;
+
+use quote::ToTokens;
+
+pub struct Context {
+    errors: RefCell<Option<Vec<syn::Error>>>,
+}
+
+impl Context {
+    pub fn new() -> Context {
+        Context {
+            errors: RefCell::new(Some(Vec::new())),
+        }
+    }
+
+    pub fn syn_error(&self, error: syn::Error) {
+        self.errors
+            .borrow_mut()
+            .as_mut()
+            .take()
+            .unwrap()
+            .push(error);
+    }
+
+    pub fn error_spanned<T: ToTokens, D: fmt::Display>(&self, tokens: T, message: D) {
+        self.syn_error(syn::Error::new_spanned(tokens, message));
+    }
+
+    pub fn check(&self) -> syn::Result<()> {
+        let mut iter = self.errors.borrow_mut().take().unwrap().into_iter();
+        let mut err = match iter.next() {
+            None => return Ok(()),
+            Some(err) => err,
+        };
+        for next_err in iter {
+            err.combine(next_err);
+        }
+        Err(err)
+    }
+}
+
+impl Drop for Context {
+    fn drop(&mut self) {
+        if self.errors.borrow().is_some() && !panicking() {
+            panic!("Context dropped without checking errors");
+        }
+    }
+}
diff --git a/tvix/nix-compat-derive/src/internal/inputs.rs b/tvix/nix-compat-derive/src/internal/inputs.rs
new file mode 100644
index 000000000000..097a141a5d7c
--- /dev/null
+++ b/tvix/nix-compat-derive/src/internal/inputs.rs
@@ -0,0 +1,110 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct RemoteInput {
+    pub attrs: Vec<syn::Attribute>,
+    pub ident: syn::Type,
+}
+
+impl syn::parse::Parse for RemoteInput {
+    fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+        let attrs = input.call(syn::Attribute::parse_outer)?;
+
+        let ident = input.parse::<syn::Type>()?;
+        Ok(RemoteInput { attrs, ident })
+    }
+}
+
+impl quote::ToTokens for RemoteInput {
+    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
+        fn is_outer(attr: &&syn::Attribute) -> bool {
+            match attr.style {
+                syn::AttrStyle::Outer => true,
+                syn::AttrStyle::Inner(_) => false,
+            }
+        }
+        for attr in self.attrs.iter().filter(is_outer) {
+            attr.to_tokens(tokens);
+        }
+        self.ident.to_tokens(tokens);
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use syn::parse_quote;
+    //use syn::parse::Parse;
+
+    use super::*;
+
+    #[test]
+    fn test_input() {
+        let p: RemoteInput = parse_quote!(u64);
+        assert_eq!(
+            p,
+            RemoteInput {
+                attrs: vec![],
+                ident: parse_quote!(u64),
+            }
+        );
+    }
+
+    #[test]
+    fn test_input_attr() {
+        let p: RemoteInput = parse_quote!(
+            #[nix]
+            u64
+        );
+        assert_eq!(
+            p,
+            RemoteInput {
+                attrs: vec![parse_quote!(#[nix])],
+                ident: parse_quote!(u64),
+            }
+        );
+    }
+
+    #[test]
+    fn test_input_attr_multiple() {
+        let p: RemoteInput = parse_quote!(
+            #[nix]
+            #[hello]
+            u64
+        );
+        assert_eq!(
+            p,
+            RemoteInput {
+                attrs: vec![parse_quote!(#[nix]), parse_quote!(#[hello])],
+                ident: parse_quote!(u64),
+            }
+        );
+    }
+
+    #[test]
+    fn test_input_attr_full() {
+        let p: RemoteInput = parse_quote!(
+            #[nix(try_from = "u64")]
+            usize
+        );
+        assert_eq!(
+            p,
+            RemoteInput {
+                attrs: vec![parse_quote!(#[nix(try_from="u64")])],
+                ident: parse_quote!(usize),
+            }
+        );
+    }
+
+    #[test]
+    fn test_input_attr_other() {
+        let p: RemoteInput = parse_quote!(
+            #[muh]
+            u64
+        );
+        assert_eq!(
+            p,
+            RemoteInput {
+                attrs: vec![parse_quote!(#[muh])],
+                ident: parse_quote!(u64),
+            }
+        );
+    }
+}
diff --git a/tvix/nix-compat-derive/src/internal/mod.rs b/tvix/nix-compat-derive/src/internal/mod.rs
new file mode 100644
index 000000000000..20b243221619
--- /dev/null
+++ b/tvix/nix-compat-derive/src/internal/mod.rs
@@ -0,0 +1,183 @@
+use syn::punctuated::Punctuated;
+use syn::spanned::Spanned;
+use syn::Token;
+
+pub mod attrs;
+mod ctx;
+pub mod inputs;
+mod symbol;
+
+pub use ctx::Context;
+
+pub struct Field<'a> {
+    pub member: syn::Member,
+    pub ty: &'a syn::Type,
+    pub attrs: attrs::Field,
+    pub original: &'a syn::Field,
+}
+
+impl<'a> Field<'a> {
+    pub fn from_ast(ctx: &Context, idx: usize, field: &'a syn::Field) -> Field<'a> {
+        let attrs = attrs::Field::from_ast(ctx, &field.attrs);
+        let member = match &field.ident {
+            Some(id) => syn::Member::Named(id.clone()),
+            None => syn::Member::Unnamed(idx.into()),
+        };
+        Field {
+            member,
+            attrs,
+            ty: &field.ty,
+            original: field,
+        }
+    }
+
+    pub fn var_ident(&self) -> syn::Ident {
+        match &self.member {
+            syn::Member::Named(name) => name.clone(),
+            syn::Member::Unnamed(idx) => {
+                syn::Ident::new(&format!("field{}", idx.index), self.original.span())
+            }
+        }
+    }
+}
+
+pub struct Variant<'a> {
+    pub ident: &'a syn::Ident,
+    pub attrs: attrs::Variant,
+    pub style: Style,
+    pub fields: Vec<Field<'a>>,
+    //pub original: &'a syn::Variant,
+}
+
+impl<'a> Variant<'a> {
+    pub fn from_ast(ctx: &Context, variant: &'a syn::Variant) -> Self {
+        let attrs = attrs::Variant::from_ast(ctx, &variant.attrs);
+        let (style, fields) = match &variant.fields {
+            syn::Fields::Named(fields) => (Style::Struct, fields_ast(ctx, &fields.named)),
+            syn::Fields::Unnamed(fields) => (Style::Tuple, fields_ast(ctx, &fields.unnamed)),
+            syn::Fields::Unit => (Style::Unit, Vec::new()),
+        };
+        Variant {
+            ident: &variant.ident,
+            attrs,
+            style,
+            fields,
+            //original: variant,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
+pub enum Style {
+    Struct,
+    Tuple,
+    Unit,
+}
+
+pub enum Data<'a> {
+    Enum(Vec<Variant<'a>>),
+    Struct(Style, Vec<Field<'a>>),
+}
+
+pub struct Container<'a> {
+    pub ident: &'a syn::Ident,
+    pub attrs: attrs::Container,
+    pub data: Data<'a>,
+    pub crate_path: syn::Path,
+    pub original: &'a syn::DeriveInput,
+}
+
+impl<'a> Container<'a> {
+    pub fn from_ast(
+        ctx: &Context,
+        crate_path: syn::Path,
+        input: &'a mut syn::DeriveInput,
+    ) -> Option<Container<'a>> {
+        let attrs = attrs::Container::from_ast(ctx, &input.attrs);
+        let data = match &input.data {
+            syn::Data::Struct(s) => match &s.fields {
+                syn::Fields::Named(fields) => {
+                    Data::Struct(Style::Struct, fields_ast(ctx, &fields.named))
+                }
+                syn::Fields::Unnamed(fields) => {
+                    Data::Struct(Style::Tuple, fields_ast(ctx, &fields.unnamed))
+                }
+                syn::Fields::Unit => Data::Struct(Style::Unit, Vec::new()),
+            },
+            syn::Data::Enum(e) => {
+                let variants = e
+                    .variants
+                    .iter()
+                    .map(|variant| Variant::from_ast(ctx, variant))
+                    .collect();
+                Data::Enum(variants)
+            }
+            syn::Data::Union(u) => {
+                ctx.error_spanned(u.union_token, "Union not supported by nixrs");
+                return None;
+            }
+        };
+        Some(Container {
+            ident: &input.ident,
+            attrs,
+            data,
+            crate_path,
+            original: input,
+        })
+    }
+
+    pub fn crate_path(&self) -> &syn::Path {
+        if let Some(crate_path) = self.attrs.crate_path.as_ref() {
+            crate_path
+        } else {
+            &self.crate_path
+        }
+    }
+
+    pub fn ident_type(&self) -> syn::Type {
+        let path: syn::Path = self.ident.clone().into();
+        let tp = syn::TypePath { qself: None, path };
+        tp.into()
+    }
+}
+
+pub struct Remote<'a> {
+    pub attrs: attrs::Container,
+    pub ty: &'a syn::Type,
+    pub crate_path: syn::Path,
+}
+
+impl<'a> Remote<'a> {
+    pub fn from_ast(
+        ctx: &Context,
+        crate_path: syn::Path,
+        input: &'a inputs::RemoteInput,
+    ) -> Option<Remote<'a>> {
+        let attrs = attrs::Container::from_ast(ctx, &input.attrs);
+        if attrs.from_str.is_none() && attrs.type_from.is_none() && attrs.type_try_from.is_none() {
+            ctx.error_spanned(input, "Missing from_str, from or try_from attribute");
+            return None;
+        }
+        Some(Remote {
+            ty: &input.ident,
+            attrs,
+            crate_path,
+        })
+    }
+
+    pub fn crate_path(&self) -> &syn::Path {
+        if let Some(crate_path) = self.attrs.crate_path.as_ref() {
+            crate_path
+        } else {
+            &self.crate_path
+        }
+    }
+}
+
+fn fields_ast<'a>(ctx: &Context, fields: &'a Punctuated<syn::Field, Token![,]>) -> Vec<Field<'a>> {
+    fields
+        .iter()
+        .enumerate()
+        .map(|(idx, field)| Field::from_ast(ctx, idx, field))
+        .collect()
+}
diff --git a/tvix/nix-compat-derive/src/internal/symbol.rs b/tvix/nix-compat-derive/src/internal/symbol.rs
new file mode 100644
index 000000000000..ed3fe304eb5d
--- /dev/null
+++ b/tvix/nix-compat-derive/src/internal/symbol.rs
@@ -0,0 +1,32 @@
+use std::fmt;
+
+use syn::Path;
+
+#[derive(Copy, Clone)]
+pub struct Symbol(&'static str);
+
+pub const NIX: Symbol = Symbol("nix");
+pub const VERSION: Symbol = Symbol("version");
+pub const DEFAULT: Symbol = Symbol("default");
+pub const FROM: Symbol = Symbol("from");
+pub const TRY_FROM: Symbol = Symbol("try_from");
+pub const FROM_STR: Symbol = Symbol("from_str");
+pub const CRATE: Symbol = Symbol("crate");
+
+impl PartialEq<Symbol> for Path {
+    fn eq(&self, word: &Symbol) -> bool {
+        self.is_ident(word.0)
+    }
+}
+
+impl<'a> PartialEq<Symbol> for &'a Path {
+    fn eq(&self, word: &Symbol) -> bool {
+        self.is_ident(word.0)
+    }
+}
+
+impl fmt::Display for Symbol {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str(self.0)
+    }
+}
diff --git a/tvix/nix-compat-derive/src/lib.rs b/tvix/nix-compat-derive/src/lib.rs
new file mode 100644
index 000000000000..5c0dd5c2d480
--- /dev/null
+++ b/tvix/nix-compat-derive/src/lib.rs
@@ -0,0 +1,348 @@
+//! # Using derive
+//!
+//! 1. [Overview](#overview)
+//! 3. [Attributes](#attributes)
+//!     1. [Container attributes](#container-attributes)
+//!         1. [`#[nix(from_str)]`](#nixfrom_str)
+//!         2. [`#[nix(from = "FromType")]`](#nixfrom--fromtype)
+//!         3. [`#[nix(try_from = "FromType")]`](#nixtry_from--fromtype)
+//!         4. [`#[nix(crate = "...")]`](#nixcrate--)
+//!     2. [Variant attributes](#variant-attributes)
+//!         1. [`#[nix(version = "range")]`](#nixversion--range)
+//!     3. [Field attributes](#field-attributes)
+//!         1. [`#[nix(version = "range")]`](#nixversion--range-1)
+//!         2. [`#[nix(default)]`](#nixdefault)
+//!         3. [`#[nix(default = "path")]`](#nixdefault--path)
+//!
+//! ## Overview
+//!
+//! This crate contains derive macros and function-like macros for implementing
+//! `NixDeserialize` with less boilerplate.
+//!
+//! ### Examples
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Unnamed(u64, String);
+//! ```
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Fields {
+//!     number: u64,
+//!     message: String,
+//! };
+//! ```
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Ignored;
+//! ```
+//!
+//! ## Attributes
+//!
+//! To customize the derived trait implementations you can add
+//! [attributes](https://doc.rust-lang.org/reference/attributes.html)
+//! to containers, fields and variants.
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! #[nix(crate="nix_compat")] // <-- This is a container attribute
+//! struct Fields {
+//!     number: u64,
+//!     #[nix(version="..20")] // <-- This is a field attribute
+//!     message: String,
+//! };
+//!
+//! #[derive(NixDeserialize)]
+//! #[nix(crate="nix_compat")] // <-- This is also a container attribute
+//! enum E {
+//!     #[nix(version="..10")] // <-- This is a variant attribute
+//!     A(u64),
+//!     #[nix(version="10..")] // <-- This is also a variant attribute
+//!     B(String),
+//! }
+//! ```
+//!
+//! ### Container attributes
+//!
+//! ##### `#[nix(from_str)]`
+//!
+//! When `from_str` is specified the fields are all ignored and instead a
+//! `String` is first deserialized and then `FromStr::from_str` is used
+//! to convert this `String` to the container type.
+//!
+//! This means that the container must implement `FromStr` and the error
+//! returned from the `from_str` must implement `Display`.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! #[nix(from_str)]
+//! struct MyString(String);
+//! impl std::str::FromStr for MyString {
+//!     type Err = String;
+//!     fn from_str(s: &str) -> Result<Self, Self::Err> {
+//!         if s != "bad string" {
+//!             Ok(MyString(s.to_string()))
+//!         } else {
+//!             Err("Got a bad string".to_string())
+//!         }
+//!     }
+//! }
+//! ```
+//!
+//! ##### `#[nix(from = "FromType")]`
+//!
+//! When `from` is specified the fields are all ignored and instead a
+//! value of `FromType` is first deserialized and then `From::from` is
+//! used to convert from this value to the container type.
+//!
+//! This means that the container must implement `From<FromType>` and
+//! `FromType` must implement `NixDeserialize`.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! #[nix(from="usize")]
+//! struct MyValue(usize);
+//! impl From<usize> for MyValue {
+//!     fn from(val: usize) -> Self {
+//!         MyValue(val)
+//!     }
+//! }
+//! ```
+//!
+//! ##### `#[nix(try_from = "FromType")]`
+//!
+//! With `try_from` a value of `FromType` is first deserialized and then
+//! `TryFrom::try_from` is used to convert from this value to the container
+//! type.
+//!
+//! This means that the container must implement `TryFrom<FromType>` and
+//! `FromType` must implement `NixDeserialize`.
+//! The error returned from `try_from` also needs to implement `Display`.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! #[nix(try_from="usize")]
+//! struct WrongAnswer(usize);
+//! impl TryFrom<usize> for WrongAnswer {
+//!     type Error = String;
+//!     fn try_from(val: usize) -> Result<Self, Self::Error> {
+//!         if val != 42 {
+//!             Ok(WrongAnswer(val))
+//!         } else {
+//!             Err("Got the answer to life the universe and everything".to_string())
+//!         }
+//!     }
+//! }
+//! ```
+//!
+//! ##### `#[nix(crate = "...")]`
+//!
+//! Specify the path to the `nix-compat` crate instance to use when referring
+//! to the API in the generated code. This is usually not needed.
+//!
+//! ### Variant attributes
+//!
+//! ##### `#[nix(version = "range")]`
+//!
+//! Specifies the protocol version range where this variant is used.
+//! When deriving an enum the `version` attribute is used to select which
+//! variant of the enum to deserialize. The range is for minor version and
+//! the version ranges of all variants combined must cover all versions
+//! without any overlap or the first variant that matches is selected.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #[derive(NixDeserialize)]
+//! enum Testing {
+//!     #[nix(version="..=18")]
+//!     OldVersion(u64),
+//!     #[nix(version="19..")]
+//!     NewVersion(String),
+//! }
+//! ```
+//!
+//! ### Field attributes
+//!
+//! ##### `#[nix(version = "range")]`
+//!
+//! Specifies the protocol version range where this field is included.
+//! The range is for minor version. For example `version = "..20"`
+//! includes the field in protocol versions `1.0` to `1.19` and skips
+//! it in version `1.20` and above.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Field {
+//!     number: u64,
+//!     #[nix(version="..20")]
+//!     messsage: String,
+//! }
+//! ```
+//!
+//! ##### `#[nix(default)]`
+//!
+//! When a field is skipped because the active protocol version falls
+//! outside the range specified in [`#[nix(version = "range")]`](#nixversion--range-1)
+//! this attribute indicates that `Default::default()` should be used
+//! to get a value for the field. This is also the default
+//! when you only specify [`#[nix(version = "range")]`](#nixversion--range-1).
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Field {
+//!     number: u64,
+//!     #[nix(version="..20", default)]
+//!     messsage: String,
+//! }
+//! ```
+//!
+//! ##### `#[nix(default = "path")]`
+//!
+//! When a field is skipped because the active protocol version falls
+//! outside the range specified in [`#[nix(version = "range")]`](#nixversion--range-1)
+//! this attribute indicates that the function in `path` should be called to
+//! get a default value for the field. The given function must be callable
+//! as `fn() -> T`.
+//! For example `default = "my_value"` would call `my_value()` and `default =
+//! "AType::empty"` would call `AType::empty()`.
+//!
+//! ###### Example
+//!
+//! ```rust
+//! # use nix_compat_derive::NixDeserialize;
+//! #
+//! #[derive(NixDeserialize)]
+//! struct Field {
+//!     number: u64,
+//!     #[nix(version="..20", default="missing_string")]
+//!     messsage: String,
+//! }
+//!
+//! fn missing_string() -> String {
+//!     "missing string".to_string()
+//! }
+//! ```
+
+use internal::inputs::RemoteInput;
+use proc_macro::TokenStream;
+use syn::{parse_quote, DeriveInput};
+
+mod de;
+mod internal;
+
+#[cfg(not(feature = "external"))]
+#[proc_macro_derive(NixDeserialize, attributes(nix))]
+pub fn derive_nix_deserialize(item: TokenStream) -> TokenStream {
+    let mut input = syn::parse_macro_input!(item as DeriveInput);
+    let nnixrs: syn::Path = parse_quote!(crate);
+    de::expand_nix_deserialize(nnixrs, &mut input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}
+
+#[cfg(feature = "external")]
+#[proc_macro_derive(NixDeserialize, attributes(nix))]
+pub fn derive_nix_deserialize(item: TokenStream) -> TokenStream {
+    let mut input = syn::parse_macro_input!(item as DeriveInput);
+    let nnixrs: syn::Path = parse_quote!(::nix_compat);
+    de::expand_nix_deserialize(nnixrs, &mut input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}
+
+/// Macro to implement `NixDeserialize` on a type.
+/// Sometimes you can't use the deriver to implement `NixDeserialize`
+/// (like when dealing with types in Rust standard library) but don't want
+/// to implement it yourself. So this macro can be used for those situations
+/// where you would derive using `#[nix(from_str)]`,
+/// `#[nix(from = "FromType")]` or `#[nix(try_from = "FromType")]` if you
+/// could.
+///
+/// #### Example
+///
+/// ```rust
+/// # use nix_compat_derive::nix_deserialize_remote;
+/// #
+/// struct MyU64(u64);
+///
+/// impl From<u64> for MyU64 {
+///     fn from(value: u64) -> Self {
+///         Self(value)
+///     }
+/// }
+///
+/// nix_deserialize_remote!(#[nix(from="u64")] MyU64);
+/// ```
+#[cfg(not(feature = "external"))]
+#[proc_macro]
+pub fn nix_deserialize_remote(item: TokenStream) -> TokenStream {
+    let input = syn::parse_macro_input!(item as RemoteInput);
+    let crate_path = parse_quote!(crate);
+    de::expand_nix_deserialize_remote(crate_path, &input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}
+
+/// Macro to implement `NixDeserialize` on a type.
+/// Sometimes you can't use the deriver to implement `NixDeserialize`
+/// (like when dealing with types in Rust standard library) but don't want
+/// to implement it yourself. So this macro can be used for those situations
+/// where you would derive using `#[nix(from_str)]`,
+/// `#[nix(from = "FromType")]` or `#[nix(try_from = "FromType")]` if you
+/// could.
+///
+/// #### Example
+///
+/// ```rust
+/// # use nix_compat_derive::nix_deserialize_remote;
+/// #
+/// struct MyU64(u64);
+///
+/// impl From<u64> for MyU64 {
+///     fn from(value: u64) -> Self {
+///         Self(value)
+///     }
+/// }
+///
+/// nix_deserialize_remote!(#[nix(from="u64")] MyU64);
+/// ```
+#[cfg(feature = "external")]
+#[proc_macro]
+pub fn nix_deserialize_remote(item: TokenStream) -> TokenStream {
+    let input = syn::parse_macro_input!(item as RemoteInput);
+    let crate_path = parse_quote!(::nix_compat);
+    de::expand_nix_deserialize_remote(crate_path, &input)
+        .unwrap_or_else(syn::Error::into_compile_error)
+        .into()
+}
diff --git a/tvix/nix-compat/Cargo.toml b/tvix/nix-compat/Cargo.toml
index 9f43bb24efcc..87e9b1e6760c 100644
--- a/tvix/nix-compat/Cargo.toml
+++ b/tvix/nix-compat/Cargo.toml
@@ -8,9 +8,10 @@ edition = "2021"
 async = ["tokio"]
 # code emitting low-level packets used in the daemon protocol.
 wire = ["tokio", "pin-project-lite", "bytes"]
+test = []
 
 # Enable all features by default.
-default = ["async", "wire"]
+default = ["async", "wire", "nix-compat-derive"]
 
 [dependencies]
 bitflags = "2.4.1"
@@ -33,6 +34,11 @@ tracing = "0.1.37"
 optional = true
 version = "1.6.1"
 
+[dependencies.nix-compat-derive]
+path = "../nix-compat-derive"
+optional = true
+default-features = false
+
 [dependencies.tokio]
 optional = true
 version = "1.32.0"
diff --git a/tvix/nix-compat/src/nix_daemon/protocol_version.rs b/tvix/nix-compat/src/nix_daemon/protocol_version.rs
index 3c8fe663e867..19da28d484dd 100644
--- a/tvix/nix-compat/src/nix_daemon/protocol_version.rs
+++ b/tvix/nix-compat/src/nix_daemon/protocol_version.rs
@@ -54,6 +54,13 @@ impl From<u16> for ProtocolVersion {
     }
 }
 
+#[cfg(any(test, feature = "test"))]
+impl From<(u8, u8)> for ProtocolVersion {
+    fn from((major, minor): (u8, u8)) -> Self {
+        Self::from_parts(major, minor)
+    }
+}
+
 impl TryFrom<u64> for ProtocolVersion {
     type Error = &'static str;