feat: add optional jiff 0.2 shape support (#19)

Author: tisonkun

.github/workflows/ci.yml

@@ -103,6 +103,7 @@ jobs:
       - name: Check no_std
         run: |
           cargo check -p serde-shape --lib --no-default-features --target thumbv7em-none-eabihf
+          cargo check -p serde-shape --lib --no-default-features --features jiff02 --target thumbv7em-none-eabihf
           cargo check -p serde-shape-test-no-std --lib --target thumbv7em-none-eabihf
         shell: bash
 

Cargo.lock

@@ -188,6 +188,7 @@ Types that branch on `Serializer::is_human_readable()` or `Deserializer::is_huma
 `serde-shape` enables no features by default.
 
 - `derive`: enables `#[derive(SerializeShape)]` and `#[derive(DeserializeShape)]`.
+- `jiff02`: enables string shapes for Jiff 0.2 types with direct Serde implementations.
 - `std`: enables shape implementations for standard-library-only types.
 
 ## Built-in shapes
@@ -205,6 +206,8 @@ The built-in implementations follow Serde's semantic representations in each dir
 | Network       | `core::net` IP and socket address types                                                                                                                                            |
 | `std` feature | Atomics available on the target, `HashMap`, `HashSet`, `Path`, `PathBuf`, `Mutex`, and `RwLock`                                                                                    |
 
+With the `jiff02` feature, `Date`, `DateTime`, `ISOWeekDate`, `SignedDuration`, `Span`, `Time`, `Timestamp`, and `Zoned` are string shapes in both directions, matching Jiff's direct Serde implementations.
+
 Network address shapes are unions of their human-readable string representation and their compact Serde representation. A serialized byte slice and an owned `Box<[u8]>` input are sequences, while borrowed byte deserialization uses `ShapeRef::Bytes`.
 
 OS string shapes preserve Serde's target-specific externally tagged representation: `Unix` contains a byte sequence, while `Windows` contains a `u16` sequence. Deserialization advertises only the variant accepted on the current target.

README.md

@@ -35,9 +35,11 @@ rustdoc-args = ["--cfg", "docsrs"]
 [features]
 default = []
 derive = ["dep:serde-shape-derive"]
+jiff02 = ["dep:jiff02"]
 std = []
 
 [dependencies]
+jiff02 = { package = "jiff", version = "0.2", default-features = false, optional = true }
 serde-shape-derive = { workspace = true, optional = true }
 
 [lints]

serde-shape/Cargo.toml

@@ -0,0 +1,57 @@
+// Copyright 2026 FastLabs Developers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use jiff02::SignedDuration;
+use jiff02::Span;
+use jiff02::Timestamp;
+use jiff02::Zoned;
+use jiff02::civil::Date;
+use jiff02::civil::DateTime;
+use jiff02::civil::ISOWeekDate;
+use jiff02::civil::Time;
+
+use crate::DeserializeShape;
+use crate::DeserializeShapeContext;
+use crate::SerializeShape;
+use crate::SerializeShapeContext;
+use crate::ShapeRef;
+
+macro_rules! string_shape {
+    ($($ty:ty),* $(,)?) => {
+        $(
+            impl SerializeShape for $ty {
+                fn serialize_shape_in(_context: &mut SerializeShapeContext) -> ShapeRef {
+                    ShapeRef::String
+                }
+            }
+
+            impl DeserializeShape for $ty {
+                fn deserialize_shape_in(_context: &mut DeserializeShapeContext) -> ShapeRef {
+                    ShapeRef::String
+                }
+            }
+        )*
+    };
+}
+
+string_shape!(
+    Date,
+    DateTime,
+    ISOWeekDate,
+    SignedDuration,
+    Span,
+    Time,
+    Timestamp,
+    Zoned,
+);

serde-shape/src/impls/jiff02.rs

@@ -15,6 +15,8 @@
 mod bound;
 mod container;
 mod ffi;
+#[cfg(feature = "jiff02")]
+mod jiff02;
 mod net;
 #[cfg(all(feature = "std", any(unix, windows)))]
 mod os_string;

serde-shape/src/impls/mod.rs

@@ -645,3 +645,30 @@ fn maps_network_shapes_without_std() {
         FieldWireShape::Value(ShapeRef::Tuple(vec![ipv4_binary, ShapeRef::U16]))
     );
 }
+
+#[cfg(feature = "jiff02")]
+#[test]
+fn maps_jiff_serde_types_to_strings() {
+    fn assert_string_shapes<T>()
+    where
+        T: DeserializeShape + SerializeShape,
+    {
+        assert_eq!(
+            DeserializeShapeGraph::for_type::<T>().root(),
+            &ShapeRef::String
+        );
+        assert_eq!(
+            SerializeShapeGraph::for_type::<T>().root(),
+            &ShapeRef::String
+        );
+    }
+
+    assert_string_shapes::<jiff02::civil::Date>();
+    assert_string_shapes::<jiff02::civil::DateTime>();
+    assert_string_shapes::<jiff02::civil::ISOWeekDate>();
+    assert_string_shapes::<jiff02::civil::Time>();
+    assert_string_shapes::<jiff02::SignedDuration>();
+    assert_string_shapes::<jiff02::Span>();
+    assert_string_shapes::<jiff02::Timestamp>();
+    assert_string_shapes::<jiff02::Zoned>();
+}

serde-shape/src/tests.rs

@@ -87,6 +87,7 @@ impl CommandTest {
         run_command(make_test_cmd(self.no_capture, "serde-shape", &[]));
         run_command(make_test_cmd(self.no_capture, "serde-shape", &["std"]));
         run_command(make_test_cmd(self.no_capture, "serde-shape", &["derive"]));
+        run_command(make_test_cmd(self.no_capture, "serde-shape", &["jiff02"]));
         run_command(make_test_cmd(
             self.no_capture,
             "serde-shape",