deer: implement Deserialize for core::cell (#2376)

* feat: init cell

* feat: pull in code from #1875

* feat: test cells

* test: unsafe variants

* test: reflection passthrough

* fix: lint

* Update test_impls_core_cell.rs

libs/deer/desert/src/assert.rs

@@ -10,16 +10,31 @@ use crate::{deserializer::Deserializer, error::ErrorVec, token::Token};
 /// # Panics
 ///
 /// if there are any remaining tokens in the stream after deserialization
-pub fn assert_tokens_with_context<'de, T>(expected: &T, tokens: &'de [Token], context: &Context)
-where
-    T: Deserialize<'de> + PartialEq + Debug,
+pub fn assert_tokens_deserialize<'de, T>(
+    tokens: &'de [Token],
+    context: &Context,
+    assertion: impl FnOnce(T),
+) where
+    T: Deserialize<'de>,
 {
     let mut de = Deserializer::new(tokens, context);
     let received = T::deserialize(&mut de).expect("should deserialize");
 
     assert_eq!(de.remaining(), 0, "{} remaining tokens", de.remaining());
 
-    assert_eq!(received, *expected);
+    assertion(received);
+}
+
+/// # Panics
+///
+/// if there are any remaining tokens in the stream after deserialization
+pub fn assert_tokens_with_context<'de, T>(expected: &T, tokens: &'de [Token], context: &Context)
+where
+    T: Deserialize<'de> + PartialEq + Debug,
+{
+    assert_tokens_deserialize::<T>(tokens, context, |received| {
+        assert_eq!(received, *expected);
+    });
 }
 
 pub fn assert_tokens<'de, T>(value: &T, tokens: &'de [Token])
@@ -29,6 +44,13 @@ where
     assert_tokens_with_context(value, tokens, &Context::new());
 }
 
+pub fn assert_tokens_with_assertion<'de, T>(assertion: impl FnOnce(T), tokens: &'de [Token])
+where
+    T: Deserialize<'de>,
+{
+    assert_tokens_deserialize::<T>(tokens, &Context::new(), assertion);
+}
+
 /// # Panics
 ///
 /// if error could not be serialized

libs/deer/desert/src/lib.rs

@@ -11,7 +11,7 @@ pub(crate) mod tape;
 mod token;
 
 pub use assert::{
-    assert_tokens, assert_tokens_error, assert_tokens_with_context,
-    assert_tokens_with_context_error,
+    assert_tokens, assert_tokens_deserialize, assert_tokens_error, assert_tokens_with_assertion,
+    assert_tokens_with_context, assert_tokens_with_context_error,
 };
 pub use token::Token;

libs/deer/src/impls/core.rs

@@ -1,6 +1,7 @@
 mod array;
 mod atomic;
 mod bool;
+mod cell;
 mod cmp;
 mod floating;
 mod integral;

libs/deer/src/impls/core/cell.rs

@@ -0,0 +1,47 @@
+use core::cell::{Cell, RefCell, UnsafeCell};
+#[cfg(nightly)]
+use core::cell::{OnceCell, SyncUnsafeCell};
+
+use crate::{error::DeserializeError, Deserialize, Deserializer, Document, Reflection, Schema};
+
+macro_rules! impl_cell {
+    ($(#[$attr:meta])* $cell:ident) => {
+        $(#[$attr])*
+        impl<T> Reflection for $cell<T>
+        where
+            T: Reflection,
+        {
+            fn schema(doc: &mut Document) -> Schema {
+                T::schema(doc)
+            }
+        }
+
+        $(#[$attr])*
+        impl<'de, T> Deserialize<'de> for $cell<T>
+        where
+            T: Deserialize<'de>,
+        {
+            type Reflection = T::Reflection;
+
+            fn deserialize<D: Deserializer<'de>>(
+                de: D,
+            ) -> error_stack::Result<Self, DeserializeError> {
+                T::deserialize(de).map(Self::from)
+            }
+        }
+    };
+
+    ($($(#[$attr:meta])* $cell:ident),+ $(,)?) => {
+        $(impl_cell!($(#[$attr])* $cell);)*
+    };
+}
+
+impl_cell![
+    #[cfg(nightly)]
+    OnceCell,
+    #[cfg(nightly)]
+    SyncUnsafeCell,
+    Cell,
+    RefCell,
+    UnsafeCell
+];

libs/deer/src/lib.rs

@@ -4,7 +4,8 @@
         provide_any,
         error_in_core,
         error_generic_member_access,
-        integer_atomics
+        integer_atomics,
+        sync_unsafe_cell
     )
 )]
 #![cfg_attr(not(feature = "std"), no_std)]

libs/deer/tests/test_impls_core_cell.rs

@@ -0,0 +1,107 @@
+#![cfg_attr(nightly, feature(sync_unsafe_cell))]
+use core::cell::{Cell, RefCell, UnsafeCell};
+#[cfg(nightly)]
+use core::cell::{OnceCell, SyncUnsafeCell};
+
+use deer::{Deserialize, Number};
+use deer_desert::{assert_tokens, assert_tokens_with_assertion, Token};
+use proptest::prelude::*;
+use serde::Serialize;
+use similar_asserts::assert_serde_eq;
+
+#[cfg(not(miri))]
+proptest! {
+    #[test]
+    fn cell_ok(value in any::<u8>()) {
+        let expected = Cell::new(value);
+
+        assert_tokens(&expected, &[Token::Number(Number::from(value))]);
+    }
+
+    #[test]
+    fn ref_cell_ok(value in any::<u8>()) {
+        let expected = RefCell::new(value);
+
+        assert_tokens(&expected, &[Token::Number(Number::from(value))]);
+    }
+
+    #[test]
+    fn unsafe_cell_ok(value in any::<u8>()) {
+        // need to use the underlying function, because `UnsafeCell` does not expose PartialEq
+        assert_tokens_with_assertion(|mut received: UnsafeCell<u8>| {
+            assert_eq!(*received.get_mut(), value);
+        }, &[Token::Number(
+            Number::from(value),
+        )]);
+    }
+
+
+    #[cfg(nightly)]
+    #[test]
+    fn once_cell_ok(value in any::<u8>()) {
+        let expected: OnceCell<_> = value.into();
+
+        assert_tokens(&expected, &[Token::Number(Number::from(value))]);
+    }
+
+    #[cfg(nightly)]
+    #[test]
+    fn sync_unsafe_cell_ok(value in any::<u8>()) {
+        // need to use the underlying function, because `SyncUnsafeCell` does not expose PartialEq
+        assert_tokens_with_assertion(|mut received: SyncUnsafeCell<u8>| {
+            assert_eq!(*received.get_mut(), value);
+        }, &[Token::Number(
+            Number::from(value),
+        )]);
+    }
+}
+
+fn assert_json(lhs: impl Serialize, rhs: impl Serialize) {
+    let lhs = serde_json::to_value(lhs).expect("should be able to serialize lhs");
+    let rhs = serde_json::to_value(rhs).expect("should be able to serialize rhs");
+
+    assert_serde_eq!(lhs, rhs);
+}
+
+// test that the `Reflection` of all types are the same as their underlying type
+#[test]
+fn cell_reflection_same() {
+    let lhs = Cell::<u8>::reflection();
+    let rhs = u8::reflection();
+
+    assert_json(lhs, rhs);
+}
+
+#[test]
+fn ref_cell_reflection_same() {
+    let lhs = RefCell::<u8>::reflection();
+    let rhs = u8::reflection();
+
+    assert_json(lhs, rhs);
+}
+
+#[test]
+fn unsafe_cell_reflection_same() {
+    let lhs = UnsafeCell::<u8>::reflection();
+    let rhs = u8::reflection();
+
+    assert_json(lhs, rhs);
+}
+
+#[cfg(nightly)]
+#[test]
+fn once_cell_reflection_same() {
+    let lhs = OnceCell::<u8>::reflection();
+    let rhs = u8::reflection();
+
+    assert_json(lhs, rhs);
+}
+
+#[cfg(nightly)]
+#[test]
+fn sync_unsafe_cell_reflection_same() {
+    let lhs = SyncUnsafeCell::<u8>::reflection();
+    let rhs = u8::reflection();
+
+    assert_json(lhs, rhs);
+}