feat: Implement patch for Box and Option

.github/workflows/test.yml

@@ -17,14 +17,24 @@ jobs:
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Test no defualt features
+      - name: Test no default features
         run: |
           nix develop -c cargo run --no-default-features --example instance
           nix develop -c cargo run --no-default-features --example diff
           nix develop -c cargo run --no-default-features --example json
           nix develop -c cargo run --no-default-features --example rename-patch-struct
           nix develop -c cargo run --no-default-features --example patch-attr
           nix develop -c cargo test --no-default-features
+
+      - name: Test with std features
+        run: |
+          nix develop -c cargo run --features=std --example instance
+          nix develop -c cargo run --features=std --example diff
+          nix develop -c cargo run --features=std --example json
+          nix develop -c cargo run --features=std --example rename-patch-struct
+          nix develop -c cargo run --features=std --example patch-attr
+          nix develop -c cargo run --features=std --example option
+          nix develop -c cargo test --features=std
 
       - name: Test with default features
         run: |

README.md

@@ -73,6 +73,15 @@ The [examples][examples] demo following scenarios.
 - check a patch is empty or not
 - add attribute to patch struct
 
+## Features
+
+This crate also includes the following optional features:
+- `status`: implements the `PatchStatus` trait for the patch struct, which provides the `is_empty` method.
+- `box`: implements the `Patch<Box<P>>` trait for `T` where `T` implements `Patch<P>`.
+    This let you patch a boxed (or not) struct with a boxed patch.
+- `option`: implements the `Patch<Option<P>>` trait for `Option<T>` where `T` implements `Patch<P>`.
+    `T` also needs to implement `From<P>`.
+    This let you patch structs containing fields with optional values.
 
 [crates-badge]: https://img.shields.io/crates/v/struct-patch.svg
 [crate-url]: https://crates.io/crates/struct-patch

struct-patch/Cargo.toml

@@ -20,7 +20,9 @@ serde_with = "3.9.0"
 
 [features]
 default = ["status"]
+std = ["box", "option"]
+box = []
+option = []
 status = [
     "struct-patch-derive/status"
 ]
-

struct-patch/examples/diff.rs

@@ -16,7 +16,7 @@ fn main() {
     };
 
     // Diff on two items to get the patch
-    let patch = new_item.into_patch_by_diff(item);
+    let patch: ItemPatch = new_item.into_patch_by_diff(item);
 
     assert_eq!(
         format!("{patch:?}"),

struct-patch/examples/instance.rs

@@ -20,7 +20,7 @@ struct Item {
 fn main() {
     let mut item = Item::default();
 
-    let mut patch = Item::new_empty_patch();
+    let mut patch: ItemPatch = Item::new_empty_patch();
 
     patch.field_int = Some(7);
 

struct-patch/examples/option.rs

@@ -0,0 +1,57 @@
+#[cfg(feature = "option")]
+use struct_patch::Patch;
+
+#[cfg(feature = "option")]
+fn main() {
+    #[derive(Default, Debug, PartialEq, Patch)]
+    #[patch(attribute(derive(Debug, Default)))]
+    struct User {
+        name: String,
+        #[patch(name = "Option<AddressPatch>")]
+        address: Option<Address>,
+    }
+
+    #[derive(Default, Debug, PartialEq, Patch)]
+    #[patch(attribute(derive(Debug, Default)))]
+    struct Address {
+        street: Option<String>,
+        country: String,
+    }
+
+    impl From<AddressPatch> for Address {
+        fn from(patch: AddressPatch) -> Self {
+            let mut address = Address::default();
+            address.apply(patch);
+            address
+        }
+    }
+
+    let mut user = User {
+        name: String::from("Thomas"),
+        address: None,
+    };
+    let mut patch: UserPatch = User::new_empty_patch();
+
+    patch.address = Some(Some(AddressPatch {
+        country: Some("France".to_string()),
+        ..Default::default()
+    }));
+
+    user.apply(patch);
+
+    assert_eq!(
+        user,
+        User {
+            name: String::from("Thomas"),
+            address: Some(Address {
+                street: None,
+                country: String::from("France"),
+            }),
+        }
+    );
+}
+
+#[cfg(not(feature = "option"))]
+fn main() {
+    println!("Please enable the 'option' feature to run this example");
+}

struct-patch/examples/patch-attr.rs

@@ -1,5 +1,5 @@
-use struct_patch::Patch;
 use serde_with::skip_serializing_none;
+use struct_patch::Patch;
 
 #[derive(Default, Patch)]
 #[patch(attribute(derive(serde::Serialize, Debug, Default)))]
@@ -21,7 +21,7 @@ struct Item {
 // }
 
 fn main() {
-    let patch = Item::new_empty_patch();
+    let patch: ItemPatch = Item::new_empty_patch();
 
     assert_eq!(
         format!("{patch:?}"),

struct-patch/examples/rename-patch-struct.rs

@@ -19,7 +19,7 @@ struct Item {
 // }
 
 fn main() {
-    let patch = Item::new_empty_patch();
+    let patch: ItemOverlay = Item::new_empty_patch();
 
     assert_eq!(
         format!("{patch:?}"),

struct-patch/examples/status.rs

@@ -11,7 +11,7 @@ struct Item {
 }
 
 fn main() {
-    let mut patch = Item::new_empty_patch();
+    let mut patch: ItemPatch = Item::new_empty_patch();
 
     #[cfg(feature = "status")]
     assert!(patch.is_empty()); // provided by PatchStatus

struct-patch/src/lib.rs

@@ -43,10 +43,12 @@
 //! ```
 //!
 //! More details on how to use the the derive macro, including what attributes are available, are available under [`Patch`]
-#![cfg_attr(not(test), no_std)]
+#![cfg_attr(not(any(test, feature = "box", feature = "option")), no_std)]
 
 #[doc(hidden)]
 pub use struct_patch_derive::Patch;
+#[cfg(any(feature = "box", feature = "option"))]
+pub mod std;
 pub mod traits;
 pub use traits::*;