Allow patch + patch if no conflict

yanganto · Aug 12, 2024 · a7835b3 · a7835b3
1 parent c0d3ff5
commit a7835b3
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Showing 3 changed files with 46 additions and 44 deletions.
diff --git a/README.md b/README.md
@@ -38,6 +38,17 @@ fn patch_json() {
     let patch: ItemPatch = serde_json::from_str(data).unwrap();
 
     item.apply(patch);
+    // You can do 
+    // `let new_item = item << patch;`
+
+    // For multiple patches,
+    // you can do this
+    // `let new_item = item << patch_1 << patch_2;`
+    // or make an aggregated one, but please make sure the patch fields do not conflict, else will panic
+    // ```
+    // let overall_patch = patch_1 + patch_2 + patch_3;
+    // let new_item = item << overall_patch;
+    // ```
 
     assert_eq!(
         item,

diff --git a/struct-patch-derive/src/lib.rs b/struct-patch-derive/src/lib.rs
@@ -125,45 +125,28 @@ impl Patch {
                 }
             }
 
-            // TODO
-            // We need unstable feature to make sure the type of field for add feature
-            // https://doc.rust-lang.org/std/any/fn.type_name_of_val.html
-            // impl #generics core::ops::Add<Self> for #name #generics #where_clause {
-            //     type Output = Self;
-
-            //     fn add(mut self, rhs: Self) -> Self {
-            //         Self {
-            //             #(
-            //                 #renamed_field_names: match (self.#renamed_field_names, rhs.#renamed_field_names) {
-            //                     (Some(a), Some(b)) => {
-            //                         if std::any::type_name_of_val(&a) == "usize" {
-            //                             Some(a + b)
-            //                         } else {
-            //                             Some(b)
-            //                         }
-            //                     },
-            //                     (Some(a), None) => Some(a),
-            //                     (None, Some(b)) => Some(b),
-            //                     (None, None) => None,
-            //                 },
-            //             )*
-            //             #(
-            //                 #original_field_names: match (self.#original_field_names, rhs.#original_field_names) {
-            //                     (Some(a), Some(b)) => {
-            //                         if std::any::type_name_of_val(&a) == "usize" {
-            //                             Some(a + b)
-            //                         } else {
-            //                             Some(b)
-            //                         }
-            //                     },
-            //                     (Some(a), None) => Some(a),
-            //                     (None, Some(b)) => Some(b),
-            //                     (None, None) => None,
-            //                 },
-            //             )*
-            //         }
-            //     }
-            // }
+            impl #generics core::ops::Add<Self> for #name #generics #where_clause {
+                type Output = Self;
+
+                fn add(mut self, rhs: Self) -> Self {
+                    Self {
+                        #(
+                            #renamed_field_names: match (self.#renamed_field_names, rhs.#renamed_field_names) {
+                                (Some(a), Some(b)) => {
+                                    // TODO handle #[patch(addable)] fields
+                                    panic!("There are conflict patches in {}", stringify!(#renamed_field_names))
+                                },
+                                (Some(a), None) => Some(a),
+                                (None, Some(b)) => Some(b),
+                                (None, None) => None,
+                            },
+                        )*
+                        #(
+                            #original_field_names: rhs.#original_field_names.or(self.#original_field_names),
+                        )*
+                    }
+                }
+            }
         };
 
         let patch_impl = quote! {

diff --git a/struct-patch/examples/op.rs b/struct-patch/examples/op.rs
@@ -27,6 +27,12 @@ fn main() {
     assert_eq!(item.field_string, "");
 
     let another_patch = ItemPatch {
+        field_complete: None,
+        field_int: None,
+        field_string: Some("from another patch".into()),
+    };
+
+    let _conflict_patch = ItemPatch {
         field_complete: None,
         field_int: Some(1),
         field_string: Some("from another patch".into()),
@@ -38,11 +44,13 @@ fn main() {
         field_string: None,
     };
 
-    // TODO
-    // We need unstable feature to make sure the type of field for add feature
-    // https://doc.rust-lang.org/std/any/fn.type_name_of_val.html#
-    // let final_item_from_merge = item.clone() << (another_patch.clone() + the_other_patch.clone());
-    // assert_eq!(final_item_from_merge.field_int, 3);
+    // let final_item_from_merge = item.clone() << (_conflict_patch + the_other_patch.clone());
+    // Will get panic `There are conflict patches in field_int`
+    // Will be handdled as the discussion
+    // https://github.com/yanganto/struct-patch/pull/32#issuecomment-2283154990
+
+    let final_item_from_merge = item.clone() << (another_patch.clone() + the_other_patch.clone());
+    assert_eq!(final_item_from_merge.field_int, 2);
 
     let final_item_series_patch = item << another_patch << the_other_patch;
     assert_eq!(final_item_series_patch.field_int, 2);