Handle merge feature only (#95)

* add test merge feature without op

* fix merge feature dependency

* bounce version

Author: yanganto

.github/workflows/test.yml

@@ -43,6 +43,7 @@ jobs:
         run: |
           nix develop -c cargo run --features=option --features=merge --example option
           nix develop -c cargo run --features=merge --example op
+          nix develop -c cargo test --features=merge --no-default-features
           nix develop -c cargo test --features=merge
 
       - name: Test with option features

Cargo.toml

@@ -7,7 +7,7 @@ members = [
 
 [workspace.package]
 authors = ["Antonio Yang <[email protected]>"]
-version = "0.9.3"
+version = "0.9.4"
 edition = "2021"
 categories = ["development-tools"]
 keywords = ["struct", "patch", "macro", "derive", "overlay"]

README.md

@@ -133,7 +133,7 @@ This crate also includes the following optional features:
 - `status`(default): implements the `Status` trait for the patch struct, which provides the `is_empty` method.
 - `op` (default): provide operators `<<` between instance and patch, and `+` for patches
   - default: when there is a field conflict between patches, `+` will add together if the `#[patch(addable)]` or `#[patch(add=fn)]` is provided, else it will panic.
-  - `merge` (optional): implements the `Merge` trait for the patch struct, which provides the `merge` method, and `<<` between patches.
+- `merge` (optional): implements the `Merge` trait for the patch struct, which provides the `merge` method, and `<<` (if `op` feature enabled) between patches.
 - `std`(optional):
   - `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.

struct-patch-derive/src/patch.rs

@@ -187,7 +187,7 @@ impl Patch {
             }
         };
 
-        #[cfg(feature = "merge")]
+        #[cfg(all(feature = "op", feature = "merge"))]
         let op_impl = quote! {
             impl #generics core::ops::Shl<#name #generics> for #struct_name #generics #where_clause {
                 type Output = Self;

struct-patch/Cargo.toml

@@ -11,7 +11,7 @@ license.workspace = true
 readme.workspace = true
 
 [dependencies]
-struct-patch-derive = { version = "=0.9.3", path = "../struct-patch-derive" }
+struct-patch-derive = { version = "=0.9.4", path = "../struct-patch-derive" }
 
 [dev-dependencies]
 serde_json = "1.0"