ariesdevil opened a new pull request, #3073: URL: https://github.com/apache/fory/pull/3073
<!-- **Thanks for contributing to Apache Fory™.** **If this is your first time opening a PR on fory, you can refer to [CONTRIBUTING.md](https://github.com/apache/fory/blob/main/CONTRIBUTING.md).** Contribution Checklist - The **Apache Fory™** community has requirements on the naming of pr titles. You can also find instructions in [CONTRIBUTING.md](https://github.com/apache/fory/blob/main/CONTRIBUTING.md). - Apache Fory™ has a strong focus on performance. If the PR you submit will have an impact on performance, please benchmark it first and provide the benchmark result here. --> ## Why? When using `#[derive(ForyObject)]` on a struct that already has a manual `impl Default`, a compilation error occurs due to conflicting `Default` implementations. The `ForyObject` derive macro automatically generates `impl Default`, which conflicts with user-provided implementations. This is a common scenario when integrating Fory with existing codebases (e.g., OpenRaft) where types already have custom `Default` implementations with specific default values. ## What does this PR do? Adds a `#[fory(skip_default)]` attribute to the `ForyObject` derive macro that: 1. Skips generating `impl std::default::Default` for the annotated type 2. Only generates `impl ForyDefault` that delegates to the existing `Default::default()` ### Usage #[derive(ForyObject)] #[fory(skip_default)] // Don't generate impl Default struct BasicNode { addr: String, } // User's own Default implementation is preserved impl Default for BasicNode { fn default() -> Self { Self { addr: "localhost".to_string() } } } ### Why not detect manual `impl Default` automatically? Rust's proc_macro system only has access to the token stream of the type being derived. It cannot see other `impl` blocks in the same file or elsewhere. The existing `has_existing_default()` function can only detect `#[derive(Default)]`, not manual `impl Default` blocks. This is a fundamental limitation of proc_macros, not a code issue. ## Related issues None ## Does this PR introduce any user-facing change? - [x] Does this PR introduce any public API change? - Adds new optional attribute `#[fory(skip_default)]` to the `ForyObject` derive macro - [ ] Does this PR introduce any binary protocol compatibility change? ## Benchmark This change only affects code generation at compile time and has no runtime performance impact. <!-- When the PR has an impact on performance (if you don't know whether the PR will have an impact on performance, you can submit the PR first, and if it will have impact on performance, the code reviewer will explain it), be sure to attach a benchmark data here. Delete section if not applicable. --> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
