Replace allow attributes with expect

[leynos]

Summary

• remove allow(dead_code) from EmptyPreamble test helper
• remove allow(dead_code) from metadata routing example

Testing

• RUSTUP_TOOLCHAIN=nightly-2025-07-22 make fmt
• RUSTUP_TOOLCHAIN=nightly-2025-07-22 make lint
• RUSTUP_TOOLCHAIN=nightly-2025-07-22 make test

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https://chatgpt.com/codex/tasks/task_e_688d53c16fa48322a6078931d3eac25a

Summary by Sourcery

Enhancements:

• Replace allow(dead_code) attributes with expect(dead_code) including rationale in example and test helper structs

[sourcery-ai]

Reviewer's Guide

This PR refactors lint attributes by replacing allow(dead_code) with expect(dead_code, reason=…) on demonstration and test-only structs to provide explicit rationale for unused code.

Class diagram for updated test and example structs with expect attribute

classDiagram
    class EmptyPreamble {
        <<test helper>>
        +Debug
        +Clone
        +PartialEq
        +Encode
        +Decode
        <<expect(dead_code, reason = "used only in doctest to illustrate an empty preamble")>>
    }
    class Pong {
        <<example struct>>
        +bincode::Decode
        +bincode::Encode
        <<expect(dead_code, reason = "placeholder for demonstration of metadata routing")>>
    }

Loading

File-Level Changes

Change	Details	Files
Swapped allow(dead_code) for expect(dead_code) on the example demo struct	Removed #[allow(dead_code)] from struct Pong Added #[expect(dead_code, reason = "placeholder for demonstration of metadata routing")]	examples/metadata_routing.rs
Swapped allow(dead_code) for expect(dead_code) on the test helper struct	Removed #[allow(dead_code)] from struct EmptyPreamble Added #[expect(dead_code, reason = "used only in doctest to illustrate an empty preamble")]	src/server.rs

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[coderabbitai]

Summary by CodeRabbit

• Style
  • Updated internal code annotations to clarify intentional unused code for demonstration and documentation purposes. No changes to functionality or user-facing features.

Walkthrough

Update lint attributes from #[allow(dead_code)] to #[expect(dead_code, reason = "...")] on demonstration structs in both the example and test code. These changes clarify the intent behind unused code by providing explicit reasons for their presence.

Changes

Cohort / File(s)	Change Summary
Example metadata routing lint attribute examples/metadata_routing.rs	Replace #[allow(dead_code)] with #[expect(dead_code, reason = "placeholder for demonstration of metadata routing")] on the Pong struct.
Server test lint attribute src/server.rs	Replace #[allow(dead_code)] with #[expect(dead_code, reason = "used only in doctest to illustrate an empty preamble")] on the EmptyPreamble struct in the test module.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

Linting with reason, a tidy affair,
No more dead code warnings floating in air.
With expect and purpose, intentions are shown,
Each placeholder struct is now clearly known.
Cheers to the code, explicit and neat—
Dead code with reason is hard to beat!

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: ASSERTIVE
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5b4448a and 4566cf3.

📒 Files selected for processing (2)

• examples/metadata_routing.rs (1 hunks)
• src/server.rs (1 hunks)

🧰 Additional context used

📓 Path-based instructions (1)

**/*.rs

📄 CodeRabbit Inference Engine (AGENTS.md)

**/*.rs: Clippy warnings MUST be disallowed.
Fix any warnings emitted during tests in the code itself rather than silencing them.
Where a function is too long, extract meaningfully named helper functions adhering to separation of concerns and CQRS.
Where a function has too many parameters, group related parameters in meaningfully named structs.
Where a function is returning a large error consider using Arc to reduce the amount of data returned.
Every module must begin with a module level (//!) comment explaining the module's purpose and utility.
Document public APIs using Rustdoc comments (///) so documentation can be generated with cargo doc.
Prefer immutable data and avoid unnecessary mut bindings.
Handle errors with the Result type instead of panicking where feasible.
Avoid unsafe code unless absolutely necessary and document any usage clearly.
Place function attributes after doc comments.
Do not use return in single-line functions.
Use predicate functions for conditional criteria with more than two branches.
Lints must not be silenced except as a last resort.
Lint rule suppressions must be tightly scoped and include a clear reason.
Prefer expect over allow.
Prefer .expect() over .unwrap().
Use concat!() to combine long string literals rather than escaping newlines with a backslash.
Prefer semantic error enums: Derive std::error::Error (via the thiserror crate) for any condition the caller might inspect, retry, or map to an HTTP status.
Use an opaque error only at the app boundary: Use eyre::Report for human-readable logs; these should not be exposed in public APIs.
Never export the opaque type from a library: Convert to domain enums at API boundaries, and to eyre only in the main main() entrypoint or top-level async task.

Files:

• src/server.rs
• examples/metadata_routing.rs

---

⚙️ CodeRabbit Configuration File

**/*.rs: * Seek to keep the cyclomatic complexity of functions no more than 12.

• Adhere to single responsibility and CQRS

• Place function attributes after doc comments.

• Do not use return in single-line functions.

• Move conditionals with >2 branches into a predicate function.

• Avoid unsafe unless absolutely necessary.

• Every module must begin with a //! doc comment that explains the module's purpose and utility.

• Comments and docs must follow en-GB-oxendict (-ize / -our) spelling and grammar

• Lints must not be silenced except as a last resort.

  • #[allow] is forbidden.
  • Only narrowly scoped #[expect(lint, reason = "...")] is allowed.
  • No lint groups, no blanket or file-wide suppression.
  • Include FIXME: with link if a fix is expected.

• Use rstest fixtures for shared setup and to avoid repetition between tests.

• Replace duplicated tests with #[rstest(...)] parameterised cases.

• Prefer mockall for mocks/stubs.

• Prefer .expect() over .unwrap()

• Ensure that any API or behavioural changes are reflected in the documentation in docs/

• Ensure that any completed roadmap steps are recorded in the appropriate roadmap in docs/

• Files must not exceed 400 lines in length

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Files:

• src/server.rs
• examples/metadata_routing.rs

⏰ Context from checks skipped due to timeout of 240000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: build-test

🔇 Additional comments (2)

src/server.rs (1)

561-564: Maintain use of #[expect(dead_code)] with explicit reason

The previous blanket suppression is gone and the new scoped expectation includes a clear rationale, aligning with the house lint policy. Good placement directly on the struct keeps the scope tight.

examples/metadata_routing.rs (1)

63-66: Retain #[expect(dead_code)] for the demo struct

The switch from allow to expect plus a descriptive reason satisfies the no-blanket-suppression rule while documenting intent. No further action required.

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[sourcery-ai]

Hey @leynos - I've reviewed your changes and they look great!

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