fix(backend): resolve clippy lints

[kyscott18]

Resolves all 8 clippy findings surfaced by the new rust CI job (#100) so cargo clippy -D warnings passes.

Mechanical fixes (equivalents of cargo clippy --fix)

File	Lint	Fix
server.rs	needless_return	drop return
server.rs	match_like_matches_macro	use matches!
event_filter.rs	ptr_arg	&Vec<T> → &[T]
event_filter.rs	needless_borrow	drop &
event_listener.rs	manual_is_multiple_of	.is_multiple_of(100)
serializable_event.rs	clone_on_copy	drop .clone() on u64

Manual fixes (not auto-fixable)

File	Lint	Fix
server.rs	large_enum_variant	box the 640-byte variant: EventDataOrMetrics::Event(Box<EventData>); the from(&event_data) call site deref-coerces, construction now uses Box::new(..)
event_listener.rs	should_implement_trait	rename inherent EventName::from_str → from_name (+ its single caller) so it no longer shadows std::str::FromStr::from_str

No behavioral change. With these, the rust job (fmt + clippy -D warnings + build) should be fully green.

Stacked on #100 (the unified CI workflow) so the containerized rust job validates these fixes. Rebase base back to main once #100 merges.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
monode	Ready	Preview, Comment	Jun 9, 2026 7:37pm

[greptile-apps]

Greptile Summary

This PR resolves all 8 Clippy warnings surfaced by the new rust CI job, making cargo clippy -D warnings pass. All changes are mechanical — no behavioral difference.

• Mechanical fixes: drops redundant return, clone(), and & borrows; upgrades &Vec<T> to &[T]; replaces an if-let chain with matches!; and uses is_multiple_of(100) in the event loop.
• EventDataOrMetrics::Event is now Box<EventData> to address the large_enum_variant lint, with the single construction site updated to Box::new(event_data) and the match arm updated to &*event_data for deref-coercion.
• EventName::from_str → from_name avoids shadowing std::str::FromStr::from_str; the single internal call site in event_to_data is updated accordingly. A small undocumented client.rs change also removes redundant as u64 casts that the PR description doesn't mention.

Confidence Score: 5/5

All changes are mechanical Clippy lint fixes with no behavioral change; safe to merge once the stacking dependency on #100 lands.

Every fix is a direct, correct application of what Clippy prescribes — boxing the large enum variant, removing redundant borrows/casts/clones, using idiomatic matches!. The one unrelated undocumented client.rs change is also provably a no-op (removing an identity as u64 cast). No logic paths are altered.

No files require special attention; the client.rs change is safe but is worth a brief mention since it was omitted from the PR description.

Important Files Changed

Filename	Overview
backend/src/lib/server.rs	Boxes the large EventData variant, removes redundant return, and replaces if-let chain with matches! — all correct and no behavioral change.
backend/src/lib/event_listener.rs	Renames from_str → from_name (single call site updated) and replaces % 100 == 0 with .is_multiple_of(100); both are correct mechanical changes.
backend/src/lib/event_filter.rs	Replaces &Vec<T> with &[T] in ArrayPrefixFilter::matches and removes the redundant borrow in the is_native_transfer call; both are idiomatic improvements with no semantic change.
backend/src/lib/serializable_event.rs	Drops .clone() on the u64 field timestamp_ns — trivially correct since u64 is Copy.
backend/src/bin/client.rs	Removes redundant as u64 casts from u64 - u64 subtractions; safe since both operands and Duration::from_nanos already operate on u64, but this change is not described in the PR.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[ExecEventRing / Snapshot] -->|event descriptor| B[event_to_data]
    B -->|EventName::from_name| C{known event?}
    C -->|None| D[skip event]
    C -->|Some EventData| E[run_event_forwarder_task]
    E -->|Box::new event_data| F[broadcast::Sender EventDataOrMetrics]
    F -->|EventDataOrMetrics::Event Box EventData| G[process_event]
    G -->|&*event_data| H[SerializableEventData::from]
    H --> I{filter.matches_event?}
    I -->|yes| J[events_buf push]
    I -->|no| K[discard]
    J --> L[client_write_task send over WebSocket]

Loading

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
backend/src/bin/client.rs:113-123
**Undocumented change not listed in PR description**

Two `as u64` casts are removed here (`event.timestamp_ns - txn_start_ns` and `event.timestamp_ns - client_state.block_start_ns`). Both operands are already `u64`, so the cast was a no-op and the removal is correct, but neither change appears in the PR's list of 8 lint fixes. Looks like a `clippy::unnecessary_cast` fix that slipped in — worth noting for completeness.

_{Reviews (4): Last reviewed commit: "fix(backend): remove redundant u64 casts..." | Re-trigger Greptile}

[greptile-apps]

is_multiple_of requires Rust ≥ 1.87.0

<uN>::is_multiple_of was stabilized in Rust 1.87.0 (May 2025). The CI container pins rust:1.91-slim so the build will pass, but Cargo.toml has no rust-version field. Any contributor running cargo build or cargo clippy locally with a stable toolchain older than 1.87 will hit a compile error with no obvious hint about the minimum required version. Adding rust-version = "1.87" to Cargo.toml lets cargo surface a clear diagnostic instead of a confusing "method not found" error.

Prompt To Fix With AI

This is a comment left during a code review.
Path: backend/src/lib/event_listener.rs
Line: 287

Comment:
**`is_multiple_of` requires Rust ≥ 1.87.0**

`<uN>::is_multiple_of` was stabilized in Rust 1.87.0 (May 2025). The CI container pins `rust:1.91-slim` so the build will pass, but `Cargo.toml` has no `rust-version` field. Any contributor running `cargo build` or `cargo clippy` locally with a stable toolchain older than 1.87 will hit a compile error with no obvious hint about the minimum required version. Adding `rust-version = "1.87"` to `Cargo.toml` lets `cargo` surface a clear diagnostic instead of a confusing "method not found" error.

How can I resolve this? If you propose a fix, please make it concise.