fix: resolve Clippy errors from Rust 1.97 lint promotions

[thomasmaas]

Summary

• Replace for (_, v) in map.iter() with for v in map.values() (clippy::for_kv_map) in limitador/src/storage/distributed/mod.rs:188
• Simplify match on Result to use ? operator (clippy::question_mark) in limitador/src/lib.rs:396

Both lints were promoted to clippy::all in Rust 1.97 and now fail under the crate's #![deny(clippy::all)]. This unblocks the merge queue for #491 and any other pending PRs.

Test plan

• CI Clippy job passes
• Test suite passes (no behavioral change)

🤖 Generated with Claude Code

Summary by CodeRabbit

• Refactor
  • Simplified internal rate-limit checking while preserving existing behaviour and error handling.
  • Streamlined counter retrieval while keeping remaining-limit and expiry calculations unchanged.
• Chores
  • Adjusted configuration helper annotations to avoid dead-code warnings without changing environment variable behaviour.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: d201bab4-76f7-4398-b09b-8b5e1a33597f

📥 Commits

Reviewing files that changed from the base of the PR and between 2af8776 and 94b9330.

📒 Files selected for processing (1)

• limitador-server/src/config.rs

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📝 Walkthrough

Walkthrough

Three internal Rust implementations were simplified: rate-limit checking uses an early-return guard, distributed counter retrieval iterates directly over stored values, and an environment helper allows dead-code warnings. Runtime behaviour remains unchanged.

Changes

Rate limiter cleanup

Layer / File(s)	Summary
Internal control-flow and counter iteration limitador/src/lib.rs, limitador/src/storage/distributed/mod.rs	find_first_limited_counter uses ? for error propagation, while get_counters iterates over limits_map values without changing filtering or counter calculations.
Environment helper warning handling limitador-server/src/config.rs	value_for is annotated with #[allow(dead_code)]; environment-variable parsing remains unchanged.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Poem

I’m a rabbit with tidy code,
Hopping through limits on the road.
Errors now swiftly leap away,
Counters count in a cleaner array.
Same results bloom—what a day!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states the main change: fixing Clippy errors caused by Rust 1.97 lint promotions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/clippy-rust-1.97

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[eguzki]

There are some clippy errors

error: function `value_for` is never used
  --> limitador-server/src/config.rs:84:8
   |
84 |     fn value_for(env_key: &'static str) -> Option<&'static str> {
   |        ^^^^^^^^^
   |
   = note: `-D dead-code` implied by `-D warnings`
   = help: to override `-D warnings` add `#[expect(dead_code)]` or `#[allow(dead_code)]`

error: function `env_option_is_enabled` is never used
  --> limitador-server/src/config.rs:91:8
   |
91 |     fn env_option_is_enabled(env_name: &str) -> bool {
   |        ^^^^^^^^^^^^^^^^^^^^^

error: could not compile `limitador-server` (bin "limitador-server" test) due to 2 previous errors

[thomasmaas]

Fixed — pushed a second commit that adds #[allow(dead_code)] to value_for and env_option_is_enabled in limitador-server/src/config.rs. These functions are used by lazy_static! initializers but Rust 1.97 flags them as dead code in test-only compilation targets.