fix(rust): clear stable Clippy baseline warnings

[lawrencecchen]

Summary

• Clear the stable Rust 1.98 Clippy failures in cmux-proxy, global-proxy, native-core, and sandbox.
• Box HTTP response errors in private proxy helpers to satisfy result_large_err without changing behavior.
• Apply equivalent mechanical fixes for guarded matches, map iteration, byte strings, and cache sorting.
• Keep -D warnings unchanged. This PR does not modify workflows or CI policy.

Verification

• rustup run 1.98.0 cargo fmt --all -- --check passes in all four crates.
• rustup run 1.98.0 cargo clippy --all-targets --all-features -- -D warnings passes in all four crates.
• rustup run 1.98.0 cargo test --all-features --locked passes in all four crates.

The failures were reproduced on fresh main at 9ab841fc0a8aae5f69f0e4328af36ed0f70c5e39; the CI hardening PR remains separate at #1910.

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Summary by cubic

Clears stable Rust 1.98 Clippy warnings in cmux-proxy, global-proxy, native-core, and sandbox without changing behavior.

• Boxes HTTP response errors in private proxy helpers to satisfy result_large_err.
• Applies mechanical fixes for guarded matches, map iteration, byte strings, and cache sorting.
• Keeps -D warnings unchanged; CI policy is untouched.

^{Written for commit 02c838e. Summary will update on new commits.}

Summary by CodeRabbit

• Refactor

  • Improved proxy error handling for more consistent response processing.
  • Simplified rename detection and cache sorting logic without changing results.
  • Streamlined sandbox navigation, pruning, signal forwarding, and terminal protocol handling while preserving existing behavior.
  • Simplified list rendering conditions with no visible output changes.

• Tests

  • Updated test handling for expected connection errors; runtime behavior remains unchanged.

[vercel]

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Project	Deployment	Actions	Updated
cmux-client	Error		Sep 2, 2026 9:06pm UTC
cmux-www	Ready	Preview	Sep 2, 2026 9:06pm UTC

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: 820d6b0e-b9a5-4af4-9e45-f586e9e501e2

📥 Commits

Reviewing files that changed from the base of the PR and between 9ab841f and 02c838e.

📒 Files selected for processing (10)

• apps/global-proxy/src/lib.rs
• apps/global-proxy/tests/proxy_tests.rs
• apps/server/native/core/src/diff/refs.rs
• apps/server/native/core/src/repo/cache.rs
• crates/cmux-proxy/src/lib.rs
• packages/sandbox/src/acp_client/markdown.rs
• packages/sandbox/src/bin/cli.rs
• packages/sandbox/src/bubblewrap.rs
• packages/sandbox/src/mux/runner.rs
• packages/sandbox/src/mux/terminal.rs

Included review availability: Your plan provides up to 4 included reviews per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

The proxy modules now box HTTP response errors through shared result aliases and unwrap them at response boundaries. Other changes simplify equivalent Rust match, sorting, iteration, and byte-comparison expressions. Tests add targeted lint expectations.

Changes

Proxy error boxing

Layer / File(s)	Summary
Box cmux proxy response errors crates/cmux-proxy/src/lib.rs	Proxy handlers use boxed response errors through shared aliases and response_error. HTTP, upgrade, CONNECT, and header validation paths use the new result type.
Box global WebSocket errors apps/global-proxy/src/lib.rs, apps/global-proxy/tests/proxy_tests.rs	Upstream WebSocket errors are boxed, and the handler dereferences them before returning. Test callbacks add targeted lint expectations.

Rust expression cleanup

Layer / File(s)	Summary
Simplify server matching and sorting apps/server/native/core/src/diff/refs.rs, apps/server/native/core/src/repo/cache.rs	Rename detection uses a match guard. Cache sorting uses sort_by_key with Reverse and preserves descending access order.
Simplify sandbox control flow and iteration packages/sandbox/src/acp_client/markdown.rs, packages/sandbox/src/bin/cli.rs, packages/sandbox/src/bubblewrap.rs, packages/sandbox/src/mux/runner.rs	Equivalent match guards, key/value iteration, and key-based sorting replace nested conditionals and comparator closures.
Normalize terminal byte guards packages/sandbox/src/mux/terminal.rs	Terminal intermediate-byte comparisons use dereferenced byte strings with unchanged semantics.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 02c83

This PR applies localized Rust and proxy error-representation cleanup while preserving existing behavior and deployment configuration. Formatting, Clippy, and tests pass, so no actionable merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.69% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 29 functions across 10 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: resolving stable Rust Clippy warnings across the affected crates without changing CI policy.
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.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/rust-clippy-baseline

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[greptile-apps]

Greptile Summary

The PR applies behavior-preserving Rust 1.98 Clippy fixes across proxy, native-core, and sandbox code while retaining strict warning enforcement.

• Boxes private proxy response errors and unboxes them at service response boundaries.
• Rewrites guarded matches, map iteration, stable sorting, and single-byte comparisons into Clippy-preferred forms.
• Adds narrowly scoped lint expectations for dependency-fixed WebSocket callback error types in tests.

Confidence Score: 5/5

The PR appears safe to merge, with no actionable behavioral or security regressions identified.

The changed error paths preserve their response values at service boundaries, and the remaining Clippy-oriented rewrites retain the prior matching, iteration, sorting, and terminal parsing semantics.

Important Files Changed

Filename	Overview
apps/global-proxy/src/lib.rs	Boxes private WebSocket response errors while preserving statuses, bodies, and unboxing at the caller boundary.
crates/cmux-proxy/src/lib.rs	Consolidates proxy helper result aliases around boxed response errors with consistent conversion at the service boundary.
apps/server/native/core/src/diff/refs.rs	Moves rename-record validation into a match guard without changing accepted records or fallback behavior.
apps/server/native/core/src/repo/cache.rs	Replaces descending timestamp comparators with equivalent stable Reverse-key sorting.
packages/sandbox/src/bin/cli.rs	Replaces the prune comparator with equivalent stable ascending key sorting.
packages/sandbox/src/bubblewrap.rs	Uses map key and value iterators where the discarded tuple member was unused.
packages/sandbox/src/mux/terminal.rs	Rewrites single-byte intermediate comparisons to equivalent byte-string expressions.

_{Reviews (1): Last reviewed commit: "fix(rust): clear stable clippy baseline ..." | Re-trigger Greptile}