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• Source mode: Auto
• Repository: RustPython/RustPython
• Branch: main
• File: .coderabbit.yml
• Commit: f862b4b
• Layers: Repository YAML
• Review profile: CHILL
• Plan: Advanced
• Run ID: d1db784b-845f-4a06-9db5-f34811bf7386

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Reviewing files that changed from the base of the PR and between f862b4b and 7ac7328.

Files selected for processing: 1

• crates/stdlib/src/json.rs

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 8 remain after this review.

JSON list and tuple encoding now use bounds-checked element lookups. When a list lookup returns no element, encode_list stops encoding.

Changes: JSON sequence encoding

Layer / File(s)	Summary
Handle optional sequence lookups crates/stdlib/src/json.rs	List and tuple encoding use bounds-checked lookups. encode_list stops when a lookup returns no element. The comment now describes live sequence iteration as matching CPython’s behavior.

Priority: Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: youknowone

Merge Risk: Minimal · up to 7ac73

The change avoids unchecked indexing when lists shrink during JSON encoding while preserving normal output and cleanup paths. No actionable merge-blocking risk was identified; concurrency stress testing remains unverified.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title "Avoid unchecked list indexing in JSON encoder" matches the main change. The PR changes JsonEncoder.encode_list in crates/stdlib/src/json.rs to use bounds-checked lookups that return None in…
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title "Avoid unchecked list indexing in JSON encoder" matches the main change. The PR changes JsonEncoder.encode_list in crates/stdlib/src/json.rs to use bounds-checked lookups that return None instead of direct indexing, so encoding stops when a list shrinks during iteration. The title is concise, specific, and does not use vague terms. It names the subsystem (JSON encoder) and the core change (checked indexing). It does not mention the race-condition motivation or the single-read-guard lookup, but the title does not need to cover every detail.

Full details: Docstring Coverage

Explanation

Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 1 functions across 1 files.

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