Elixir Code Review

Quick Reference

Review Checklist

Code Style

• Module names are CamelCase, function names are snake_case
• Pipe chains start with raw data, not function calls
• Private functions grouped after public functions
• No unnecessary parentheses in function calls without arguments

Pattern Matching

• Functions use pattern matching over conditionals where appropriate
• With clauses have else handling for error cases
• Guards used instead of runtime checks where possible
• Destructuring used in function heads, not body

OTP Basics

• GenServers use handle_continue for expensive init work
• Supervisors use appropriate restart strategies
• No blocking calls in GenServer callbacks
• Proper use of call vs cast (sync vs async)

Documentation

• All public functions have @doc and @spec
• Modules have @moduledoc describing purpose
• Doctests for pure functions where appropriate
• No @doc false on genuinely public functions

Security

• No String.to_atom/1 on user input (use to_existing_atom/1)
• No Code.eval_string/1 on untrusted input
• No :erlang.binary_to_term/1 without :safe option

Valid Patterns (Do NOT Flag)

• Empty function clause for pattern match - def foo(nil), do: nil is valid guard
• Using |> with single transformation - Readability choice, not wrong
• @doc false on callback implementations - Callbacks documented at behaviour level
• Private functions without @spec - @spec optional for internals
• Using Kernel.apply/3 - Valid for dynamic dispatch with known module/function

Context-Sensitive Rules

When to Load References

• Reviewing module/function naming → code-style.md
• Reviewing with/case/cond statements → pattern-matching.md
• Reviewing GenServer/Supervisor code → otp-basics.md
• Reviewing @doc/@moduledoc → documentation.md

Gates — before reporting

Do these in order for the review batch. Do not publish findings until each step passes.

1. Protocol loaded — Read review-verification-protocol and apply its checks for each finding category you use (unused, validation, security, performance, etc.). Pass: For every substantive finding, you can name which protocol subsection you satisfied or state N/A with reason (pure style).
2. Anchored evidence — Pass: Each finding includes a concrete locator: path:line (or line range), or Module.function/arity plus a short quoted snippet from the file.
3. Claims backed by artifacts — For assertions like unused code, missing validation, or security risk, Pass: You attach the supporting artifact (e.g. search results, file read scope) or downgrade the item to an explicit question / uncertain with what you did not verify.

Before Submitting Findings

Complete Gates — before reporting (section above) first; the verification protocol is mandatory input to those gates.