pi-lens/rules/tree-sitter-queries/ruby/ruby-open-struct.yml

Real-time code feedback for pi — LSP, linters, formatters, type-checking, structural analysis & booboo

# Ruby Open Struct
# Detects OpenStruct usage (performance and debugging issues)
id: ruby-open-struct
name: OpenStruct Usage
severity: warning
category: best-practices
defect_class: safety
inline_tier: warning
language: ruby

message: "OpenStruct is slow and makes debugging hard — use a plain class or Struct"

description: |
  OpenStruct is convenient but has poor performance and hides method
  definitions from static analysis. Prefer Struct or plain classes.
  
  ✅ FIX: Use Struct.new or a plain class with attr_accessor.

query: |
  (call_expression
    receiver: (constant) @RECV
    (#eq? @RECV "OpenStruct")
    method: (identifier) @METHOD
    (#eq? @METHOD "new"))

metavars:
  - RECV
  - METHOD

has_fix: false

tags:
  - ruby
  - performance
  - maintainability

examples:
  bad: |
    person = OpenStruct.new(name: "Ada", age: 30)
    person.name  # Slow, hidden method definition
  
  good: |
    Person = Struct.new(:name, :age)
    person = Person.new("Ada", 30)
    person.name  # Fast, explicit method
    
    # Or plain class
    class Person
      attr_accessor :name, :age
    end