Immutability¶

Status: ⏳ PENDING

The inverse of this chapter's rules — practices to recognize and avoid. Each will get a junior-level definition, a real example of the harm it causes, and the clean alternative.

Anti-Patterns to Cover¶

• Mutating method arguments
• Returning mutable references to internal state
• Partial immutability (an immutable wrapper around a mutable map)
• Using setters to 'fix up' a supposedly immutable object
• Deep mutation of an object passed to a constructor (escape via aliasing)

See the chapter README for the positive rules.