avoid-mutating-constant-collections

v1.39.0

warning

effort: 5m

pro+

Warns when a constant collection is being mutated.

Trying to add/remove elements to a constant collection will throw a runtime exception.

Example

❌ Bad:

const global = [1, 2, 3];

class SomeClass {
  static const set = {1, 2, 3};

  final list = const [1, 2, 3];

  void fn() {
    // LINT: Avoid mutating constant collections.
    //  This invocation will throw a runtime exception.
    list.add(1);
    // LINT: Avoid mutating constant collections.
    //  This invocation will throw a runtime exception.
    global.add(2);
    // LINT: Avoid mutating constant collections.
    //  This invocation will throw a runtime exception.
    set.add(3);
  }
}

✅ Good:

class SomeClass {
  static final set = {1, 2, 3}; // now mutable

  final list = [1, 2, 3]; // now mutable

  void fn() {
    list.add(1);
    set.add(3);
  }
}

Additional Resources

• CWE-248: Uncaught Exception

Related Rules

• avoid-collection-methods-with-unrelated-types
• avoid-collection-mutating-methods