pi-lens/rules/tree-sitter-queries/python/notimplemented-boolean-context.yml

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# NotImplemented in Boolean Context
# Detects NotImplemented used in boolean contexts (if, while, and, or)
id: notimplemented-boolean-context
name: NotImplemented in Boolean Context
severity: error
category: reliability
defect_class: correctness
inline_tier: blocking
language: python

message: "NotImplemented should not be used in boolean contexts"

description: |
  NotImplemented is not a boolean value and should not be used in boolean contexts.
  In Python 3.14+, this will raise a DeprecationWarning and eventually an error.
  Use NotImplementedError exception instead, or return NotImplemented from operators.

  ✅ FIX: Raise NotImplementedError instead

  ```python
  def method(self):
      if not self.supported:
          raise NotImplementedError("Not supported")  # Correct
  ```

query: |
  (if_statement
    condition: (identifier) @COND (#eq? @COND "NotImplemented"))
  (while_statement
    condition: (identifier) @COND (#eq? @COND "NotImplemented"))
  (binary_operator
    (identifier) @COND (#eq? @COND "NotImplemented")
    ("and" | "or"))
  (boolean_operator
    (identifier) @COND (#eq? @COND "NotImplemented"))
  (unary_operator
    operator: ("not")
    argument: (identifier) @COND (#eq? @COND "NotImplemented"))

metavars:
  - COND

tags:
  - reliability
  - python-specific
  - deprecation
  - python3.14

examples:
  bad: |
    if NotImplemented:  # BAD - boolean context
        pass

    while NotImplemented:  # BAD
        pass

    result = NotImplemented and True  # BAD

  good: |
    def __eq__(self, other):
        if not isinstance(other, MyClass):
            return NotImplemented  # GOOD - from operator

    raise NotImplementedError("Not supported")  # GOOD - exception

has_fix: true
fix_action: replace_with_notimplemented_error