mcp-server-semgrep/semgrep-rules/python/lang/correctness/dict-modify-iterating.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
  - id: dict-del-while-iterate
    message:
      "It appears that `$DICT[$KEY]` is a dict with items being deleted while in a for loop. This is usually a bad idea
      and will likely lead to a RuntimeError: dictionary changed size during iteration"
    metadata:
      references:
        - https://docs.python.org/3/library/stdtypes.html#dictionary-view-objects
      category: correctness
      technology:
        - python
    languages: [python]
    severity: WARNING
    pattern-either:
      - pattern: |
          for $KEY, $VALUE in $DICT.items():
              ...
              del $DICT[$KEY]
      - pattern: |
          for $KEY in $DICT.keys():
              ...
              del $DICT[$KEY]