Runtime Error Mixin

runtime_error_mixin

Mix-in for making forging-blocks errors catchable as built-in RuntimeError.

Defines RuntimeErrorMixin, which extends Python's built-in RuntimeError.
When listed before Error[...] in a class's bases, the mix-in ensures
isinstance(error, RuntimeError) returns True for that error and its
subclasses. Attach it to errors representing state violations, broken
invariants, and operational failures where except RuntimeError should apply.

RuntimeErrorMixin

Bases: RuntimeError

Mixin — attach before Error[...] in MRO to make errors isinstance(RuntimeError).

Example

from forging_blocks.foundation.errors import Error, ErrorMessage


class BrokenInvariantError(RuntimeErrorMixin, Error[str]):
    pass  # This error represents a broken invariant


err = BrokenInvariantError(ErrorMessage("State corrupted"))
assert isinstance(err, RuntimeError)

Source code in src/forging_blocks/foundation/errors/builtin/runtime_error_mixin.py

class RuntimeErrorMixin(RuntimeError):
    """Mixin — attach before ``Error[...]`` in MRO to make errors ``isinstance(RuntimeError)``.

    Example:
        ```python
        from forging_blocks.foundation.errors import Error, ErrorMessage


        class BrokenInvariantError(RuntimeErrorMixin, Error[str]):
            pass  # This error represents a broken invariant


        err = BrokenInvariantError(ErrorMessage("State corrupted"))
        assert isinstance(err, RuntimeError)
        ```
    """