Common base class for CEL exceptions, without breaking the existing builtin mappings
Nobody has claimed this yet.
Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 48/100
- Issue type
- Feature
- Clarity
- Clearly specified
- Activity status
- Active
- Domain
- backend-api-design, documentation
Research direction
Start by inspecting python/cel/exceptions.py, map_execution_error_to_python, cel.pyi, and the error-handling how-to. Trace the existing execution and parse error mappings, then verify that the new hierarchy preserves builtin exception handling, supports catching cel.CelError, and is documented in the stub and how-to table.
Written by the indexing model from the issue text.
Description
Follow-up promised when closing #23. Execution errors are mapped to the idiomatic builtin (RuntimeError, TypeError, KeyError, IndexError, ZeroDivisionError, OverflowError) and parse errors to ValueError, which is right for each case but means "did the rule run and fail" needs a five-clause except:
except (RuntimeError, TypeError, KeyError, IndexError, ArithmeticError):
Proposal
Add a cel.CelError hierarchy whose members also inherit from the builtin they replace, so nothing existing breaks:
class CelError(Exception): ...
class CelParseError(CelError, ValueError): ...
class CelRuntimeError(CelError, RuntimeError): ...
class CelTypeError(CelError, TypeError): ...
class CelKeyError(CelError, KeyError): ...
class CelIndexError(CelError, IndexError): ...
class CelZeroDivisionError(CelError, ZeroDivisionError): ...
class CelOverflowError(CelError, OverflowError): ...
except TypeError keeps working; except cel.CelError catches everything CEL raised; except cel.CelParseError separates a bad rule from a failed check.
Implementation notes
PyO3's create_exception! only takes a single base, so define the classes in a small python/cel/exceptions.py and have map_execution_error_to_python look them up from the module once (a GILOnceCell<Py<PyType>> per class) and raise with PyErr::from_type. Add them to cel.pyi and to the error-handling how-to, whose current table becomes the mapping between the two hierarchies.
- Dominant language
- Python
- Stars
- 43
- Forks
- 4
- Avg merge
- 9h 57m
- Merged PRs (30d)
- 14
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
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