Stefano Fiorucci
7c6323b960
* adopt X|Y syntax: draft * cast Union * fix pylint + state testing * use X|Y * rm unused imports * trigger e2e tests * fix + simplification * add compatibility tests * rm e2e tests trigger * fix * add relnote * simplify/fix pep604 union parsing * fix comments * test _is_optional_type * introduce _build_pep604_union_type; make _is_union_type private * try removing problematic test
54 lines
1.9 KiB
Python
54 lines
1.9 KiB
Python
# SPDX-FileCopyrightText: 2022-present deepset GmbH <info@deepset.ai>
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#
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# SPDX-License-Identifier: Apache-2.0
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from types import TracebackType
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from lazy_imports.try_import import _DeferredImportExceptionContextManager
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DEFAULT_IMPORT_ERROR_MSG = "Try 'pip install {}'"
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class LazyImport(_DeferredImportExceptionContextManager):
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"""
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A context manager that provides controlled handling of import errors.
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It adds the possibility to customize the error messages.
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NOTE: Despite its name, this class does not delay the actual import operation.
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For installed modules: executes the import immediately.
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For uninstalled modules: captures the error and defers it until check() is called.
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"""
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def __init__(self, message: str = DEFAULT_IMPORT_ERROR_MSG) -> None:
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super().__init__()
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self.import_error_msg = message
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def __exit__(
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self, exc_type: type[Exception] | None, exc_value: Exception | None, traceback: TracebackType | None
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) -> bool | None:
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"""
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Exit the context manager.
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Args:
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exc_type:
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Raised exception type. :obj:`None` if nothing is raised.
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exc_value:
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Raised exception object. :obj:`None` if nothing is raised.
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traceback:
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Associated traceback. :obj:`None` if nothing is raised.
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Returns:
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:obj:`None` if nothing is deferred, otherwise :obj:`True`.
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:obj:`True` will suppress any exceptions avoiding them from propagating.
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"""
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if isinstance(exc_value, ImportError):
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message = (
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f"Haystack failed to import the optional dependency '{exc_value.name}'. "
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f"{self.import_error_msg.format(exc_value.name)}. Original error: {exc_value}"
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)
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self._deferred = (exc_value, message)
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return True
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return None
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