174 lines
6.2 KiB
Python
174 lines
6.2 KiB
Python
"""
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babel.messages.checkers
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~~~~~~~~~~~~~~~~~~~~~~~
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Various routines that help with validation of translations.
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:since: version 0.9
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:copyright: (c) 2013-2023 by the Babel Team.
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:license: BSD, see LICENSE for more details.
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"""
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from __future__ import annotations
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from collections.abc import Callable
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from babel.messages.catalog import PYTHON_FORMAT, Catalog, Message, TranslationError
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#: list of format chars that are compatible to each other
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_string_format_compatibilities = [
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{'i', 'd', 'u'},
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{'x', 'X'},
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{'f', 'F', 'g', 'G'}
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]
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def num_plurals(catalog: Catalog | None, message: Message) -> None:
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"""Verify the number of plurals in the translation."""
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if not message.pluralizable:
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if not isinstance(message.string, str):
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raise TranslationError("Found plural forms for non-pluralizable "
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"message")
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return
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# skip further tests if no catalog is provided.
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elif catalog is None:
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return
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msgstrs = message.string
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if not isinstance(msgstrs, (list, tuple)):
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msgstrs = (msgstrs,)
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if len(msgstrs) != catalog.num_plurals:
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raise TranslationError("Wrong number of plural forms (expected %d)" %
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catalog.num_plurals)
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def python_format(catalog: Catalog | None, message: Message) -> None:
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"""Verify the format string placeholders in the translation."""
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if 'python-format' not in message.flags:
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return
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msgids = message.id
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if not isinstance(msgids, (list, tuple)):
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msgids = (msgids,)
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msgstrs = message.string
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if not isinstance(msgstrs, (list, tuple)):
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msgstrs = (msgstrs,)
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for msgid, msgstr in zip(msgids, msgstrs):
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if msgstr:
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_validate_format(msgid, msgstr)
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def _validate_format(format: str, alternative: str) -> None:
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"""Test format string `alternative` against `format`. `format` can be the
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msgid of a message and `alternative` one of the `msgstr`\\s. The two
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arguments are not interchangeable as `alternative` may contain less
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placeholders if `format` uses named placeholders.
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The behavior of this function is undefined if the string does not use
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string formatting.
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If the string formatting of `alternative` is compatible to `format` the
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function returns `None`, otherwise a `TranslationError` is raised.
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Examples for compatible format strings:
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>>> _validate_format('Hello %s!', 'Hallo %s!')
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>>> _validate_format('Hello %i!', 'Hallo %d!')
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Example for an incompatible format strings:
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>>> _validate_format('Hello %(name)s!', 'Hallo %s!')
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Traceback (most recent call last):
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...
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TranslationError: the format strings are of different kinds
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This function is used by the `python_format` checker.
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:param format: The original format string
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:param alternative: The alternative format string that should be checked
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against format
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:raises TranslationError: on formatting errors
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"""
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def _parse(string: str) -> list[tuple[str, str]]:
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result: list[tuple[str, str]] = []
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for match in PYTHON_FORMAT.finditer(string):
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name, format, typechar = match.groups()
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if typechar == '%' and name is None:
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continue
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result.append((name, str(typechar)))
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return result
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def _compatible(a: str, b: str) -> bool:
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if a == b:
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return True
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for set in _string_format_compatibilities:
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if a in set and b in set:
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return True
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return False
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def _check_positional(results: list[tuple[str, str]]) -> bool:
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positional = None
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for name, _char in results:
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if positional is None:
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positional = name is None
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else:
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if (name is None) != positional:
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raise TranslationError('format string mixes positional '
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'and named placeholders')
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return bool(positional)
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a, b = map(_parse, (format, alternative))
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# now check if both strings are positional or named
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a_positional, b_positional = map(_check_positional, (a, b))
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if a_positional and not b_positional and not b:
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raise TranslationError('placeholders are incompatible')
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elif a_positional != b_positional:
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raise TranslationError('the format strings are of different kinds')
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# if we are operating on positional strings both must have the
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# same number of format chars and those must be compatible
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if a_positional:
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if len(a) != len(b):
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raise TranslationError('positional format placeholders are '
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'unbalanced')
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for idx, ((_, first), (_, second)) in enumerate(zip(a, b)):
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if not _compatible(first, second):
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raise TranslationError('incompatible format for placeholder '
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'%d: %r and %r are not compatible' %
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(idx + 1, first, second))
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# otherwise the second string must not have names the first one
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# doesn't have and the types of those included must be compatible
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else:
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type_map = dict(a)
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for name, typechar in b:
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if name not in type_map:
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raise TranslationError(f'unknown named placeholder {name!r}')
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elif not _compatible(typechar, type_map[name]):
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raise TranslationError(
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f'incompatible format for placeholder {name!r}: '
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f'{typechar!r} and {type_map[name]!r} are not compatible'
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)
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def _find_checkers() -> list[Callable[[Catalog | None, Message], object]]:
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checkers: list[Callable[[Catalog | None, Message], object]] = []
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try:
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from pkg_resources import working_set
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except ImportError:
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pass
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else:
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for entry_point in working_set.iter_entry_points('babel.checkers'):
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checkers.append(entry_point.load())
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if len(checkers) == 0:
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# if pkg_resources is not available or no usable egg-info was found
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# (see #230), just resort to hard-coded checkers
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return [num_plurals, python_format]
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return checkers
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checkers: list[Callable[[Catalog | None, Message], object]] = _find_checkers()
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