Method iter_candidates

pex/interpreter.py:961–1001

Iterate all likely interpreters found in `paths`. NB: The paths can either be directories to search for python binaries or the paths of python binaries themselves. :param paths: The paths to look for python interpreters; by default the `PATH`. :param path_filter: An

(cls, paths=None, path_filter=None)

    @classmethod
    def iter_candidates(cls, paths=None, path_filter=None):
        # type: (Optional[Iterable[str]], Optional[PathFilter]) -> Iterator[InterpreterOrError]
        """Iterate all likely interpreters found in `paths`.

        NB: The paths can either be directories to search for python binaries or the paths of python
        binaries themselves.

        :param paths: The paths to look for python interpreters; by default the `PATH`.
        :param path_filter: An optional predicate to test whether a candidate interpreter's binary
                            path is acceptable.
        :return: A heterogeneous iterator over valid interpreters and (python, error) invalid
                 python binary tuples.
        """
        failed_interpreters = OrderedDict()  # type: MutableMapping[str, Text]

        def iter_interpreters():
            # type: () -> Iterator[PythonInterpreter]
            for candidate in cls._find(
                cls._paths(paths=paths), path_filter=path_filter, error_handler=Retain[str]()
            ):
                if isinstance(candidate, cls):
                    yield candidate
                else:
                    python, exception = cast("InterpreterIdentificationJobError", candidate)
                    if isinstance(exception, Job.Error) and exception.stderr:
                        # We spawned a subprocess to identify the interpreter but the interpreter
                        # could not run our identification code meaning the interpreter is either
                        # broken or old enough that it either can't parse our identification code
                        # or else provide stdlib modules we expect. The stderr should indicate the
                        # broken-ness appropriately.
                        failed_interpreters[python] = exception.stderr.strip()
                    else:
                        # We couldn't even spawn a subprocess to identify the interpreter. The
                        # likely OSError should help identify the underlying issue.
                        failed_interpreters[python] = repr(exception)

        for interpreter in cls._filter(iter_interpreters()):
            yield interpreter

        for python, error in failed_interpreters.items():
            yield python, error

    @classmethod
    def all(cls, paths=None):