Make importlib.abc.SourceLoader the primary mechanism for importlib.

This required moving the class from importlib/abc.py into
importlib/_bootstrap.py and jiggering some code to work better with the class.
This included changing how the file finder worked to better meet import
semantics. This also led to fixing importlib to handle the empty string from
sys.path as import currently does (and making me wish we didn't support that
instead just required people to insert '.' instead to represent cwd).

It also required making the new set_data abstractmethod create
any needed subdirectories implicitly thanks to __pycache__ (it was either this
or grow the SourceLoader ABC to gain an 'exists' method and either a mkdir
method or have set_data with no data arg mean to create a directory).

Lastly, as an optimization the file loaders cache the file path where the
finder found something to use for loading (this is thanks to having a
sourceless loader separate from the source loader to simplify the code and
cut out stat calls).
Unfortunately test_runpy assumed a loader would always work for a module, even
if you changed from underneath it what it was expected to work with. By simply
dropping the previous loader in test_runpy so the proper loader can be returned
by the finder fixed the failure.

At this point importlib deviates from import on two points:

1. The exception raised when trying to import a file is different (import does
an explicit file check to print a special message, importlib just says the path
cannot be imported as if it was just some module name).

2. the co_filename on a code object is not being set to where bytecode was
actually loaded from instead of where the marshalled code object originally
came from (a solution for this has already been agreed upon on python-dev but has
not been implemented yet; issue8611).

16 files changed, 415 insertions, 542 deletions

diff --git a/Lib/importlib/__init__.py b/Lib/importlib/__init__.py
index 37577ff..2baaf93 100644
--- a/Lib/importlib/__init__.py
+++ b/Lib/importlib/__init__.py
@@ -36,7 +36,7 @@ def _case_ok(directory, check):
     """
     if 'PYTHONCASEOK' in os.environ:
         return True
-    elif check in os.listdir(directory):
+    elif check in os.listdir(directory if directory else os.getcwd()):
         return True
     return False
 
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
index 145be93..2fac499 100644
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -22,7 +22,7 @@ work. One should use importlib as the public-facing version of this module.
 def _path_join(*args):
     """Replacement for os.path.join."""
     return path_sep.join(x[:-len(path_sep)] if x.endswith(path_sep) else x
-                            for x in args)
+                            for x in args if x)
 
 
 def _path_exists(path):
@@ -53,6 +53,8 @@ def _path_isfile(path):
 # XXX Could also expose Modules/getpath.c:isdir()
 def _path_isdir(path):
     """Replacement for os.path.isdir."""
+    if not path:
+        path = _os.getcwd()
     return _path_is_mode_type(path, 0o040000)
 
 
@@ -99,6 +101,8 @@ def _wrap(new, old):
     new.__dict__.update(old.__dict__)
 
 
+code_type = type(_wrap.__code__)
+
 # Finder/loader utility code ##################################################
 
 def set_package(fxn):
@@ -138,7 +142,7 @@ def module_for_loader(fxn):
     the second argument.
 
     """
-    def decorated(self, fullname):
+    def decorated(self, fullname, *args, **kwargs):
         module = sys.modules.get(fullname)
         is_reload = bool(module)
         if not is_reload:
@@ -148,7 +152,7 @@ def module_for_loader(fxn):
             module = imp.new_module(fullname)
             sys.modules[fullname] = module
         try:
-            return fxn(self, module)
+            return fxn(self, module, *args, **kwargs)
         except:
             if not is_reload:
                 del sys.modules[fullname]
@@ -301,7 +305,59 @@ class FrozenImporter:
         return imp.is_frozen_package(fullname)
 
 
-class SourceLoader:
+class _LoaderBasics:
+
+    """Base class of common code needed by both SourceLoader and
+    _SourcelessFileLoader."""
+
+    def is_package(self, fullname):
+        """Concrete implementation of InspectLoader.is_package by checking if
+        the path returned by get_filename has a filename of '__init__.py'."""
+        filename = self.get_filename(fullname).rpartition(path_sep)[2]
+        return filename.rsplit('.', 1)[0] == '__init__'
+
+    def _bytes_from_bytecode(self, fullname, data, source_mtime):
+        """Return the marshalled bytes from bytecode, verifying the magic
+        number and timestamp alon the way.
+
+        If source_mtime is None then skip the timestamp check.
+
+        """
+        magic = data[:4]
+        raw_timestamp = data[4:8]
+        if len(magic) != 4 or magic != imp.get_magic():
+            raise ImportError("bad magic number in {}".format(fullname))
+        elif len(raw_timestamp) != 4:
+            raise EOFError("bad timestamp in {}".format(fullname))
+        elif source_mtime is not None:
+            if marshal._r_long(raw_timestamp) != source_mtime:
+                raise ImportError("bytecode is stale for {}".format(fullname))
+        # Can't return the code object as errors from marshal loading need to
+        # propagate even when source is available.
+        return data[8:]
+
+    @module_for_loader
+    def _load_module(self, module, *, sourceless=False):
+        """Helper for load_module able to handle either source or sourceless
+        loading."""
+        name = module.__name__
+        code_object = self.get_code(name)
+        module.__file__ = self.get_filename(name)
+        if not sourceless:
+            module.__cached__ = imp.cache_from_source(module.__file__)
+        else:
+            module.__cached__ = module.__file__
+        module.__package__ = name
+        if self.is_package(name):
+            module.__path__ = [module.__file__.rsplit(path_sep, 1)[0]]
+        else:
+            module.__package__ = module.__package__.rpartition('.')[0]
+        module.__loader__ = self
+        exec(code_object, module.__dict__)
+        return module
+
+
+class SourceLoader(_LoaderBasics):
 
     def path_mtime(self, path:str) -> int:
         """Optional method that returns the modification time for the specified
@@ -320,11 +376,6 @@ class SourceLoader:
         """
         raise NotImplementedError
 
-    def is_package(self, fullname):
-        """Concrete implementation of InspectLoader.is_package by checking if
-        the path returned by get_filename has a filename of '__init__.py'."""
-        filename = self.get_filename(fullname).rsplit(path_sep, 1)[1]
-        return filename.rsplit('.', 1)[0] == '__init__'
 
     def get_source(self, fullname):
         """Concrete implementation of InspectLoader.get_source."""
@@ -359,12 +410,18 @@ class SourceLoader:
                 except IOError:
                     pass
                 else:
-                    magic = data[:4]
-                    raw_timestamp = data[4:8]
-                    if (len(magic) == 4 and len(raw_timestamp) == 4 and
-                            magic == imp.get_magic() and
-                            marshal._r_long(raw_timestamp) == source_mtime):
-                        return marshal.loads(data[8:])
+                    try:
+                        bytes_data = self._bytes_from_bytecode(fullname, data,
+                                                               source_mtime)
+                    except (ImportError, EOFError):
+                        pass
+                    else:
+                        found = marshal.loads(bytes_data)
+                        if isinstance(found, code_type):
+                            return found
+                        else:
+                            msg = "Non-code object in {}"
+                            raise ImportError(msg.format(bytecode_path))
         source_bytes = self.get_data(source_path)
         code_object = compile(source_bytes, source_path, 'exec',
                                 dont_inherit=True)
@@ -382,8 +439,7 @@ class SourceLoader:
                 pass
         return code_object
 
-    @module_for_loader
-    def load_module(self, module):
+    def load_module(self, fullname):
         """Concrete implementation of Loader.load_module.
 
         Requires ExecutionLoader.get_filename and ResourceLoader.get_data to be
@@ -391,31 +447,17 @@ class SourceLoader:
         get_code uses/writes bytecode.
 
         """
-        name = module.__name__
-        code_object = self.get_code(name)
-        module.__file__ = self.get_filename(name)
-        module.__cached__ = imp.cache_from_source(module.__file__)
-        module.__package__ = name
-        is_package = self.is_package(name)
-        if is_package:
-            module.__path__ = [module.__file__.rsplit(path_sep, 1)[0]]
-        else:
-            module.__package__ = module.__package__.rpartition('.')[0]
-        module.__loader__ = self
-        exec(code_object, module.__dict__)
-        return module
-
+        return self._load_module(fullname)
 
-class _SourceFileLoader(SourceLoader):
 
-    """Concrete implementation of SourceLoader.
+class _FileLoader:
 
-    NOT A PUBLIC CLASS! Do not expect any API stability from this class, so DO
-    NOT SUBCLASS IN YOUR OWN CODE!
-
-    """
+    """Base file loader class which implements the loader protocol methods that
+    require file system usage."""
 
     def __init__(self, fullname, path):
+        """Cache the module name and the path to the file found by the
+        finder."""
         self._name = fullname
         self._path = path
 
@@ -424,272 +466,66 @@ class _SourceFileLoader(SourceLoader):
         """Return the path to the source file as found by the finder."""
         return self._path
 
+    def get_data(self, path):
+        """Return the data from path as raw bytes."""
+        with _closing(_io.FileIO(path, 'r')) as file:
+            return file.read()
+
+
+class _SourceFileLoader(_FileLoader, SourceLoader):
+
+    """Concrete implementation of SourceLoader using the file system."""
+
     def path_mtime(self, path):
         """Return the modification time for the path."""
         return int(_os.stat(path).st_mtime)
 
-    def set_data(self, data, path):
+    def set_data(self, path, data):
         """Write bytes data to a file."""
         try:
-            with _closing(_io.FileIO(bytecode_path, 'w')) as file:
+            with _closing(_io.FileIO(path, 'wb')) as file:
                 file.write(data)
         except IOError as exc:
-            if exc.errno != errno.EACCES:
+            if exc.errno == errno.ENOENT:
+                directory, _, filename = path.rpartition(path_sep)
+                sub_directories = []
+                while not _path_isdir(directory):
+                    directory, _, sub_dir = directory.rpartition(path_sep)
+                    sub_directories.append(sub_dir)
+                    for part in reversed(sub_directories):
+                        directory = _path_join(directory, part)
+                        try:
+                            _os.mkdir(directory)
+                        except IOError as exc:
+                            if exc.errno != errno.EACCES:
+                                raise
+                            else:
+                                return
+                return self.set_data(path, data)
+            elif exc.errno != errno.EACCES:
                 raise
 
 
-class PyLoader:
-
-    """Loader base class for Python source code.
-
-    Subclasses need to implement the methods:
-
-    - source_path
-    - get_data
-    - is_package
-
-    """
-
-    @module_for_loader
-    def load_module(self, module):
-        """Initialize the module."""
-        name = module.__name__
-        code_object = self.get_code(module.__name__)
-        module.__file__ = self.get_filename(name)
-        if self.is_package(name):
-            module.__path__  = [module.__file__.rsplit(path_sep, 1)[0]]
-        module.__package__ = module.__name__
-        if not hasattr(module, '__path__'):
-            module.__package__ = module.__package__.rpartition('.')[0]
-        module.__loader__ = self
-        exec(code_object, module.__dict__)
-        return module
-
-    def get_filename(self, fullname):
-        """Return the path to the source file, else raise ImportError."""
-        path = self.source_path(fullname)
-        if path is not None:
-            return path
-        else:
-            raise ImportError("no source path available for "
-                                "{0!r}".format(fullname))
-
-    def get_code(self, fullname):
-        """Get a code object from source."""
-        source_path = self.source_path(fullname)
-        if source_path is None:
-            message = "a source path must exist to load {0}".format(fullname)
-            raise ImportError(message)
-        source = self.get_data(source_path)
-        return compile(source, source_path, 'exec', dont_inherit=True)
-
-    # Never use in implementing import! Imports code within the method.
-    def get_source(self, fullname):
-        """Return the source code for a module.
-
-        self.source_path() and self.get_data() are used to implement this
-        method.
-
-        """
-        path = self.source_path(fullname)
-        if path is None:
-            return None
-        try:
-            source_bytes = self.get_data(path)
-        except IOError:
-            return ImportError("source not available through get_data()")
-        import io
-        import tokenize
-        encoding = tokenize.detect_encoding(io.BytesIO(source_bytes).readline)
-        return source_bytes.decode(encoding[0])
-
-
-class PyPycLoader(PyLoader):
-
-    """Loader base class for Python source and bytecode.
+class _SourcelessFileLoader(_FileLoader, _LoaderBasics):
 
-    Requires implementing the methods needed for PyLoader as well as
-    source_mtime, bytecode_path, and write_bytecode.
+    """Loader which handles sourceless file imports."""
 
-    """
-
-    def get_filename(self, fullname):
-        """Return the source or bytecode file path."""
-        path = self.source_path(fullname)
-        if path is not None:
-            return path
-        path = self.bytecode_path(fullname)
-        if path is not None:
-            return path
-        raise ImportError("no source or bytecode path available for "
-                            "{0!r}".format(fullname))
+    def load_module(self, fullname):
+        return self._load_module(fullname, sourceless=True)
 
     def get_code(self, fullname):
-        """Get a code object from source or bytecode."""
-        # XXX Care enough to make sure this call does not happen if the magic
-        #     number is bad?
-        source_timestamp = self.source_mtime(fullname)
-        # Try to use bytecode if it is available.
-        bytecode_path = self.bytecode_path(fullname)
-        if bytecode_path:
-            data = self.get_data(bytecode_path)
-            try:
-                magic = data[:4]
-                if len(magic) < 4:
-                    raise ImportError("bad magic number in {}".format(fullname))
-                raw_timestamp = data[4:8]
-                if len(raw_timestamp) < 4:
-                    raise EOFError("bad timestamp in {}".format(fullname))
-                pyc_timestamp = marshal._r_long(raw_timestamp)
-                bytecode = data[8:]
-                # Verify that the magic number is valid.
-                if imp.get_magic() != magic:
-                    raise ImportError("bad magic number in {}".format(fullname))
-                # Verify that the bytecode is not stale (only matters when
-                # there is source to fall back on.
-                if source_timestamp:
-                    if pyc_timestamp < source_timestamp:
-                        raise ImportError("bytecode is stale")
-            except (ImportError, EOFError):
-                # If source is available give it a shot.
-                if source_timestamp is not None:
-                    pass
-                else:
-                    raise
-            else:
-                # Bytecode seems fine, so try to use it.
-                # XXX If the bytecode is ill-formed, would it be beneficial to
-                #     try for using source if available and issue a warning?
-                return marshal.loads(bytecode)
-        elif source_timestamp is None:
-            raise ImportError("no source or bytecode available to create code "
-                                "object for {0!r}".format(fullname))
-        # Use the source.
-        code_object = super().get_code(fullname)
-        # Generate bytecode and write it out.
-        if not sys.dont_write_bytecode:
-            data = bytearray(imp.get_magic())
-            data.extend(marshal._w_long(source_timestamp))
-            data.extend(marshal.dumps(code_object))
-            self.write_bytecode(fullname, data)
-        return code_object
-
-
-class _PyFileLoader(PyLoader):
-
-    """Load a Python source file."""
-
-    def __init__(self, name, path, is_pkg):
-        self._name = name
-        self._is_pkg = is_pkg
-        # Figure out the base path based on whether it was source or bytecode
-        # that was found.
-        try:
-            self._base_path = _path_without_ext(path, imp.PY_SOURCE)
-        except ValueError:
-            self._base_path = _path_without_ext(path, imp.PY_COMPILED)
-
-    def _find_path(self, ext_type):
-        """Find a path from the base path and the specified extension type that
-        exists, returning None if one is not found."""
-        for suffix in _suffix_list(ext_type):
-            path = self._base_path + suffix
-            if _path_exists(path):
-                return path
+        path = self.get_filename(fullname)
+        data = self.get_data(path)
+        bytes_data = self._bytes_from_bytecode(fullname, data, None)
+        found = marshal.loads(bytes_data)
+        if isinstance(found, code_type):
+            return found
         else:
-            return None
-
-    @_check_name
-    def source_path(self, fullname):
-        """Return the path to an existing source file for the module, or None
-        if one cannot be found."""
-        # Not a property so that it is easy to override.
-        return self._find_path(imp.PY_SOURCE)
+            raise ImportError("Non-code object in {}".format(path))
 
-    def get_data(self, path):
-        """Return the data from path as raw bytes."""
-        return _io.FileIO(path, 'r').read()  # Assuming bytes.
-
-    @_check_name
-    def is_package(self, fullname):
-        """Return a boolean based on whether the module is a package.
-
-        Raises ImportError (like get_source) if the loader cannot handle the
-        package.
-
-        """
-        return self._is_pkg
-
-
-class _PyPycFileLoader(PyPycLoader, _PyFileLoader):
-
-    """Load a module from a source or bytecode file."""
-
-    def _find_path(self, ext_type):
-        """Return PEP 3147 path if ext_type is PY_COMPILED, otherwise
-        super()._find_path() is called."""
-        if ext_type == imp.PY_COMPILED:
-            # We don't really care what the extension on self._base_path is,
-            # as long as it has exactly one dot.
-            source_path = self._base_path + '.py'
-            pycache_path = imp.cache_from_source(source_path)
-            legacy_path = self._base_path + '.pyc'
-            # The rule is: if the source file exists, then Python always uses
-            # the __pycache__/foo.<tag>.pyc file.  If the source file does not
-            # exist, then Python uses the legacy path.
-            pyc_path = (pycache_path
-                        if _path_exists(source_path)
-                        else legacy_path)
-            return (pyc_path if _path_exists(pyc_path) else None)
-        return super()._find_path(ext_type)
-
-    @_check_name
-    def source_mtime(self, name):
-        """Return the modification time of the source for the specified
-        module."""
-        source_path = self.source_path(name)
-        if not source_path:
-            return None
-        return int(_os.stat(source_path).st_mtime)
-
-    @_check_name
-    def bytecode_path(self, fullname):
-        """Return the path to a bytecode file, or None if one does not
-        exist."""
-        # Not a property for easy overriding.
-        return self._find_path(imp.PY_COMPILED)
-
-    @_check_name
-    def write_bytecode(self, name, data):
-        """Write out 'data' for the specified module, returning a boolean
-        signifying if the write-out actually occurred.
-
-        Raises ImportError (just like get_source) if the specified module
-        cannot be handled by the loader.
-
-        """
-        bytecode_path = self.bytecode_path(name)
-        if not bytecode_path:
-            source_path = self.source_path(name)
-            bytecode_path = imp.cache_from_source(source_path)
-            # Ensure that the __pycache__ directory exists.  We can't use
-            # os.path.dirname() here.
-            dirname, sep, basename = bytecode_path.rpartition(path_sep)
-            try:
-                _os.mkdir(dirname)
-            except OSError as error:
-                if error.errno != errno.EEXIST:
-                    raise
-        try:
-            # Assuming bytes.
-            with _closing(_io.FileIO(bytecode_path, 'w')) as bytecode_file:
-                bytecode_file.write(data)
-                return True
-        except IOError as exc:
-            if exc.errno == errno.EACCES:
-                return False
-            else:
-                raise
+    def get_source(self, fullname):
+        """Return None as there is no source code."""
+        return None
 
 
 class _ExtensionFileLoader:
@@ -700,7 +536,7 @@ class _ExtensionFileLoader:
 
     """
 
-    def __init__(self, name, path, is_pkg):
+    def __init__(self, name, path):
         """Initialize the loader.
 
         If is_pkg is True then an exception is raised as extension modules
@@ -709,8 +545,6 @@ class _ExtensionFileLoader:
         """
         self._name = name
         self._path = path
-        if is_pkg:
-            raise ValueError("extension modules cannot be packages")
 
     @_check_name
     @set_package
@@ -808,147 +642,88 @@ class PathFinder:
             return None
 
 
-class _ChainedFinder:
-
-    """Finder that sequentially calls other finders."""
-
-    def __init__(self, *finders):
-        self._finders = finders
-
-    def find_module(self, fullname, path=None):
-        for finder in self._finders:
-            result = finder.find_module(fullname, path)
-            if result:
-                return result
-        else:
-            return None
-
-
 class _FileFinder:
 
-    """Base class for file finders.
-
-    Subclasses are expected to define the following attributes:
-
-        * _suffixes
-            Sequence of file suffixes whose order will be followed.
+    """File-based finder.
 
-        * _possible_package
-            True if importer should check for packages.
-
-        * _loader
-            A callable that takes the module name, a file path, and whether
-            the path points to a package and returns a loader for the module
-            found at that path.
+    Constructor takes a list of objects detailing what file extensions their
+    loader supports along with whether it can be used for a package.
 
     """
 
-    def __init__(self, path_entry):
-        """Initialize an importer for the passed-in sys.path entry (which is
-        assumed to have already been verified as an existing directory).
-
-        Can be used as an entry on sys.path_hook.
-
-        """
-        absolute_path = _path_absolute(path_entry)
-        if not _path_isdir(absolute_path):
-            raise ImportError("only directories are supported")
-        self._path_entry = absolute_path
-
-    def find_module(self, fullname, path=None):
+    def __init__(self, path, *details):
+        """Initialize with finder details."""
+        packages = []
+        modules = []
+        for detail in details:
+            modules.extend((suffix, detail.loader) for suffix in detail.suffixes)
+            if detail.supports_packages:
+                packages.extend((suffix, detail.loader)
+                                for suffix in detail.suffixes)
+        self.packages = packages
+        self.modules = modules
+        self.path = path
+
+    def find_module(self, fullname):
+        """Try to find a loader for the specified module."""
         tail_module = fullname.rpartition('.')[2]
-        package_directory = None
-        if self._possible_package:
-            for ext in self._suffixes:
-                package_directory = _path_join(self._path_entry, tail_module)
-                init_filename = '__init__' + ext
-                package_init = _path_join(package_directory, init_filename)
-                if (_path_isfile(package_init) and
-                        _case_ok(self._path_entry, tail_module) and
-                        _case_ok(package_directory, init_filename)):
-                    return self._loader(fullname, package_init, True)
-        for ext in self._suffixes:
-            file_name = tail_module + ext
-            file_path = _path_join(self._path_entry, file_name)
-            if (_path_isfile(file_path) and
-                    _case_ok(self._path_entry, file_name)):
-                return self._loader(fullname, file_path, False)
-        else:
-            # Raise a warning if it matches a directory w/o an __init__ file.
-            if (package_directory is not None and
-                    _path_isdir(package_directory) and
-                    _case_ok(self._path_entry, tail_module)):
-                _warnings.warn("Not importing directory %s: missing __init__"
-                                % package_directory, ImportWarning)
-            return None
-
-
-class _PyFileFinder(_FileFinder):
-
-    """Importer for source/bytecode files."""
-
-    _possible_package = True
-    _loader = _PyFileLoader
-
-    def __init__(self, path_entry):
-        # Lack of imp during class creation means _suffixes is set here.
-        # Make sure that Python source files are listed first!  Needed for an
-        # optimization by the loader.
-        self._suffixes = _suffix_list(imp.PY_SOURCE)
-        super().__init__(path_entry)
-
-
-class _PyPycFileFinder(_PyFileFinder):
+        base_path = _path_join(self.path, tail_module)
+        if _path_isdir(base_path) and _case_ok(self.path, tail_module):
+            for suffix, loader in self.packages:
+                init_filename = '__init__' + suffix
+                full_path = _path_join(base_path, init_filename)
+                if (_path_isfile(full_path) and
+                        _case_ok(base_path, init_filename)):
+                    return loader(fullname, full_path)
+            else:
+                msg = "Not importing directory {}: missing __init__"
+                _warnings.warn(msg.format(base_path), ImportWarning)
+        for suffix, loader in self.modules:
+            mod_filename = tail_module + suffix
+            full_path = _path_join(self.path, mod_filename)
+            if _path_isfile(full_path) and _case_ok(self.path, mod_filename):
+                return loader(fullname, full_path)
+        return None
 
-    """Finder for source and bytecode files."""
+class _SourceFinderDetails:
 
-    _loader = _PyPycFileLoader
+    loader = _SourceFileLoader
+    supports_packages = True
 
-    def __init__(self, path_entry):
-        super().__init__(path_entry)
-        self._suffixes += _suffix_list(imp.PY_COMPILED)
+    def __init__(self):
+        self.suffixes = _suffix_list(imp.PY_SOURCE)
 
+class _SourcelessFinderDetails:
 
+    loader = _SourcelessFileLoader
+    supports_packages = True
 
+    def __init__(self):
+        self.suffixes = _suffix_list(imp.PY_COMPILED)
 
-class _ExtensionFileFinder(_FileFinder):
 
-    """Importer for extension files."""
+class _ExtensionFinderDetails:
 
-    _possible_package = False
-    _loader = _ExtensionFileLoader
+    loader = _ExtensionFileLoader
+    supports_packages = False
 
-    def __init__(self, path_entry):
-        # Assigning to _suffixes here instead of at the class level because
-        # imp is not imported at the time of class creation.
-        self._suffixes = _suffix_list(imp.C_EXTENSION)
-        super().__init__(path_entry)
+    def __init__(self):
+        self.suffixes = _suffix_list(imp.C_EXTENSION)
 
 
 # Import itself ###############################################################
 
-def _chained_path_hook(*path_hooks):
-    """Create a closure which sequentially checks path hooks to see which ones
-    (if any) can work with a path."""
-    def path_hook(entry):
-        """Check to see if 'entry' matches any of the enclosed path hooks."""
-        finders = []
-        for hook in path_hooks:
-            try:
-                finder = hook(entry)
-            except ImportError:
-                continue
-            else:
-                finders.append(finder)
-        if not finders:
-            raise ImportError("no finder found")
-        else:
-            return _ChainedFinder(*finders)
-
-    return path_hook
+def _file_path_hook(path):
+    """If the path is a directory, return a file-based finder."""
+    if _path_isdir(path):
+        return _FileFinder(path, _ExtensionFinderDetails(),
+                           _SourceFinderDetails(),
+                           _SourcelessFinderDetails())
+    else:
+        raise ImportError("only directories are supported")
 
 
-_DEFAULT_PATH_HOOK = _chained_path_hook(_ExtensionFileFinder, _PyPycFileFinder)
+_DEFAULT_PATH_HOOK = _file_path_hook
 
 class _DefaultPathFinder(PathFinder):
 
diff --git a/Lib/importlib/abc.py b/Lib/importlib/abc.py
index a9cd3c8..6a7e364 100644
--- a/Lib/importlib/abc.py
+++ b/Lib/importlib/abc.py
@@ -182,8 +182,6 @@ class PyLoader(SourceLoader):
         else:
             return path
 
-PyLoader.register(_bootstrap.PyLoader)
-
 
 class PyPycLoader(PyLoader):
 
@@ -266,7 +264,6 @@ class PyPycLoader(PyLoader):
             self.write_bytecode(fullname, data)
         return code_object
 
-
     @abc.abstractmethod
     def source_mtime(self, fullname:str) -> int:
         """Abstract method which when implemented should return the
@@ -285,5 +282,3 @@ class PyPycLoader(PyLoader):
         bytecode for the module, returning a boolean representing whether the
         bytecode was written or not."""
         raise NotImplementedError
-
-PyPycLoader.register(_bootstrap.PyPycLoader)
diff --git a/Lib/importlib/test/extension/test_case_sensitivity.py b/Lib/importlib/test/extension/test_case_sensitivity.py
index 3865539..e062fb6 100644
--- a/Lib/importlib/test/extension/test_case_sensitivity.py
+++ b/Lib/importlib/test/extension/test_case_sensitivity.py
@@ -13,7 +13,8 @@ class ExtensionModuleCaseSensitivityTest(unittest.TestCase):
         good_name = ext_util.NAME
         bad_name = good_name.upper()
         assert good_name != bad_name
-        finder = _bootstrap._ExtensionFileFinder(ext_util.PATH)
+        finder = _bootstrap._FileFinder(ext_util.PATH,
+                                        _bootstrap._ExtensionFinderDetails())
         return finder.find_module(bad_name)
 
     def test_case_sensitive(self):
diff --git a/Lib/importlib/test/extension/test_finder.py b/Lib/importlib/test/extension/test_finder.py
index 546a176..ea97483 100644
--- a/Lib/importlib/test/extension/test_finder.py
+++ b/Lib/importlib/test/extension/test_finder.py
@@ -9,7 +9,8 @@ class FinderTests(abc.FinderTests):
     """Test the finder for extension modules."""
 
     def find_module(self, fullname):
-        importer = _bootstrap._ExtensionFileFinder(util.PATH)
+        importer = _bootstrap._FileFinder(util.PATH,
+                                          _bootstrap._ExtensionFinderDetails())
         return importer.find_module(fullname)
 
     def test_module(self):
diff --git a/Lib/importlib/test/extension/test_loader.py b/Lib/importlib/test/extension/test_loader.py
index 7f6eda3..4a783db 100644
--- a/Lib/importlib/test/extension/test_loader.py
+++ b/Lib/importlib/test/extension/test_loader.py
@@ -13,7 +13,7 @@ class LoaderTests(abc.LoaderTests):
 
     def load_module(self, fullname):
         loader = _bootstrap._ExtensionFileLoader(ext_util.NAME,
-                                                ext_util.FILEPATH, False)
+                                                ext_util.FILEPATH)
         return loader.load_module(fullname)
 
     def test_module(self):
diff --git a/Lib/importlib/test/extension/test_path_hook.py b/Lib/importlib/test/extension/test_path_hook.py
index bf2f411..4610420 100644
--- a/Lib/importlib/test/extension/test_path_hook.py
+++ b/Lib/importlib/test/extension/test_path_hook.py
@@ -14,7 +14,7 @@ class PathHookTests(unittest.TestCase):
     # XXX Should it only work for directories containing an extension module?
 
     def hook(self, entry):
-        return _bootstrap._ExtensionFileFinder(entry)
+        return _bootstrap._file_path_hook(entry)
 
     def test_success(self):
         # Path hook should handle a directory where a known extension module
diff --git a/Lib/importlib/test/import_/test_path.py b/Lib/importlib/test/import_/test_path.py
index 146eb78..2faa231 100644
--- a/Lib/importlib/test/import_/test_path.py
+++ b/Lib/importlib/test/import_/test_path.py
@@ -5,6 +5,7 @@ from . import util as import_util
 import imp
 import os
 import sys
+import tempfile
 from test import support
 from types import MethodType
 import unittest
@@ -80,23 +81,28 @@ class DefaultPathFinderTests(unittest.TestCase):
 
     def test_implicit_hooks(self):
         # Test that the implicit path hooks are used.
-        existing_path = os.path.dirname(support.TESTFN)
         bad_path = '<path>'
         module = '<module>'
         assert not os.path.exists(bad_path)
-        with util.import_state():
-            nothing = _bootstrap._DefaultPathFinder.find_module(module,
-                                                           path=[existing_path])
-            self.assertTrue(nothing is None)
-            self.assertTrue(existing_path in sys.path_importer_cache)
-            self.assertTrue(not isinstance(sys.path_importer_cache[existing_path],
-                                        imp.NullImporter))
-            nothing = _bootstrap._DefaultPathFinder.find_module(module,
-                                                                path=[bad_path])
-            self.assertTrue(nothing is None)
-            self.assertTrue(bad_path in sys.path_importer_cache)
-            self.assertTrue(isinstance(sys.path_importer_cache[bad_path],
-                                    imp.NullImporter))
+        existing_path = tempfile.mkdtemp()
+        try:
+            with util.import_state():
+                nothing = _bootstrap._DefaultPathFinder.find_module(module,
+                                                        path=[existing_path])
+                self.assertTrue(nothing is None)
+                self.assertTrue(existing_path in sys.path_importer_cache)
+                result = isinstance(sys.path_importer_cache[existing_path],
+                                    imp.NullImporter)
+                self.assertFalse(result)
+                nothing = _bootstrap._DefaultPathFinder.find_module(module,
+                                                            path=[bad_path])
+                self.assertTrue(nothing is None)
+                self.assertTrue(bad_path in sys.path_importer_cache)
+                self.assertTrue(isinstance(sys.path_importer_cache[bad_path],
+                                           imp.NullImporter))
+        finally:
+            os.rmdir(existing_path)
+
 
     def test_path_importer_cache_has_None(self):
         # Test that the default hook is used when sys.path_importer_cache
diff --git a/Lib/importlib/test/regrtest.py b/Lib/importlib/test/regrtest.py
index 17985fb..b103ae7d 100644
--- a/Lib/importlib/test/regrtest.py
+++ b/Lib/importlib/test/regrtest.py
@@ -6,9 +6,11 @@ Otherwise all command-line options valid for test.regrtest are also valid for
 this script.
 
 XXX FAILING
-    test_import
-        execution bit
+  * test_import
+    - test_incorrect_code_name
         file name differing between __file__ and co_filename (r68360 on trunk)
+    - test_import_by_filename
+        exception for trying to import by file name does not match
 
 """
 import importlib
diff --git a/Lib/importlib/test/source/test_abc_loader.py b/Lib/importlib/test/source/test_abc_loader.py
index 6bdaadb..ce0021f 100644
--- a/Lib/importlib/test/source/test_abc_loader.py
+++ b/Lib/importlib/test/source/test_abc_loader.py
@@ -815,6 +815,7 @@ class AbstractMethodImplTests(unittest.TestCase):
     def test_Loader(self):
         self.raises_NotImplementedError(self.Loader(), 'load_module')
 
+    # XXX misplaced; should be somewhere else
     def test_Finder(self):
         self.raises_NotImplementedError(self.Finder(), 'find_module')
 
diff --git a/Lib/importlib/test/source/test_case_sensitivity.py b/Lib/importlib/test/source/test_case_sensitivity.py
index 6fad881..73777de 100644
--- a/Lib/importlib/test/source/test_case_sensitivity.py
+++ b/Lib/importlib/test/source/test_case_sensitivity.py
@@ -19,7 +19,9 @@ class CaseSensitivityTest(unittest.TestCase):
     assert name != name.lower()
 
     def find(self, path):
-        finder = _bootstrap._PyPycFileFinder(path)
+        finder = _bootstrap._FileFinder(path,
+                                        _bootstrap._SourceFinderDetails(),
+                                        _bootstrap._SourcelessFinderDetails())
         return finder.find_module(self.name)
 
     def sensitivity_test(self):
@@ -27,7 +29,7 @@ class CaseSensitivityTest(unittest.TestCase):
         sensitive_pkg = 'sensitive.{0}'.format(self.name)
         insensitive_pkg = 'insensitive.{0}'.format(self.name.lower())
         context = source_util.create_modules(insensitive_pkg, sensitive_pkg)
-        with  context as mapping:
+        with context as mapping:
             sensitive_path = os.path.join(mapping['.root'], 'sensitive')
             insensitive_path = os.path.join(mapping['.root'], 'insensitive')
             return self.find(sensitive_path), self.find(insensitive_path)
@@ -37,7 +39,7 @@ class CaseSensitivityTest(unittest.TestCase):
             env.unset('PYTHONCASEOK')
             sensitive, insensitive = self.sensitivity_test()
             self.assertTrue(hasattr(sensitive, 'load_module'))
-            self.assertIn(self.name, sensitive._base_path)
+            self.assertIn(self.name, sensitive.get_filename(self.name))
             self.assertIsNone(insensitive)
 
     def test_insensitive(self):
@@ -45,9 +47,9 @@ class CaseSensitivityTest(unittest.TestCase):
             env.set('PYTHONCASEOK', '1')
             sensitive, insensitive = self.sensitivity_test()
             self.assertTrue(hasattr(sensitive, 'load_module'))
-            self.assertIn(self.name, sensitive._base_path)
+            self.assertIn(self.name, sensitive.get_filename(self.name))
             self.assertTrue(hasattr(insensitive, 'load_module'))
-            self.assertIn(self.name, insensitive._base_path)
+            self.assertIn(self.name, insensitive.get_filename(self.name))
 
 
 def test_main():
diff --git a/Lib/importlib/test/source/test_file_loader.py b/Lib/importlib/test/source/test_file_loader.py
index 343e120..0a85bc4 100644
--- a/Lib/importlib/test/source/test_file_loader.py
+++ b/Lib/importlib/test/source/test_file_loader.py
@@ -4,6 +4,7 @@ from .. import abc
 from . import util as source_util
 
 import imp
+import marshal
 import os
 import py_compile
 import stat
@@ -23,8 +24,7 @@ class SimpleTest(unittest.TestCase):
     # [basic]
     def test_module(self):
         with source_util.create_modules('_temp') as mapping:
-            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
-                                                    False)
+            loader = _bootstrap._SourceFileLoader('_temp', mapping['_temp'])
             module = loader.load_module('_temp')
             self.assertTrue('_temp' in sys.modules)
             check = {'__name__': '_temp', '__file__': mapping['_temp'],
@@ -34,9 +34,8 @@ class SimpleTest(unittest.TestCase):
 
     def test_package(self):
         with source_util.create_modules('_pkg.__init__') as mapping:
-            loader = _bootstrap._PyPycFileLoader('_pkg',
-                                                 mapping['_pkg.__init__'],
-                                                 True)
+            loader = _bootstrap._SourceFileLoader('_pkg',
+                                                 mapping['_pkg.__init__'])
             module = loader.load_module('_pkg')
             self.assertTrue('_pkg' in sys.modules)
             check = {'__name__': '_pkg', '__file__': mapping['_pkg.__init__'],
@@ -48,8 +47,8 @@ class SimpleTest(unittest.TestCase):
 
     def test_lacking_parent(self):
         with source_util.create_modules('_pkg.__init__', '_pkg.mod')as mapping:
-            loader = _bootstrap._PyPycFileLoader('_pkg.mod',
-                                                    mapping['_pkg.mod'], False)
+            loader = _bootstrap._SourceFileLoader('_pkg.mod',
+                                                    mapping['_pkg.mod'])
             module = loader.load_module('_pkg.mod')
             self.assertTrue('_pkg.mod' in sys.modules)
             check = {'__name__': '_pkg.mod', '__file__': mapping['_pkg.mod'],
@@ -63,8 +62,7 @@ class SimpleTest(unittest.TestCase):
 
     def test_module_reuse(self):
         with source_util.create_modules('_temp') as mapping:
-            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
-                                                    False)
+            loader = _bootstrap._SourceFileLoader('_temp', mapping['_temp'])
             module = loader.load_module('_temp')
             module_id = id(module)
             module_dict_id = id(module.__dict__)
@@ -74,7 +72,7 @@ class SimpleTest(unittest.TestCase):
             # everything that has happened above can be too fast;
             # force an mtime on the source that is guaranteed to be different
             # than the original mtime.
-            loader.source_mtime = self.fake_mtime(loader.source_mtime)
+            loader.path_mtime = self.fake_mtime(loader.path_mtime)
             module = loader.load_module('_temp')
             self.assertTrue('testing_var' in module.__dict__,
                          "'testing_var' not in "
@@ -94,8 +92,7 @@ class SimpleTest(unittest.TestCase):
                 setattr(orig_module, attr, value)
             with open(mapping[name], 'w') as file:
                 file.write('+++ bad syntax +++')
-            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
-                                                    False)
+            loader = _bootstrap._SourceFileLoader('_temp', mapping['_temp'])
             with self.assertRaises(SyntaxError):
                 loader.load_module(name)
             for attr in attributes:
@@ -106,8 +103,7 @@ class SimpleTest(unittest.TestCase):
         with source_util.create_modules('_temp') as mapping:
             with open(mapping['_temp'], 'w') as file:
                 file.write('=')
-            loader = _bootstrap._PyPycFileLoader('_temp', mapping['_temp'],
-                                                    False)
+            loader = _bootstrap._SourceFileLoader('_temp', mapping['_temp'])
             with self.assertRaises(SyntaxError):
                 loader.load_module('_temp')
             self.assertTrue('_temp' not in sys.modules)
@@ -116,7 +112,7 @@ class SimpleTest(unittest.TestCase):
 class BadBytecodeTest(unittest.TestCase):
 
     def import_(self, file, module_name):
-        loader = _bootstrap._PyPycFileLoader(module_name, file, False)
+        loader = self.loader(module_name, file)
         module = loader.load_module(module_name)
         self.assertTrue(module_name in sys.modules)
 
@@ -129,101 +125,156 @@ class BadBytecodeTest(unittest.TestCase):
         except KeyError:
             pass
         py_compile.compile(mapping[name])
-        bytecode_path = imp.cache_from_source(mapping[name])
-        with open(bytecode_path, 'rb') as file:
-            bc = file.read()
-        new_bc = manipulator(bc)
-        with open(bytecode_path, 'wb') as file:
-            if new_bc:
-                file.write(new_bc)
-        if del_source:
+        if not del_source:
+            bytecode_path = imp.cache_from_source(mapping[name])
+        else:
             os.unlink(mapping[name])
-            make_legacy_pyc(mapping[name])
+            bytecode_path = make_legacy_pyc(mapping[name])
+        if manipulator:
+            with open(bytecode_path, 'rb') as file:
+                bc = file.read()
+                new_bc = manipulator(bc)
+            with open(bytecode_path, 'wb') as file:
+                if new_bc is not None:
+                    file.write(new_bc)
         return bytecode_path
 
-    @source_util.writes_bytecode_files
-    def test_empty_file(self):
-        # When a .pyc is empty, regenerate it if possible, else raise
-        # ImportError.
+    def _test_empty_file(self, test, *, del_source=False):
         with source_util.create_modules('_temp') as mapping:
             bc_path = self.manipulate_bytecode('_temp', mapping,
-                                                lambda bc: None)
-            self.import_(mapping['_temp'], '_temp')
-            with open(bc_path, 'rb') as file:
-                self.assertGreater(len(file.read()), 8)
-            self.manipulate_bytecode('_temp', mapping, lambda bc: None,
-                                        del_source=True)
-            with self.assertRaises(ImportError):
-                self.import_(mapping['_temp'], '_temp')
+                                                lambda bc: b'',
+                                                del_source=del_source)
+            test('_temp', mapping, bc_path)
 
     @source_util.writes_bytecode_files
-    def test_partial_magic(self):
+    def _test_partial_magic(self, test, *, del_source=False):
         # When their are less than 4 bytes to a .pyc, regenerate it if
         # possible, else raise ImportError.
         with source_util.create_modules('_temp') as mapping:
             bc_path = self.manipulate_bytecode('_temp', mapping,
-                                                lambda bc: bc[:3])
-            self.import_(mapping['_temp'], '_temp')
-            with open(bc_path, 'rb') as file:
-                self.assertGreater(len(file.read()), 8)
-            self.manipulate_bytecode('_temp', mapping, lambda bc: bc[:3],
-                                        del_source=True)
+                                                lambda bc: bc[:3],
+                                                del_source=del_source)
+            test('_temp', mapping, bc_path)
+
+    def _test_magic_only(self, test, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bc_path = self.manipulate_bytecode('_temp', mapping,
+                                                lambda bc: bc[:4],
+                                                del_source=del_source)
+            test('_temp', mapping, bc_path)
+
+    def _test_partial_timestamp(self, test, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bc_path = self.manipulate_bytecode('_temp', mapping,
+                                                lambda bc: bc[:7],
+                                                del_source=del_source)
+            test('_temp', mapping, bc_path)
+
+    def _test_no_marshal(self, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bc_path = self.manipulate_bytecode('_temp', mapping,
+                                                lambda bc: bc[:8],
+                                                del_source=del_source)
+            file_path = mapping['_temp'] if not del_source else bc_path
+            with self.assertRaises(EOFError):
+                self.import_(file_path, '_temp')
+
+    def _test_non_code_marshal(self, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bytecode_path = self.manipulate_bytecode('_temp', mapping,
+                                    lambda bc: bc[:8] + marshal.dumps(b'abcd'),
+                                    del_source=del_source)
+            file_path = mapping['_temp'] if not del_source else bytecode_path
             with self.assertRaises(ImportError):
-                self.import_(mapping['_temp'], '_temp')
+                self.import_(file_path, '_temp')
+
+    def _test_bad_marshal(self, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bytecode_path = self.manipulate_bytecode('_temp', mapping,
+                                                lambda bc: bc[:8] + b'<test>',
+                                                del_source=del_source)
+            file_path = mapping['_temp'] if not del_source else bytecode_path
+            with self.assertRaises(ValueError):
+                self.import_(file_path, '_temp')
+
+    def _test_bad_magic(self, test, *, del_source=False):
+        with source_util.create_modules('_temp') as mapping:
+            bc_path = self.manipulate_bytecode('_temp', mapping,
+                                    lambda bc: b'\x00\x00\x00\x00' + bc[4:])
+            test('_temp', mapping, bc_path)
+
+
+class SourceLoaderBadBytecodeTest(BadBytecodeTest):
+
+    loader = _bootstrap._SourceFileLoader
+
+    @source_util.writes_bytecode_files
+    def test_empty_file(self):
+        # When a .pyc is empty, regenerate it if possible, else raise
+        # ImportError.
+        def test(name, mapping, bytecode_path):
+            self.import_(mapping[name], name)
+            with open(bytecode_path, 'rb') as file:
+                self.assertGreater(len(file.read()), 8)
+
+        self._test_empty_file(test)
+
+    def test_partial_magic(self):
+        def test(name, mapping, bytecode_path):
+            self.import_(mapping[name], name)
+            with open(bytecode_path, 'rb') as file:
+                self.assertGreater(len(file.read()), 8)
+
+        self._test_partial_magic(test)
 
     @source_util.writes_bytecode_files
     def test_magic_only(self):
         # When there is only the magic number, regenerate the .pyc if possible,
         # else raise EOFError.
-        with source_util.create_modules('_temp') as mapping:
-            bc_path = self.manipulate_bytecode('_temp', mapping,
-                                                lambda bc: bc[:4])
-            self.import_(mapping['_temp'], '_temp')
-            with open(bc_path, 'rb') as file:
+        def test(name, mapping, bytecode_path):
+            self.import_(mapping[name], name)
+            with open(bytecode_path, 'rb') as file:
                 self.assertGreater(len(file.read()), 8)
-            self.manipulate_bytecode('_temp', mapping, lambda bc: bc[:4],
-                                        del_source=True)
-            with self.assertRaises(EOFError):
-                self.import_(mapping['_temp'], '_temp')
+
+    @source_util.writes_bytecode_files
+    def test_bad_magic(self):
+        # When the magic number is different, the bytecode should be
+        # regenerated.
+        def test(name, mapping, bytecode_path):
+            self.import_(mapping[name], name)
+            with open(bytecode_path, 'rb') as bytecode_file:
+                self.assertEqual(bytecode_file.read(4), imp.get_magic())
+
+        self._test_bad_magic(test)
 
     @source_util.writes_bytecode_files
     def test_partial_timestamp(self):
         # When the timestamp is partial, regenerate the .pyc, else
         # raise EOFError.
-        with source_util.create_modules('_temp') as mapping:
-            bc_path = self.manipulate_bytecode('_temp', mapping,
-                                                lambda bc: bc[:7])
-            self.import_(mapping['_temp'], '_temp')
+        def test(name, mapping, bc_path):
+            self.import_(mapping[name], name)
             with open(bc_path, 'rb') as file:
                 self.assertGreater(len(file.read()), 8)
-            self.manipulate_bytecode('_temp', mapping, lambda bc: bc[:7],
-                                        del_source=True)
-            with self.assertRaises(EOFError):
-                self.import_(mapping['_temp'], '_temp')
 
     @source_util.writes_bytecode_files
     def test_no_marshal(self):
         # When there is only the magic number and timestamp, raise EOFError.
-        with source_util.create_modules('_temp') as mapping:
-            bc_path = self.manipulate_bytecode('_temp', mapping,
-                                                lambda bc: bc[:8])
-            with self.assertRaises(EOFError):
-                self.import_(mapping['_temp'], '_temp')
+        self._test_no_marshal()
 
     @source_util.writes_bytecode_files
-    def test_bad_magic(self):
-        # When the magic number is different, the bytecode should be
-        # regenerated.
-        with source_util.create_modules('_temp') as mapping:
-            bc_path = self.manipulate_bytecode('_temp', mapping,
-                                    lambda bc: b'\x00\x00\x00\x00' + bc[4:])
-            self.import_(mapping['_temp'], '_temp')
-            with open(bc_path, 'rb') as bytecode_file:
-                self.assertEqual(bytecode_file.read(4), imp.get_magic())
+    def test_non_code_marshal(self):
+        self._test_non_code_marshal()
+        # XXX ImportError when sourceless
+
+    # [bad marshal]
+    @source_util.writes_bytecode_files
+    def test_bad_marshal(self):
+        # Bad marshal data should raise a ValueError.
+        self._test_bad_marshal()
 
     # [bad timestamp]
     @source_util.writes_bytecode_files
-    def test_bad_bytecode(self):
+    def test_old_timestamp(self):
         # When the timestamp is older than the source, bytecode should be
         # regenerated.
         zeros = b'\x00\x00\x00\x00'
@@ -240,23 +291,6 @@ class BadBytecodeTest(unittest.TestCase):
                 bytecode_file.seek(4)
                 self.assertEqual(bytecode_file.read(4), source_timestamp)
 
-    # [bad marshal]
-    @source_util.writes_bytecode_files
-    def test_bad_marshal(self):
-        # Bad marshal data should raise a ValueError.
-        with source_util.create_modules('_temp') as mapping:
-            bytecode_path = imp.cache_from_source(mapping['_temp'])
-            source_mtime = os.path.getmtime(mapping['_temp'])
-            source_timestamp = importlib._w_long(source_mtime)
-            source_util.ensure_bytecode_path(bytecode_path)
-            with open(bytecode_path, 'wb') as bytecode_file:
-                bytecode_file.write(imp.get_magic())
-                bytecode_file.write(source_timestamp)
-                bytecode_file.write(b'AAAA')
-            with self.assertRaises(ValueError):
-                self.import_(mapping['_temp'], '_temp')
-            self.assertTrue('_temp' not in sys.modules)
-
     # [bytecode read-only]
     @source_util.writes_bytecode_files
     def test_read_only_bytecode(self):
@@ -279,9 +313,57 @@ class BadBytecodeTest(unittest.TestCase):
                 os.chmod(bytecode_path, stat.S_IWUSR)
 
 
+class SourcelessLoaderBadBytecodeTest(BadBytecodeTest):
+
+    loader = _bootstrap._SourcelessFileLoader
+
+    def test_empty_file(self):
+        def test(name, mapping, bytecode_path):
+            with self.assertRaises(ImportError):
+                self.import_(bytecode_path, name)
+
+        self._test_empty_file(test, del_source=True)
+
+    def test_partial_magic(self):
+        def test(name, mapping, bytecode_path):
+            with self.assertRaises(ImportError):
+                self.import_(bytecode_path, name)
+        self._test_partial_magic(test, del_source=True)
+
+    def test_magic_only(self):
+        def test(name, mapping, bytecode_path):
+            with self.assertRaises(EOFError):
+                self.import_(bytecode_path, name)
+
+        self._test_magic_only(test, del_source=True)
+
+    def test_bad_magic(self):
+        def test(name, mapping, bytecode_path):
+            with self.assertRaises(ImportError):
+                self.import_(bytecode_path, name)
+
+        self._test_bad_magic(test, del_source=True)
+
+    def test_partial_timestamp(self):
+        def test(name, mapping, bytecode_path):
+            with self.assertRaises(EOFError):
+                self.import_(bytecode_path, name)
+
+        self._test_partial_timestamp(test, del_source=True)
+
+    def test_no_marshal(self):
+        self._test_no_marshal(del_source=True)
+
+    def test_non_code_marshal(self):
+        self._test_non_code_marshal(del_source=True)
+
+
 def test_main():
     from test.support import run_unittest
-    run_unittest(SimpleTest, BadBytecodeTest)
+    run_unittest(SimpleTest,
+                 SourceLoaderBadBytecodeTest,
+                 SourcelessLoaderBadBytecodeTest
+                 )
 
 
 if __name__ == '__main__':
diff --git a/Lib/importlib/test/source/test_finder.py b/Lib/importlib/test/source/test_finder.py
index 1673669..12bab8f 100644
--- a/Lib/importlib/test/source/test_finder.py
+++ b/Lib/importlib/test/source/test_finder.py
@@ -34,7 +34,9 @@ class FinderTests(abc.FinderTests):
     """
 
     def import_(self, root, module):
-        finder = _bootstrap._PyPycFileFinder(root)
+        finder = _bootstrap._FileFinder(root,
+                                        _bootstrap._SourceFinderDetails(),
+                                        _bootstrap._SourcelessFinderDetails())
         return finder.find_module(module)
 
     def run_test(self, test, create=None, *, compile_=None, unlink=None):
@@ -116,7 +118,7 @@ class FinderTests(abc.FinderTests):
         # XXX This is not a blackbox test!
         name = '_temp'
         loader = self.run_test(name, {'{0}.__init__'.format(name), name})
-        self.assertTrue('__init__' in loader._base_path)
+        self.assertTrue('__init__' in loader.get_filename(name))
 
 
     def test_failure(self):
diff --git a/Lib/importlib/test/source/test_path_hook.py b/Lib/importlib/test/source/test_path_hook.py
index 3efb3be..8697f0c 100644
--- a/Lib/importlib/test/source/test_path_hook.py
+++ b/Lib/importlib/test/source/test_path_hook.py
@@ -8,9 +8,8 @@ class PathHookTest(unittest.TestCase):
     """Test the path hook for source."""
 
     def test_success(self):
-        # XXX Only work on existing directories?
         with source_util.create_modules('dummy') as mapping:
-            self.assertTrue(hasattr(_bootstrap._FileFinder(mapping['.root']),
+            self.assertTrue(hasattr(_bootstrap._file_path_hook(mapping['.root']),
                                  'find_module'))
 
 
diff --git a/Lib/importlib/test/source/test_source_encoding.py b/Lib/importlib/test/source/test_source_encoding.py
index 04aac24..794a3df 100644
--- a/Lib/importlib/test/source/test_source_encoding.py
+++ b/Lib/importlib/test/source/test_source_encoding.py
@@ -35,8 +35,8 @@ class EncodingTest(unittest.TestCase):
         with source_util.create_modules(self.module_name) as mapping:
             with open(mapping[self.module_name], 'wb') as file:
                 file.write(source)
-            loader = _bootstrap._PyPycFileLoader(self.module_name,
-                                       mapping[self.module_name], False)
+            loader = _bootstrap._SourceFileLoader(self.module_name,
+                                       mapping[self.module_name])
             return loader.load_module(self.module_name)
 
     def create_source(self, encoding):
@@ -97,8 +97,8 @@ class LineEndingTest(unittest.TestCase):
         with source_util.create_modules(module_name) as mapping:
             with open(mapping[module_name], 'wb') as file:
                 file.write(source)
-            loader = _bootstrap._PyPycFileLoader(module_name,
-                                                 mapping[module_name], False)
+            loader = _bootstrap._SourceFileLoader(module_name,
+                                                 mapping[module_name])
             return loader.load_module(module_name)
 
     # [cr]
diff --git a/Lib/test/test_runpy.py b/Lib/test/test_runpy.py
index 068eca9..94e47d6 100644
--- a/Lib/test/test_runpy.py
+++ b/Lib/test/test_runpy.py
@@ -6,7 +6,7 @@ import sys
 import re
 import tempfile
 import py_compile
-from test.support import forget, make_legacy_pyc, run_unittest, verbose
+from test.support import forget, make_legacy_pyc, run_unittest, unload, verbose
 from test.script_helper import (
     make_pkg, make_script, make_zip_pkg, make_zip_script, temp_dir)
 
@@ -174,6 +174,7 @@ class RunModuleTest(unittest.TestCase):
             __import__(mod_name)
             os.remove(mod_fname)
             make_legacy_pyc(mod_fname)
+            unload(mod_name)  # In case loader caches paths
             if verbose: print("Running from compiled:", mod_name)
             d2 = run_module(mod_name) # Read from bytecode
             self.assertIn("x", d2)
@@ -197,6 +198,7 @@ class RunModuleTest(unittest.TestCase):
             __import__(mod_name)
             os.remove(mod_fname)
             make_legacy_pyc(mod_fname)
+            unload(mod_name)  # In case loader caches paths
             if verbose: print("Running from compiled:", pkg_name)
             d2 = run_module(pkg_name) # Read from bytecode
             self.assertIn("x", d2)
@@ -252,6 +254,7 @@ from ..uncle.cousin import nephew
             __import__(mod_name)
             os.remove(mod_fname)
             make_legacy_pyc(mod_fname)
+            unload(mod_name)  # In case the loader caches paths
             if verbose: print("Running from compiled:", mod_name)
             d2 = run_module(mod_name, run_name=run_name) # Read from bytecode
             self.assertIn("__package__", d2)
@@ -405,7 +408,11 @@ argv0 = sys.argv[0]
 
 
 def test_main():
-    run_unittest(RunModuleCodeTest, RunModuleTest, RunPathTest)
+    run_unittest(
+                 RunModuleCodeTest,
+                 RunModuleTest,
+                 RunPathTest
+                 )
 
 if __name__ == "__main__":
     test_main()