From ee78a2b51cd9ede91bb780b71444119e1da19e4e Mon Sep 17 00:00:00 2001 From: Brett Cannon Date: Sat, 12 May 2012 17:43:17 -0400 Subject: Issue #13959: Introduce importlib.find_loader(). The long-term goal is to deprecate imp.find_module() in favour of this API, but it will take some time as some APIs explicitly return/use what imp.find_module() returns. --- Doc/library/importlib.rst | 14 ++++++++++++ Lib/importlib/__init__.py | 24 ++++++++++++++++++++ Lib/importlib/test/test_api.py | 50 +++++++++++++++++++++++++++++++++++++++++- Lib/pyclbr.py | 25 +++++++++++++-------- Misc/NEWS | 2 ++ 5 files changed, 105 insertions(+), 10 deletions(-) diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst index cac5251..0bc1b65 100644 --- a/Doc/library/importlib.rst +++ b/Doc/library/importlib.rst @@ -86,6 +86,20 @@ Functions that was imported (e.g. ``pkg.mod``), while :func:`__import__` returns the top-level package or module (e.g. ``pkg``). +.. function:: find_loader(name, path=None) + + Find the loader for a module, optionally within the specified *path*. If the + module is in :attr:`sys.modules`, then ``sys.modules[name].__loader__`` is + returned (unless the loader would be ``None``, in which case + :exc:`ValueError` is raised). Otherwise a search using :attr:`sys.meta_path` + is done. ``None`` is returned if no loader is found. + + A dotted name does not have its parent's implicitly imported. If that is + desired (although not nessarily required to find the loader, it will most + likely be needed if the loader actually is used to load the module), then + you will have to import the packages containing the module prior to calling + this function. + .. function:: invalidate_caches() Invalidate the internal caches of the finders stored at diff --git a/Lib/importlib/__init__.py b/Lib/importlib/__init__.py index 57fb284..90e163c 100644 --- a/Lib/importlib/__init__.py +++ b/Lib/importlib/__init__.py @@ -29,6 +29,30 @@ def invalidate_caches(): finder.invalidate_caches() +def find_loader(name, path=None): + """Find the loader for the specified module. + + First, sys.modules is checked to see if the module was already imported. If + so, then sys.modules[name].__loader__ is returned. If that happens to be + set to None, then ValueError is raised. If the module is not in + sys.modules, then sys.meta_path is searched for a suitable loader with the + value of 'path' given to the finders. None is returned if no loader could + be found. + + Dotted names do not have their parent packages implicitly imported. + + """ + try: + loader = sys.modules[name].__loader__ + if loader is None: + raise ValueError('{}.__loader__ is None'.format(name)) + else: + return loader + except KeyError: + pass + return _bootstrap._find_module(name, path) + + def import_module(name, package=None): """Import a module. diff --git a/Lib/importlib/test/test_api.py b/Lib/importlib/test/test_api.py index cc147c2..b7d6cb4 100644 --- a/Lib/importlib/test/test_api.py +++ b/Lib/importlib/test/test_api.py @@ -85,6 +85,54 @@ class ImportModuleTests(unittest.TestCase): self.assertEqual(b_load_count, 1) +class FindLoaderTests(unittest.TestCase): + + class FakeMetaFinder: + @staticmethod + def find_module(name, path=None): return name, path + + def test_sys_modules(self): + # If a module with __loader__ is in sys.modules, then return it. + name = 'some_mod' + with util.uncache(name): + module = imp.new_module(name) + loader = 'a loader!' + module.__loader__ = loader + sys.modules[name] = module + found = importlib.find_loader(name) + self.assertEqual(loader, found) + + def test_sys_modules_loader_is_None(self): + # If sys.modules[name].__loader__ is None, raise ValueError. + name = 'some_mod' + with util.uncache(name): + module = imp.new_module(name) + module.__loader__ = None + sys.modules[name] = module + with self.assertRaises(ValueError): + importlib.find_loader(name) + + def test_success(self): + # Return the loader found on sys.meta_path. + name = 'some_mod' + with util.uncache(name): + with util.import_state(meta_path=[self.FakeMetaFinder]): + self.assertEqual((name, None), importlib.find_loader(name)) + + def test_success_path(self): + # Searching on a path should work. + name = 'some_mod' + path = 'path to some place' + with util.uncache(name): + with util.import_state(meta_path=[self.FakeMetaFinder]): + self.assertEqual((name, path), + importlib.find_loader(name, path)) + + def test_nothing(self): + # None is returned upon failure to find a loader. + self.assertIsNone(importlib.find_loader('nevergoingtofindthismodule')) + + class InvalidateCacheTests(unittest.TestCase): def test_method_called(self): @@ -114,7 +162,7 @@ class InvalidateCacheTests(unittest.TestCase): def test_main(): from test.support import run_unittest - run_unittest(ImportModuleTests) + run_unittest(ImportModuleTests, FindLoaderTests, InvalidateCacheTests) if __name__ == '__main__': diff --git a/Lib/pyclbr.py b/Lib/pyclbr.py index 52cbdd5..4cd85b9 100644 --- a/Lib/pyclbr.py +++ b/Lib/pyclbr.py @@ -39,8 +39,10 @@ Instances of this class have the following instance variables: lineno -- the line in the file on which the class statement occurred """ +import io +import os import sys -import imp +import importlib import tokenize from token import NAME, DEDENT, OP from operator import itemgetter @@ -133,19 +135,24 @@ def _readmodule(module, path, inpackage=None): # Search the path for the module f = None if inpackage is not None: - f, fname, (_s, _m, ty) = imp.find_module(module, path) + search_path = path else: - f, fname, (_s, _m, ty) = imp.find_module(module, path + sys.path) - if ty == imp.PKG_DIRECTORY: - dict['__path__'] = [fname] - path = [fname] + path - f, fname, (_s, _m, ty) = imp.find_module('__init__', [fname]) + search_path = path + sys.path + loader = importlib.find_loader(fullmodule, search_path) + fname = loader.get_filename(fullmodule) _modules[fullmodule] = dict - if ty != imp.PY_SOURCE: + if loader.is_package(fullmodule): + dict['__path__'] = [os.path.dirname(fname)] + try: + source = loader.get_source(fullmodule) + if source is None: + return dict + except (AttributeError, ImportError): # not Python source, can't do anything with this module - f.close() return dict + f = io.StringIO(source) + stack = [] # stack of (class, indent) pairs g = tokenize.generate_tokens(f.readline) diff --git a/Misc/NEWS b/Misc/NEWS index 78a5ef9..a7d1b44 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -23,6 +23,8 @@ Core and Builtins Library ------- +- Issue #13959: Introduce importlib.find_loader(). + - Issue #14082: shutil.copy2() now copies extended attributes, if possible. Patch by Hynek Schlawack. -- cgit v0.12