A bunch of code currently uses PyInterpreterState.modules directly instead of PyImport_GetModuleDict(). This complicates efforts to make changes relative to sys.modules. This patch switches to using PyImport_GetModuleDict() uniformly. Also, a number of related uses of sys.modules are updated for uniformity for the same reason.
Note that this code was already reviewed and merged as part of #1638. I reverted that and am now splitting it up into more focused parts.
PR #1638, for bpo-28411, causes problems in some (very) edge cases. Until that gets sorted out, we're reverting the merge. PR #3506, a fix on top of #1638, is also getting reverted.
Known limitations of the current implementation:
- documentation changes are incomplete
- there's a reference leak I haven't tracked down yet
The leak is most visible by running:
./python -m test -R3:3 test_importlib
However, you can also see it by running:
./python -X showrefcount
Importing the array or _testmultiphase modules, and
then deleting them from both sys.modules and the local
namespace shows significant increases in the total
number of active references each cycle. By contrast,
with _testcapi (which continues to use single-phase
initialisation) the global refcounts stabilise after
a couple of cycles.
importlib._bootstrap is now frozen into Python/importlib.h and stored
as _frozen_importlib in sys.modules. Py_Initialize() loads the frozen
code along with sys and imp and then uses _frozen_importlib._install()
to set builtins.__import__() w/ _frozen_importlib.__import__().
The name must be encodable to ASCII because dynamic module must have a function
called "PyInit_NAME", they are written in C, and the C language doesn't accept
non-ASCII identifiers.
- is_builtin(), init_builtin(), load_builtin() and other builtin related
functions use Unicode strings, instead of byte strings
- Rename _PyImport_FixupExtensionUnicode() to _PyImport_FixupExtensionObject()
- Rename _PyImport_FindExtensionUnicode() to _PyImport_FindExtensionObject()
* Rename _PyImport_FindExtension() to _PyImport_FindExtensionUnicode():
the filename becomes a Unicode object instead of byte string
* Rename _PyImport_FixupExtension() to _PyImport_FixupExtensionUnicode():
the filename becomes a Unicode object instead of byte string
