paths.

Thanks to Eric Snow for taking an initial stab at the implementation.

the UNC path. Also clean up sys.path and invalidate finder caches.

Thanks to Vinay Sajip for spotting the use of the wrong path.

separators.

for performance. While get_magic() could move to Lib/imp.py, having to
support PyImport_GetMagicNumber() would lead to equal, if not more, C
code than sticking with the status quo.

Issue #14339: Improve speed of bin, oct and hex builtins.  Patch by Serhiy Storchaka (with minor modifications).

as found in sys.modules and not as what the loader returns (even
though it is required to by PEP 302).

importlib.test.import_ using builtins.__import__() instead of just the
relative import tests.

extension modules.

in Python/dynload_shlibs.c.

This should fix the remaining importlib test failure on Windows.
Support in AIX and HP-UX will be in a separate checkin.

this is more readable.

  1) Rename _mpd_qbarrett_divmod into _mpd_base_ndivmod: The function is
     only marginally related to either Barrett's algorithm or to the version
     in Hasselstrom's paper.

  2) In places where the proof assumes exact operations, use new versions of
     add/sub/multiply that set NaN/Invalid_operation if this condition is
     not met. According to the proof this cannot happen, so this should be
     regarded as an extra safety net.

  3) Raise Division_impossible for operands with a number of digits greater
     than MPD_MAX_PREC. This facilitates the audit of the function and can
     practically only occur in the 32-bit version under conditions where
     a MemoryError is already imminent.

  4) Use _mpd_qmul() in places where the result can exceed MPD_MAX_PREC in
     a well defined manner.

  5) Test for mpd_isspecial(qq) in a place where the addition of one
     can theoretically trigger a Malloc_error.

  6) Remove redundant code in _mpd_qdivmod().

  7) Add many comments.

tokenizer.detect_encoding() (when available).

#14629 changed the message.

the file suffix's case into account, even when doing a case-sensitive
import.

sure finders from importlib are used instead of _frozen_importlib.

if the first two lines have non-UTF-8 characters without an encoding declaration.

Issue #14308: Fix an exception when a dummy thread is in the threading module's active list after a fork().

Issue #14308: Fix an exception when a "dummy" thread is in the threading module's active list after a fork().