Issue #20426: When passing the re.DEBUG flag, re.compile() displays the debug output every time it is called, regardless of the compilation cache.

Improved error handling in variables-related commands.

exprlong() and exprboolean().

from the old green snake to the new new blue and yellow snakes.

Patch by OSAMU NAKAMURA.

which are at least as efficient. On Py3, unpacking exceptions never works.

is present.

successful when called during nulling out of modules during shutdown.
Misleading exception no longer raised when resource warning is emitted
during shutdown.

arguments.  Patch by Glenn Langford.

Patch by Nikolaus Rath.

make it actually gives some help when clicked. Patch by Guilherme Simões.

removed even for bound methods. (Inspect.signature does, see 20401.)

Original patch by Serhiy Storchaka.

Based on patch by Claudiu Popa.

codecs.StreamReader returned incomplete data when were called after
readline() or read(size).  Based on patch by Amaury Forgeot d'Arc.

http.server, imghdr, mailcap, mimetypes, xml.etree.

towards zero

On Windows os.open() error message doesn't contain file name.

- Alex J Burke noticed a debugging raise in the commit that
  fixed the original bug reported in issue 20317
- this showed that multiple iterations through the affected
  loop wasn't actually being tested