Add a keyword-only *follow_symlinks* parameter to `pathlib.Path.glob()` and
`rglob()`, defaulting to false. When set to true, symlinks to directories
are followed as if they were directories.

Previously these methods followed symlinks except when evaluating "`**`"
wildcards; on Windows they returned paths in filesystem casing except when
evaluating non-wildcard tokens. Both these problems are solved here. This
will allow us to address pythonGH-102613 and pythonGH-81079 in future commits.

Stop de-duplicating results in `_RecursiveWildcardSelector`. A new
`_DoubleRecursiveWildcardSelector` class is introduced which performs
de-duplication, but this is used _only_ for patterns with multiple
non-adjacent `**` segments, such as `path.glob('**/foo/**')`. By avoiding
the use of a set, `PurePath.__hash__()` is not called, and so paths do not
need to be parsed and (case-) normalised.

Also merge adjacent '**' segments in patterns.

Stop de-duplicating results in `_RecursiveWildcardSelector`. A new
`_DoubleRecursiveWildcardSelector` class is introduced which performs
de-duplication, but this is used _only_ for patterns with multiple
non-adjacent `**` segments, such as `path.glob('**/foo/**')`. By avoiding
the use of a set, `PurePath.__hash__()` is not called, and so paths do not
need to be stringified and case-normalised.

Also merge adjacent '**' segments in patterns.

…nGH-104244)

Stop de-duplicating results in `_RecursiveWildcardSelector`. A new
`_DoubleRecursiveWildcardSelector` class is introduced which performs
de-duplication, but this is used _only_ for patterns with multiple
non-adjacent `**` segments, such as `path.glob('**/foo/**')`. By avoiding
the use of a set, `PurePath.__hash__()` is not called, and so paths do not
need to be stringified and case-normalised.

Also merge adjacent '**' segments in patterns.

* main: (47 commits)
  pythongh-97696 Remove unnecessary check for eager_start kwarg (python#104188)
  pythonGH-104308: socket.getnameinfo should release the GIL (python#104307)
  pythongh-104310: Add importlib.util.allowing_all_extensions() (pythongh-104311)
  pythongh-99113: A Per-Interpreter GIL! (pythongh-104210)
  pythonGH-104284: Fix documentation gettext build (python#104296)
  pythongh-89550: Buffer GzipFile.write to reduce execution time by ~15% (python#101251)
  pythongh-104223: Fix issues with inheriting from buffer classes (python#104227)
  pythongh-99108: fix typo in Modules/Setup (python#104293)
  pythonGH-104145: Use fully-qualified cross reference types for the bisect module (python#104172)
  pythongh-103193: Improve `getattr_static` test coverage (python#104286)
  Trim trailing whitespace and test on CI (python#104275)
  pythongh-102500: Remove mention of bytes shorthand (python#104281)
  pythongh-97696: Improve and fix documentation for asyncio eager tasks (python#104256)
  pythongh-99108: Replace SHA3 implementation HACL* version (python#103597)
  pythongh-104273: Remove redundant len() calls in argparse function (python#104274)
  pythongh-64660: Don't hardcode Argument Clinic return converter result variable name (python#104200)
  pythongh-104265 Disallow instantiation of `_csv.Reader` and `_csv.Writer` (python#104266)
  pythonGH-102613: Improve performance of `pathlib.Path.rglob()` (pythonGH-104244)
  pythongh-103650: Fix perf maps address format (python#103651)
  pythonGH-89812: Churn `pathlib.Path` methods (pythonGH-104243)
  ...

Use `Path.walk()` to implement the recursive wildcard `**`. This method
uses an iterative (rather than recursive) walk - see pythonGH-100282.

Use `Path.walk()` to implement the recursive wildcard `**`. This method
uses an iterative (rather than recursive) walk - see GH-100282.

This commit replaces selector classes with selector functions. These
generators directly yield results rather calling through to their
successor. A new internal `Path._glob()` takes care to chain these
generators together, which simplifies the lazy algorithm and slightly
improves performance.

* main:
  pythonGH-104510: Fix refleaks in `_io` base types (python#104516)
  pythongh-104539: Fix indentation error in logging.config.rst (python#104545)
  pythongh-104050: Don't star-import 'types' in Argument Clinic (python#104543)
  pythongh-104050: Add basic typing to CConverter in clinic.py (python#104538)
  pythongh-64595: Fix write file logic in Argument Clinic (python#104507)
  pythongh-104523: Inline minimal PGO rules (python#104524)
  pythongh-103861: Fix Zip64 extensions not being properly applied in some cases (python#103863)
  pythongh-69152: add method get_proxy_response_headers to HTTPConnection class (python#104248)
  pythongh-103763: Implement PEP 695 (python#103764)
  pythongh-104461: Run tkinter test_configure_screen on X11 only (pythonGH-104462)
  pythongh-104469: Convert _testcapi/watchers.c to use Argument Clinic (python#104503)
  pythongh-104482: Fix error handling bugs in ast.c (python#104483)
  pythongh-104341: Adjust tstate_must_exit() to Respect Interpreter Finalization (pythongh-104437)
  pythonGH-102613: Fix recursion error from `pathlib.Path.glob()` (pythonGH-104373)

This commit introduces a 'walk-and-match' strategy for handling glob patterns that include a non-terminal `**` wildcard, such as `**/*.py`. For this example, the previous implementation recursively walked directories using `os.scandir()` when it expanded the `**` component, and then **scanned those same directories again** when expanded the `*.py` component. This is wasteful.

In the new implementation, any components following a `**` wildcard are used to build a `re.Pattern` object, which is used to filter the results of the recursive walk. A pattern like `**/*.py` uses half the number of `os.scandir()` calls; a pattern like `**/*/*.py` a third, etc.

This new algorithm does not apply if either:

1. The *follow_symlinks* argument is set to `None` (its default), or
2. The pattern contains `..` components.

In these cases we fall back to the old implementation.

This commit also replaces selector classes with selector functions. These generators directly yield results rather calling through to their successors. A new internal `Path._glob()` method takes care to chain these generators together, which simplifies the lazy algorithm and slightly improves performance. It should also be easier to understand and maintain.

…er Coverage

…erage (#105744)

…er Coverage (pythonGH-105744)

(cherry picked from commit 4e80082)

Co-authored-by: Łukasz Langa <[email protected]>

…der Coverage (GH-105744) (#105749)

gh-102613: Bump recursion limit to fix running test_pathlib under Coverage (GH-105744)
(cherry picked from commit 4e80082)

Co-authored-by: Łukasz Langa <[email protected]>