From 3644456720cf6ea3579551e5ed7586f3bfdd7041 Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Tue, 3 Oct 2023 14:48:53 +0100
Subject: [PATCH] Defer importing `warnings` in several modules

---
 Lib/hmac.py             | 3 ++-
 Lib/pathlib.py          | 5 ++++-
 Lib/wsgiref/validate.py | 4 +++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Lib/hmac.py b/Lib/hmac.py
index 8b4f920db954ca8..163c98245031226 100644
--- a/Lib/hmac.py
+++ b/Lib/hmac.py
@@ -3,7 +3,6 @@
 Implements the HMAC algorithm as described by RFC 2104.
 """
 
-import warnings as _warnings
 try:
     import _hashlib as _hashopenssl
 except ImportError:
@@ -84,11 +83,13 @@ def _init_old(self, key, msg, digestmod):
         if hasattr(self._inner, 'block_size'):
             blocksize = self._inner.block_size
             if blocksize < 16:
+                import warnings as _warnings
                 _warnings.warn('block_size of %d seems too small; using our '
                                'default of %d.' % (blocksize, self.blocksize),
                                RuntimeWarning, 2)
                 blocksize = self.blocksize
         else:
+            import warnings as _warnings
             _warnings.warn('No block_size attribute on given digest object; '
                            'Assuming %d.' % (self.blocksize),
                            RuntimeWarning, 2)
diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index 9e6d0754eccf3ea..762fe7b5ea689d7 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -14,7 +14,6 @@
 import posixpath
 import re
 import sys
-import warnings
 from _collections_abc import Sequence
 from errno import ENOENT, ENOTDIR, EBADF, ELOOP, EINVAL
 from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO
@@ -643,6 +642,7 @@ def relative_to(self, other, /, *_deprecated, walk_up=False):
         the path.
         """
         if _deprecated:
+            import warnings
             msg = ("support for supplying more than one positional argument "
                    "to pathlib.PurePath.relative_to() is deprecated and "
                    "scheduled for removal in Python {remove}")
@@ -665,6 +665,7 @@ def is_relative_to(self, other, /, *_deprecated):
         """Return True if the path is relative to another path or False.
         """
         if _deprecated:
+            import warnings
             msg = ("support for supplying more than one argument to "
                    "pathlib.PurePath.is_relative_to() is deprecated and "
                    "scheduled for removal in Python {remove}")
@@ -1115,6 +1116,7 @@ def _glob(self, pattern, case_sensitive, follow_symlinks):
             # GH-65238: pathlib doesn't preserve trailing slash. Add it back.
             pattern_parts.append('')
         if pattern_parts[-1] == '**':
+            import warnings
             # GH-70303: '**' only matches directories. Add trailing slash.
             warnings.warn(
                 "Pattern ending '**' will match files and directories in a "
@@ -1445,6 +1447,7 @@ class Path(_PathBase):
 
     def __init__(self, *args, **kwargs):
         if kwargs:
+            import warnings
             msg = ("support for supplying keyword arguments to pathlib.PurePath "
                    "is deprecated and scheduled for removal in Python {remove}")
             warnings._deprecated("pathlib.PurePath(**kwargs)", msg, remove=(3, 14))
diff --git a/Lib/wsgiref/validate.py b/Lib/wsgiref/validate.py
index 1a1853cd63a0d2a..2ad1a85e6d93901 100644
--- a/Lib/wsgiref/validate.py
+++ b/Lib/wsgiref/validate.py
@@ -113,7 +113,6 @@
 
 import re
 import sys
-import warnings
 
 header_re = re.compile(r'^[a-zA-Z][a-zA-Z0-9\-_]*$')
 bad_header_value_re = re.compile(r'[\000-\037]')
@@ -310,6 +309,7 @@ def check_environ(environ):
             "(use %s instead)" % (key, key[5:]))
 
     if 'QUERY_STRING' not in environ:
+        import warnings
         warnings.warn(
             'QUERY_STRING is not in the WSGI environment; the cgi '
             'module will use sys.argv when this variable is missing, '
@@ -335,6 +335,7 @@ def check_environ(environ):
     # @@: these need filling out:
     if environ['REQUEST_METHOD'] not in (
         'GET', 'HEAD', 'POST', 'OPTIONS', 'PATCH', 'PUT', 'DELETE', 'TRACE'):
+        import warnings
         warnings.warn(
             "Unknown REQUEST_METHOD: %r" % environ['REQUEST_METHOD'],
             WSGIWarning)
@@ -378,6 +379,7 @@ def check_status(status):
     status_int = int(status_code)
     assert_(status_int >= 100, "Status code is invalid: %r" % status_int)
     if len(status) < 4 or status[3] != ' ':
+        import warnings
         warnings.warn(
             "The status string (%r) should be a three-digit integer "
             "followed by a single space and a status explanation"