gh-103977: compile re expressions in platform.py only if required

Lib/platform.py

@@ -136,11 +136,11 @@
  'pl': 200, 'p': 200,
 }
 
-_component_re = re.compile(r'([0-9]+|[._+-])')
 
 def _comparable_version(version):
+ component_re = re.compile(r'([0-9]+|[._+-])')
  result = []
- for v in _component_re.split(version):
+ for v in component_re.split(version):
  if v not in '._+-':
  try:
  v = int(v, 10)
@@ -152,11 +152,6 @@ def _comparable_version(version):
 
 ### Platform specific APIs
 
-_libc_search = re.compile(b'(__libc_init)'
- b'|'
- b'(GLIBC_([0-9.]+))'
- b'|'
- br'(libc(_\w+)?\.so(?:\.(\d[0-9.]*))?)', re.ASCII)
 
 def libc_ver(executable=None, lib='', version='', chunksize=16384):
 
@@ -190,6 +185,12 @@ def libc_ver(executable=None, lib='', version='', chunksize=16384):
  # sys.executable is not set.
  return lib, version
 
+ libc_search = re.compile(b'(__libc_init)'
+ b'|'
+ b'(GLIBC_([0-9.]+))'
+ b'|'
+ br'(libc(_\w+)?\.so(?:\.(\d[0-9.]*))?)', re.ASCII)
+
  V = _comparable_version
  # We use os.path.realpath()
  # here to work around problems with Cygwin not being
@@ -200,7 +201,7 @@ def libc_ver(executable=None, lib='', version='', chunksize=16384):
  pos = 0
  while pos < len(binary):
  if b'libc' in binary or b'GLIBC' in binary:
- m = _libc_search.search(binary, pos)
+ m = libc_search.search(binary, pos)
  else:
  m = None
  if not m or m.end() == len(binary):
@@ -247,9 +248,6 @@ def _norm_version(version, build=''):
  version = '.'.join(strings[:3])
  return version
 
-_ver_output = re.compile(r'(?:([\w ]+) ([\w.]+) '
- r'.*'
- r'\[.* ([\d.]+)\])')
 
 # Examples of VER command output:
 #
@@ -295,9 +293,13 @@ def _syscmd_ver(system='', release='', version='',
  else:
  return system, release, version
 
+ ver_output = re.compile(r'(?:([\w ]+) ([\w.]+) '
+ r'.*'
+ r'\[.* ([\d.]+)\])')
+
  # Parse the output
  info = info.strip()
- m = _ver_output.match(info)
+ m = ver_output.match(info)
  if m is not None:
  system, release, version = m.groups()
  # Strip trailing dots from version and release
@@ -1033,18 +1035,6 @@ def processor():
 
 ### Various APIs for extracting information from sys.version
 
-_sys_version_parser = re.compile(
- r'([\w.+]+)\s*' # "version<space>"
- r'\(#?([^,]+)' # "(#buildno"
- r'(?:,\s*([\w ]*)' # ", builddate"
- r'(?:,\s*([\w :]*))?)?\)\s*' # ", buildtime)<space>"
- r'\[([^\]]+)\]?', re.ASCII) # "[compiler]"
-
-_pypy_sys_version_parser = re.compile(
- r'([\w.+]+)\s*'
- r'\(#?([^,]+),\s*([\w ]+),\s*([\w :]+)\)\s*'
- r'\[PyPy [^\]]+\]?')
-
 _sys_version_cache = {}
 
 def _sys_version(sys_version=None):
@@ -1076,10 +1066,17 @@ def _sys_version(sys_version=None):
  if result is not None:
  return result
 
+ sys_version_parser = re.compile(
+ r'([\w.+]+)\s*' # "version<space>"
+ r'\(#?([^,]+)' # "(#buildno"
+ r'(?:,\s*([\w ]*)' # ", builddate"
+ r'(?:,\s*([\w :]*))?)?\)\s*' # ", buildtime)<space>"
+ r'\[([^\]]+)\]?', re.ASCII) # "[compiler]"
+
  if sys.platform.startswith('java'):
  # Jython
  name = 'Jython'
- match = _sys_version_parser.match(sys_version)
+ match = sys_version_parser.match(sys_version)
  if match is None:
  raise ValueError(
  'failed to parse Jython sys.version: %s' %
@@ -1091,8 +1088,13 @@ def _sys_version(sys_version=None):
 
  elif "PyPy" in sys_version:
  # PyPy
+ pypy_sys_version_parser = re.compile(
+ r'([\w.+]+)\s*'
+ r'\(#?([^,]+),\s*([\w ]+),\s*([\w :]+)\)\s*'
+ r'\[PyPy [^\]]+\]?')
+
  name = "PyPy"
- match = _pypy_sys_version_parser.match(sys_version)
+ match = pypy_sys_version_parser.match(sys_version)
  if match is None:
  raise ValueError("failed to parse PyPy sys.version: %s" %
  repr(sys_version))
@@ -1101,7 +1103,7 @@ def _sys_version(sys_version=None):
 
  else:
  # CPython
- match = _sys_version_parser.match(sys_version)
+ match = sys_version_parser.match(sys_version)
  if match is None:
  raise ValueError(
  'failed to parse CPython sys.version: %s' %
@@ -1290,13 +1292,6 @@ def platform(aliased=False, terse=False):
 ### freedesktop.org os-release standard
 # https://www.freedesktop.org/software/systemd/man/os-release.html
 
-# NAME=value with optional quotes (' or "). The regular expression is less
-# strict than shell lexer, but that's ok.
-_os_release_line = re.compile(
- "^(?P<name>[a-zA-Z0-9_]+)=(?P<quote>[\"\']?)(?P<value>.*)(?P=quote)$"
-)
-# unescape five special characters mentioned in the standard
-_os_release_unescape = re.compile(r"\\([\\\$\"\'`])")
 # /etc takes precedence over /usr/lib
 _os_release_candidates = ("/etc/os-release", "/usr/lib/os-release")
 _os_release_cache = None
@@ -1311,10 +1306,18 @@ def _parse_os_release(lines):
  "PRETTY_NAME": "Linux",
  }
 
+ # NAME=value with optional quotes (' or "). The regular expression is less
+ # strict than shell lexer, but that's ok.
+ os_release_line = re.compile(
+ "^(?P<name>[a-zA-Z0-9_]+)=(?P<quote>[\"\']?)(?P<value>.*)(?P=quote)$"
+ )
+ # unescape five special characters mentioned in the standard
+ os_release_unescape = re.compile(r"\\([\\\$\"\'`])")
+
  for line in lines:
- mo = _os_release_line.match(line)
+ mo = os_release_line.match(line)
  if mo is not None:
- info[mo.group('name')] = _os_release_unescape.sub(
+ info[mo.group('name')] = os_release_unescape.sub(
  r"\1", mo.group('value')
  )
 

Misc/NEWS.d/next/Library/2023-04-28-19-08-50.gh-issue-103977.msF70A.rst

@@ -0,0 +1 @@
+Improve import time of :mod:`platform` module.