[Python-checkins] bpo-26544: Get rid of dependence from distutils in platform. (GH-8356) (GH-8952)

[Victor Stinner]

https://github.com/python/cpython/commit/9734024ec65311e33936faa83fb1cb249ef0de9d
commit: 9734024ec65311e33936faa83fb1cb249ef0de9d
branch: 2.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Victor Stinner <vstinner at redhat.com>
date: 2018-09-05T16:46:26+02:00
summary:

bpo-26544: Get rid of dependence from distutils in platform. (GH-8356) (GH-8952)

(cherry picked from commit 7d81e8f5995df6980a1a02923e224a481375f130)

Co-authored-by: Serhiy Storchaka <storchaka at gmail.com>

files:
M Lib/platform.py

diff --git a/Lib/platform.py b/Lib/platform.py
index 44a612b28fce..62a5476a8f4d 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -132,6 +132,35 @@
         # Standard Unix uses /dev/null
         DEV_NULL = '/dev/null'
 
+# Helper for comparing two version number strings.
+# Based on the description of the PHP's version_compare():
+# http://php.net/manual/en/function.version-compare.php
+
+_ver_stages = {
+    # any string not found in this dict, will get 0 assigned
+    'dev': 10,
+    'alpha': 20, 'a': 20,
+    'beta': 30, 'b': 30,
+    'c': 40,
+    'RC': 50, 'rc': 50,
+    # number, will get 100 assigned
+    'pl': 200, 'p': 200,
+}
+
+_component_re = re.compile(r'([0-9]+|[._+-])')
+
+def _comparable_version(version):
+    result = []
+    for v in _component_re.split(version):
+        if v not in '._+-':
+            try:
+                v = int(v, 10)
+                t = 100
+            except ValueError:
+                t = _ver_stages.get(v, 0)
+            result.extend((t, v))
+    return result
+
 ### Platform specific APIs
 
 _libc_search = re.compile(r'(__libc_init)'
@@ -155,7 +184,7 @@ def libc_ver(executable=sys.executable,lib='',version='', chunksize=2048):
         The file is read and scanned in chunks of chunksize bytes.
 
     """
-    from distutils.version import LooseVersion as V
+    V = _comparable_version
     if hasattr(os.path, 'realpath'):
         # Python 2.2 introduced os.path.realpath(); it is used
         # here to work around problems with Cygwin not being