Issue #21313: Tolerate truncated buildinfo in sys.version
diff --git a/Lib/platform.py b/Lib/platform.py
index 3cf2303..63455ce 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -1314,9 +1314,11 @@
 ### Various APIs for extracting information from sys.version
 
 _sys_version_parser = re.compile(
-    r'([\w.+]+)\s*'
-    '\(#?([^,]+),\s*([\w ]+),\s*([\w :]+)\)\s*'
-    '\[([^\]]+)\]?')
+    r'([\w.+]+)\s*'  # "version<space>"
+    r'\(#?([^,]+)'  # "(#buildno"
+    r'(?:,\s*([\w ]*)'  # ", builddate"
+    r'(?:,\s*([\w :]*))?)?\)\s*'  # ", buildtime)<space>"
+    r'\[([^\]]+)\]?')  # "[compiler]"
 
 _ironpython_sys_version_parser = re.compile(
     r'IronPython\s*'
@@ -1395,6 +1397,8 @@
                 'failed to parse Jython sys.version: %s' %
                 repr(sys_version))
         version, buildno, builddate, buildtime, _ = match.groups()
+        if builddate is None:
+            builddate = ''
         compiler = sys.platform
 
     elif "PyPy" in sys_version:
@@ -1417,7 +1421,10 @@
         version, buildno, builddate, buildtime, compiler = \
               match.groups()
         name = 'CPython'
-        builddate = builddate + ' ' + buildtime
+        if builddate is None:
+            builddate = ''
+        elif buildtime:
+            builddate = builddate + ' ' + buildtime
 
     if hasattr(sys, 'subversion'):
         # sys.subversion was added in Python 2.5
diff --git a/Lib/test/test_platform.py b/Lib/test/test_platform.py
index 331995f..f754550 100644
--- a/Lib/test/test_platform.py
+++ b/Lib/test/test_platform.py
@@ -67,6 +67,22 @@
              ('IronPython', '1.0.60816', '', '', '', '', '.NET 2.0.50727.42')),
             ('IronPython 1.0 (1.0.61005.1977) on .NET 2.0.50727.42',
              ('IronPython', '1.0.0', '', '', '', '', '.NET 2.0.50727.42')),
+            ('2.4.3 (truncation, date, t) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', 'date t', 'GCC')),
+            ('2.4.3 (truncation, date, ) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', 'date', 'GCC')),
+            ('2.4.3 (truncation, date,) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', 'date', 'GCC')),
+            ('2.4.3 (truncation, date) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', 'date', 'GCC')),
+            ('2.4.3 (truncation, d) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', 'd', 'GCC')),
+            ('2.4.3 (truncation, ) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', '', 'GCC')),
+            ('2.4.3 (truncation,) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', '', 'GCC')),
+            ('2.4.3 (truncation) \n[GCC]',
+             ('CPython', '2.4.3', '', '', 'truncation', '', 'GCC')),
             ):
             # branch and revision are not "parsed", but fetched
             # from sys.subversion.  Ignore them
diff --git a/Misc/NEWS b/Misc/NEWS
index e785e6a..d555bf5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -92,6 +92,9 @@
 Library
 -------
 
+- Issue #21313: Fix the "platform" module to tolerate when sys.version
+  contains truncated build information.
+
 - Issue #27211: Fix possible memory corruption in io.IOBase.readline().
 
 - Issue #27114: Fix SSLContext._load_windows_store_certs fails with