Fix #9923: mailcap now uses the OS path separator for the MAILCAP envvar. Not backported, since it could break cases where people worked around the old POSIX-specific behaviour on non-POSIX platforms.

Lib/mailcap.py

@@ -33,10 +33,10 @@ def getcaps():
 
 def listmailcapfiles():
     """Return a list of all mailcap files found on the system."""
-    # XXX Actually, this is Unix-specific
+    # This is mostly a Unix thing, but we use the OS path separator anyway
     if 'MAILCAPS' in os.environ:
-        str = os.environ['MAILCAPS']
-        mailcaps = str.split(':')
+        pathstr = os.environ['MAILCAPS']
+        mailcaps = pathstr.split(os.pathsep)
     else:
         if 'HOME' in os.environ:
             home = os.environ['HOME']

Misc/NEWS

@@ -268,6 +268,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #9923: The mailcap module now correctly uses the platform path
+  separator for the MAILCAP environment variable on non-POSIX platforms.
+
 - Issue #12835: Follow up to #6560 that unconditionally prevents use of the
   unencrypted sendmsg/recvmsg APIs on SSL wrapped sockets. Patch by David
   Watson.