bpo-35516: platform.system_alias() don't replace Darwin (GH-11207)

Add a comment explaining why system_alias() doesn't alias Darwin to
macOS.

diff --git a/Lib/platform.py b/Lib/platform.py
index 9dd3f47075bf70fb0d553a1ebddec3067b34edb9..2ab68aed7861380a302ebde4970069a7bd45ca4d 100755 (executable)
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -514,6 +514,9 @@ def system_alias(system, release, version):
         # In case one of the other tricks
         system = 'Windows'
 
+    # bpo-35516: Don't replace Darwin with macOS since input release and
+    # version arguments can be different than the currently running version.
+
     return system, release, version
 
 ### Various internal helpers