2 files changed, 10 insertions, 0 deletions
diff --git a/Misc/NEWS b/Misc/NEWS
index 41ba1a8..35ffbfd 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -734,6 +734,12 @@ IDLE
 - Issue #17532: Always include Options menu for IDLE on OS X.
   Patch by Guilherme Simões.
 
+Windows
+-------
+
+- Issue #18569: The installer now adds .py to the PATHEXT variable when extensions
+  are registered. Patch by Paul Moore.
+
 Build
 -----
 
diff --git a/Tools/msi/msi.py b/Tools/msi/msi.py
index 8d088ff..3e3cef1 100644
--- a/Tools/msi/msi.py
+++ b/Tools/msi/msi.py
@@ -1270,6 +1270,10 @@ def add_registry(db):
               "{60254CA5-953B-11CF-8C96-00AA00B8708C}", "REGISTRY.def"),
             ])
 
+    # PATHEXT
+    add_data(db, "Environment",
+             [("PathExtAddition", "=-*PathExt", "[~];.PY", "REGISTRY.def")])
+
     # Registry keys
     prefix = r"Software\%sPython\PythonCore\%s" % (testprefix, short_version)
     add_data(db, "Registry",