Issue #16481: Merge

Lib/multiprocessing/forking.py

@@ -233,6 +233,7 @@ else:
                 self.returncode = None
                 self._handle = hp
                 self.sentinel = int(hp)
+                util.Finalize(self, _winapi.CloseHandle, (self.sentinel,))
 
                 # send information to child
                 Popen._tls.process_handle = int(hp)

Misc/NEWS

@@ -127,6 +127,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #16481: multiprocessing no longer leaks process handles on Windows.
+
 - Issue #12428: Add a pure Python implementation of functools.partial().
   Patch by Brian Thorne.