--- Lib/subprocess.py.orig
+++ Lib/subprocess.py
@@ -820,37 +820,6 @@ def __init__(self, args, bufsize=-1, executable=None,
                                   'and universal_newlines are supplied but '
                                   'different. Pass one or the other.')
 
-        # Input and output objects. The general principle is like
-        # this:
-        #
-        # Parent                   Child
-        # ------                   -----
-        # p2cwrite   ---stdin--->  p2cread
-        # c2pread    <--stdout---  c2pwrite
-        # errread    <--stderr---  errwrite
-        #
-        # On POSIX, the child objects are file descriptors.  On
-        # Windows, these are Windows file handles.  The parent objects
-        # are file descriptors on both platforms.  The parent objects
-        # are -1 when not using PIPEs. The child objects are -1
-        # when not redirecting.
-
-        (p2cread, p2cwrite,
-         c2pread, c2pwrite,
-         errread, errwrite) = self._get_handles(stdin, stdout, stderr)
-
-        # We wrap OS handles *before* launching the child, otherwise a
-        # quickly terminating child could make our fds unwrappable
-        # (see #8458).
-
-        if _mswindows:
-            if p2cwrite != -1:
-                p2cwrite = msvcrt.open_osfhandle(p2cwrite.Detach(), 0)
-            if c2pread != -1:
-                c2pread = msvcrt.open_osfhandle(c2pread.Detach(), 0)
-            if errread != -1:
-                errread = msvcrt.open_osfhandle(errread.Detach(), 0)
-
         self.text_mode = encoding or errors or text or universal_newlines
 
         # How long to resume waiting on a child after the first ^C.
@@ -941,6 +910,39 @@ def __init__(self, args, bufsize=-1, executable=None,
             if uid < 0:
                 raise ValueError(f"User ID cannot be negative, got {uid}")
 
+        # Input and output objects. The general principle is like
+        # this:
+        #
+        # Parent                   Child
+        # ------                   -----
+        # p2cwrite   ---stdin--->  p2cread
+        # c2pread    <--stdout---  c2pwrite
+        # errread    <--stderr---  errwrite
+        #
+        # On POSIX, the child objects are file descriptors.  On
+        # Windows, these are Windows file handles.  The parent objects
+        # are file descriptors on both platforms.  The parent objects
+        # are -1 when not using PIPEs. The child objects are -1
+        # when not redirecting.
+
+        (p2cread, p2cwrite,
+         c2pread, c2pwrite,
+         errread, errwrite) = self._get_handles(stdin, stdout, stderr)
+
+        # We wrap OS handles *before* launching the child, otherwise a
+        # quickly terminating child could make our fds unwrappable
+        # (see #8458).
+
+        if _mswindows:
+            if p2cwrite != -1:
+                p2cwrite = msvcrt.open_osfhandle(p2cwrite.Detach(), 0)
+            if c2pread != -1:
+                c2pread = msvcrt.open_osfhandle(c2pread.Detach(), 0)
+            if errread != -1:
+                errread = msvcrt.open_osfhandle(errread.Detach(), 0)
+
+        # WARNING: Raising exceptions here may cause file descriptor leakage!
+
         try:
             if p2cwrite != -1:
                 self.stdin = io.open(p2cwrite, 'wb', bufsize)