meld/melddoc.py: Fix windows external open (#354)

When in a Meld folder comparison in Windows, a file or subfolder can be
opened externally with default windows application (e.g. explorer for
folders, previously selected application for files, or the windows
file open option popup for unspecified types).

Right-mouse button click and "Open externally" should produce this
behaviour, however currently folders with spaces in the path produce
unexpected behaviour such as command line windows opening.

Changing the relevant system call from subprocess.Popen() to the
windows-specific os.startfile() fixes this behaviour and handles paths
with spaces in them in the expected way.

https://gitlab.gnome.org/GNOME/meld/-/issues/354

Author: adam0antium

meld/melddoc.py

@@ -16,6 +16,7 @@
 
 import enum
 import logging
+import os
 import pipes
 import shlex
 import string
@@ -127,7 +128,7 @@ def os_open(path: str, uri: str):
             if not path:
                 return
             if sys.platform == "win32":
-                subprocess.Popen(["start", path], shell=True)
+                os.startfile(path)
             elif sys.platform == "darwin":
                 subprocess.Popen(["open", path])
             else: