Issue #25488: Stpp idle.py from adding a entry when it is a duplicate.
Also, make idlelib.idle.main() work after import idlelib.idle.
diff --git a/Lib/idlelib/idle.py b/Lib/idlelib/idle.py
index a249557..141534d 100644
--- a/Lib/idlelib/idle.py
+++ b/Lib/idlelib/idle.py
@@ -1,11 +1,13 @@
import os.path
import sys
-# If we are working on a development version of IDLE, we need to prepend the
-# parent of this idlelib dir to sys.path. Otherwise, importing idlelib gets
-# the version installed with the Python used to call this module:
+# Enable running IDLE with idlelib in a non-standard location.
+# This was once used to run development versions of IDLE.
+# Because PEP 434 declared idle.py a public interface,
+# removal should require deprecation.
idlelib_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-sys.path.insert(0, idlelib_dir)
+if idlelib_dir not in sys.path:
+ sys.path.insert(0, idlelib_dir)
-import idlelib.PyShell
-idlelib.PyShell.main()
+from idlelib.PyShell import main # This is subject to change
+main()