* Second attempt to fix lmod "module" for ipython ("fix2")

(dated: 2020-06-09).
  WIP: Prevent indefinite lengthening of sys.path but not complete
  fix yet.

  Sigs:
    # -rw------- 1 wpurwant users 1290 2020-06-09 19:28 lmod_python_fix2.py
    # e218a4ac73762e0380c4bbe2290906b1  lmod_python_fix2.py

lmod/ipython/startup/lmod_python_fix.py

@@ -9,8 +9,19 @@ from env_modules_python import module as lmod_module
 
 def module(command, *arguments):
     lmod_module(command, *arguments)
-    sys.path = os.environ.get('PYTHONPATH').split(':') + sys.path
+    # BAD: This will cause alteration of PYTHONPATH in a way that may not be desirable.
+    sys_path_orig = sys.path
+    PYTHONPATH = os.environ.get('PYTHONPATH')
+    sys_path_new = PYTHONPATH.split(':') if PYTHONPATH is not None else []
+    for p in sys_path_orig:
+        if p not in sys_path_new:
+            sys_path_new.append(p)
+    print(sys_path_new)
+    sys.path = sys_path_new
+
     manual_ld_library_dir = os.environ.get('LMOD_MANUAL_LD_LIBRARY_PATH')
+    if manual_ld_library_dir is None:
+        return
 
     for search_path in os.getenv('LD_LIBRARY_PATH').split(':')[::-1]:
         if not os.path.isdir(search_path):