notes and better error message

ubelt/util_deprecate.py

@@ -164,6 +164,8 @@ def schedule_deprecation(modname=None, name='?', type='?', migration='',
         module = sys.modules[modname]
         current = Version(module.__version__)
     else:
+        # TODO: use the inspect module to get the function / module this was
+        # called from and fill in unspecified values.
         current = 'unknown'
 
     def _handle_when(when, default):
@@ -190,6 +192,7 @@ def _handle_when(when, default):
     remove_now, remove_str = _handle_when(remove, default=False)
     error_now, error_str = _handle_when(error, default=False)
 
+    # TODO: make the message more customizable.
     msg = (
         'The "{name}" {type} was deprecated{deprecate_str}, will cause '
         'an error{error_str} and will be removed{remove_str}. The current '

ubelt/util_import.py

@@ -625,9 +625,10 @@ def _custom_import_modpath(modpath, index=-1):
         with PythonPathContext(dpath, index=index):
             module = import_module_from_name(modname)
     except Exception as ex:  # nocover
-        msg_parts = [
-            'ERROR: Failed to import modname={} with modpath={}'.format(
-                modname, modpath)
+        msg_parts = [(
+            'ERROR: Failed to import modname={} with modpath={} and '
+            'sys.path modified with {} at index={}').format(
+                modname, modpath, repr(dpath), index)
         ]
         msg_parts.append('Caused by: {}'.format(repr(ex)))
         raise RuntimeError('\n'.join(msg_parts))