Handle reloading of relative imports

Submodule reload is enforced by removing sys.modules reference. This
will make imports do the full uncached importing

mycroft/skills/skill_loader.py

@@ -14,7 +14,9 @@
 #
 """Periodically run by skill manager to load skills into memory."""
 import gc
+import importlib
 import os
+from os.path import dirname
 import sys
 from time import time
 
@@ -28,6 +30,28 @@
 SKILL_MAIN_MODULE = '__init__.py'
 
 
+def remove_submodule_refs(module_name):
+ """Ensure submodules are reloaded by removing the refs from sys.modules.
+
+ Python import system puts a reference for each module in the sys.modules
+ dictionary to bypass loading if a module is already in memory. To make
+ sure skills are completely reloaded these references are deleted.
+
+ Arguments:
+ module_name: name of skill module.
+ """
+ submodules = []
+ LOG.debug('Skill module'.format(module_name))
+ # Collect found submodules
+ for m in sys.modules:
+ if m.startswith(module_name + '.'):
+ submodules.append(m)
+ # Remove all references them to in sys.modules
+ for m in submodules:
+ LOG.debug('Removing sys.modules ref for {}'.format(m))
+ del(sys.modules[m])
+
+
 def load_skill_module(path, skill_id):
  """Load a skill module
 
@@ -39,19 +63,14 @@ def load_skill_module(path, skill_id):
  skill_id: skill_id used as skill identifier in the module list
  """
  module_name = skill_id.replace('.', '_')
- if sys.version_info >= (3, 5):
- import importlib.util
- spec = importlib.util.spec_from_file_location(module_name, path)
- mod = importlib.util.module_from_spec(spec)
- spec.loader.exec_module(mod)
- else:
- from importlib.machinery import SourceFileLoader
- mod = SourceFileLoader(module_name, path).load_module()
- if mod:
- sys.modules[module_name] = mod
- return mod
- else:
- return None
+
+ remove_submodule_refs(module_name)
+
+ spec = importlib.util.spec_from_file_location(module_name, path)
+ mod = importlib.util.module_from_spec(spec)
+ sys.modules[module_name] = mod
+ spec.loader.exec_module(mod)
+ return mod
 
 
 def _get_last_modified_time(path):