hamster wheel: avoid "imp" module

"imp" was deprecated in python 3.7.

closes #351

Author: justinmk

pynvim/compat.py

@@ -2,18 +2,23 @@
 
 import sys
 import warnings
-from imp import find_module as original_find_module
+if sys.version_info >= (3, 4):
+    from importlib.machinery import PathFinder
+    original_find_module = PathFinder.find_spec
+else:
+    from imp import find_module as original_find_module
 
 
 IS_PYTHON3 = sys.version_info >= (3, 0)
+IS_PYTHON3_7 = sys.version_info >= (3, 7)
 
 
 if IS_PYTHON3:
     def find_module(fullname, path):
-        """Compatibility wrapper for imp.find_module.
+        """Compatibility wrapper for imp.find_module
+        (or find_spec in Python 3.7+).
 
-        Automatically decodes arguments of find_module, in Python3
-        they must be Unicode
+        Automatically decodes arguments (must be Unicode in Python3).
         """
         if isinstance(fullname, bytes):
             fullname = fullname.decode()

pynvim/plugin/script_host.py

@@ -1,12 +1,16 @@
 """Legacy python/python3-vim emulation."""
-import imp
+try:
+    import importlib
+except ImportError:
+    import imp
 import io
 import logging
 import os
 import sys
 
 from .decorators import plugin, rpc_export
 from ..api import Nvim, walk
+from ..compat import IS_PYTHON3, IS_PYTHON3_7, find_module
 from ..msgpack_rpc import ErrorResponse
 from ..util import format_exc_skip
 
@@ -16,8 +20,6 @@
 logger = logging.getLogger(__name__)
 debug, info, warn = (logger.debug, logger.info, logger.warn,)
 
-IS_PYTHON3 = sys.version_info >= (3, 0)
-
 if IS_PYTHON3:
     basestring = str
 
@@ -38,7 +40,10 @@ def __init__(self, nvim):
         """Initialize the legacy python-vim environment."""
         self.setup(nvim)
         # context where all code will run
-        self.module = imp.new_module('__main__')
+        if IS_PYTHON3_7:
+            self.module = importlib.util.module_from_spec('__main__')
+        else:
+            self.module = imp.new_module('__main__')
         nvim.script_context = self.module
         # it seems some plugins assume 'sys' is already imported, so do it now
         exec('import sys', self.module.__dict__)
@@ -205,7 +210,7 @@ def eval(self, expr):
         return walk(num_to_str, obj)
 
 
-# This was copied/adapted from nvim-python help
+# Copied/adapted from :help if_pyth.
 def path_hook(nvim):
     def _get_paths():
         if nvim._thread_invalid():
@@ -217,11 +222,11 @@ def _find_module(fullname, oldtail, path):
         if idx > 0:
             name = oldtail[:idx]
             tail = oldtail[idx + 1:]
-            fmr = imp.find_module(name, path)
-            module = imp.find_module(fullname[:-len(oldtail)] + name, *fmr)
+            fmr = find_module(name, path)
+            module = find_module(fullname[:-len(oldtail)] + name, *fmr)
             return _find_module(fullname, tail, module.__path__)
         else:
-            return imp.find_module(fullname, path)
+            return find_module(fullname, path)
 
     class VimModuleLoader(object):
         def __init__(self, module):
@@ -233,7 +238,10 @@ def load_module(self, fullname, path=None):
                 return sys.modules[fullname]
             except KeyError:
                 pass
-            return imp.load_module(fullname, *self.module)
+            if IS_PYTHON3_7:
+                return importlib.import_module(fullname, *self.module)
+            else:
+                return imp.load_module(fullname, *self.module)
 
     class VimPathFinder(object):
         @staticmethod