rplugin: conditionally enable nested notifications

README.md

@@ -59,9 +59,9 @@ below.
   process), and `vim.async_call` can be used to send results back to nvim.
 
 * Some methods accept an extra keyword-only argument `async`: `vim.eval`,
-  `vim.command` as well as the `vim.funcs` wrappers. The python host will not
-  wait for nvim to complete the request, which also means that the return value
-  is unavailable.
+  `vim.command` as well as the `vim.funcs` wrappers. When `async=True` is
+  passed, the python host will not wait for nvim to complete the request, which
+  also means that the return value is unavailable.
 
 #### Remote (new-style) plugins
 
@@ -96,6 +96,14 @@ If `sync=True` is supplied nvim will wait for the handler to finish (this is
 required for function return values), but by default handlers are executed
 asynchronously.
 
+Normally async handlers (`sync=False`, the default) are blocked while a
+synchronous handler is running. This ensures that async handlers can call
+requests without nvim confusing these requests with requests from a synchronous
+handler. To execute an asynchronous handler even when other handlers are
+running, add `allow_nested=True` to the decorator. The handler must then not
+make synchronous nvim requests, but it can make asynchronous requests, i e
+passing `async=True`.
+
 You need to run `:UpdateRemotePlugins` in nvim for changes in the specifications
 to have effect. For details see `:help remote-plugin` in nvim.
 

neovim/__init__.py

@@ -126,11 +126,11 @@ def setup_logging(name):
         logging.root.addHandler(handler)
         level = logging.INFO
         if 'NVIM_PYTHON_LOG_LEVEL' in os.environ:
-            l = getattr(logging,
-                        os.environ['NVIM_PYTHON_LOG_LEVEL'].strip(),
-                        level)
-            if isinstance(l, int):
-                level = l
+            lvl = getattr(logging,
+                          os.environ['NVIM_PYTHON_LOG_LEVEL'].strip(),
+                          level)
+            if isinstance(lvl, int):
+                level = lvl
         logger.setLevel(level)
 
 

neovim/api/nvim.py

@@ -298,9 +298,9 @@ def replace_termcodes(self, string, from_part=False, do_lt=True,
         return self.request('vim_replace_termcodes', string,
                             from_part, do_lt, special)
 
-    def out_write(self, msg):
+    def out_write(self, msg, **kwargs):
         """Print `msg` as a normal message."""
-        return self.request('nvim_out_write', msg)
+        return self.request('nvim_out_write', msg, **kwargs)
 
     def err_write(self, msg, **kwargs):
         """Print `msg` as an error message."""

neovim/plugin/decorators.py

@@ -43,7 +43,7 @@ def dec(f):
 
 
 def command(name, nargs=0, complete=None, range=None, count=None, bang=False,
-            register=False, sync=False, eval=None):
+            register=False, sync=False, allow_nested=False, eval=None):
     """Tag a function or plugin method as a Nvim command handler."""
     def dec(f):
         f._nvim_rpc_method_name = 'command:{}'.format(name)
@@ -73,17 +73,22 @@ def dec(f):
         if eval:
             opts['eval'] = eval
 
+        if not sync and allow_nested:
+            rpc_sync = "urgent"
+        else:
+            rpc_sync = sync
+
         f._nvim_rpc_spec = {
             'type': 'command',
             'name': name,
-            'sync': sync,
+            'sync': rpc_sync,
             'opts': opts
         }
         return f
     return dec
 
 
-def autocmd(name, pattern='*', sync=False, eval=None):
+def autocmd(name, pattern='*', sync=False, allow_nested=False, eval=None):
     """Tag a function or plugin method as a Nvim autocommand handler."""
     def dec(f):
         f._nvim_rpc_method_name = 'autocmd:{}:{}'.format(name, pattern)
@@ -98,17 +103,22 @@ def dec(f):
         if eval:
             opts['eval'] = eval
 
+        if not sync and allow_nested:
+            rpc_sync = "urgent"
+        else:
+            rpc_sync = sync
+
         f._nvim_rpc_spec = {
             'type': 'autocmd',
             'name': name,
-            'sync': sync,
+            'sync': rpc_sync,
             'opts': opts
         }
         return f
     return dec
 
 
-def function(name, range=False, sync=False, eval=None):
+def function(name, range=False, sync=False, allow_nested=False, eval=None):
     """Tag a function or plugin method as a Nvim function handler."""
     def dec(f):
         f._nvim_rpc_method_name = 'function:{}'.format(name)
@@ -124,10 +134,15 @@ def dec(f):
         if eval:
             opts['eval'] = eval
 
+        if not sync and allow_nested:
+            rpc_sync = "urgent"
+        else:
+            rpc_sync = sync
+
         f._nvim_rpc_spec = {
             'type': 'function',
             'name': name,
-            'sync': sync,
+            'sync': rpc_sync,
             'opts': opts
         }
         return f

neovim/plugin/host.py

@@ -1,12 +1,12 @@
 """Implements a Nvim host for python plugins."""
-import functools
 import imp
 import inspect
 import logging
 import os
 import os.path
 import re
 
+from functools import partial
 from traceback import format_exc
 
 from . import script_host
@@ -181,8 +181,8 @@ def predicate(o):
             if fn._nvim_prefix_plugin_path:
                 method = '{}:{}'.format(plugin_path, method)
 
-            fn_wrapped = functools.partial(self._wrap_function, fn,
-                                           sync, decode, nvim_bind, method)
+            fn_wrapped = partial(self._wrap_function, fn,
+                                 sync, decode, nvim_bind, method)
             self._copy_attributes(fn, fn_wrapped)
             # register in the rpc handler dict
             if sync: