[RFC] Fix #471 Parallel

[Shougo]

It is on WIP.

Note: profile and debug feature is not supported.

You can test the feature!

[Shougo]

The current status is:

The refactoring before threading is done.
The next is threading support.

[Shougo]

Note: profile and debug feature is not supported.

I will fix the problem later.

[Shougo]

@roxma I have added the threading feature.
But it does not work...
Can you test the plugin?

[Shougo]

attach vim in another thread seems does not work.
It works on nvim-completion-manager though.

[Shougo]

I have updated it.
It still WIP though.

[Shougo]

I have implemented the feature.
But it will be crashed by Out of memory.
Why?

[Shougo]

The more testers and the code reviewers are needed.

[Mte90]

I can help to test on vim in case :-) What is the way to get that branch with vundle?

[deathmaz]

any configuration needed to make it to work? i'm on linux and it didn't work when i switched the branch

[Shougo]

I can help to test on vim in case :-) What is the way to get that branch with vundle?

Vundle does not support branch swich.
You can switch the branch manually.

any configuration needed to make it to work? i'm on linux and it didn't work when i switched the branch

No additional configuration is needed.
Note: It is very experimental. It is slow. You must wait few second.

[deathmaz]

@Shougo yes, it works after i wait for a few seconds, do you need to test some specific things?

[Shougo]

@Shougo yes, it works after i wait for a few seconds, do you need to test some specific things?

Nothing. It works. But it is very experimental.

I'm waiting for neovim/pynvim#294.

[Shougo]

I will change the implementation using msgpack instead of Vim variables.

[Shougo]

I have completed the development.
More testers are needed.
Especially Windows environment.

@blueyed Profile and debug feature tests are needed.

[Shougo]

I will add the error check later.
I think python exe(get(g:, 'python3_host_prog', 'python3')) is not in $PATH.

[jsfaint]

@Shougo Sorry, I checked the vimrc, the g:python3_host_prog is only set for vim

if !has('nvim')
  let g:python3_host_prog = 'C:/Users/jia.sui/AppData/Local/Programs/Python/Python36/python.exe'
endif

After set the g:python3_host_prog and then try to use the completion.
There are 4 python processes eat up my CPU, and there is no completion window showed up

[Shougo]

I don't know why it does not work.
You can research the problem.

Note: You have seen the help wanted label.
deoplete is Python3 based. It is easy to contribute.

[balta2ar]

You're using msgpack here. What's the reasoning for this choice? Could it be JSON or Pickle instead? I'm not questioning the choice, it's just good for my own knowledge to know which one to pick in which situation.

[Shougo]

You're using msgpack here. What's the reasoning for this choice? Could it be JSON or Pickle instead? I'm not questioning the choice, it's just good for my own knowledge to know which one to pick in which situation.

It is good question.
I have choosed the library because:

• neovim uses it(No additional dependency).
• It supports stream decode. It is useful for standard input/output communication.
• The decode/encode performance is good than json.

[Shougo]

Merged.

[balta2ar]

Unfortunately, it broke my deoplete plugin...

[deoplete] Traceback (most recent call last):
[deoplete]   File "/home/user/.vim/plugged/deoplete.nvim/rplugin/python3/deoplete/deoplete.py", line 63, in completion_begin
[deoplete]     is_async, position, candidates = self.merge_results(context)
[deoplete]   File "/home/user/.vim/plugged/deoplete.nvim/rplugin/python3/deoplete/deoplete.py", line 110, in merge_results
[deoplete]     result = parent.merge_results(context)
[deoplete]   File "/home/user/.vim/plugged/deoplete.nvim/rplugin/python3/deoplete/parent.py", line 51, in merge_results
[deoplete]     get = self._get(queue_id)
[deoplete]   File "/home/user/.vim/plugged/deoplete.nvim/rplugin/python3/deoplete/parent.py", line 91, in _get
[deoplete]     return [x for x in self._proc.communicate(15)
[deoplete]   File "/home/user/.vim/plugged/deoplete.nvim/rplugin/python3/deoplete/parent.py", line 92, in <listcomp>
[deoplete]     if x['queue_id'] == queue_id]
[deoplete] TypeError: 'int' object is not subscriptable
[deoplete] Error while gathering completions.  Use :messages for error details.

[Shougo]

@balta2ar I cannot reproduce the problem.
Please create the new issue. We have not ESP skills.
Otherwise, I will ignore your issue.

Unfortunately, it broke my deoplete plugin...

What is the plugin?

[balta2ar]

It looks like I found the problem in my code: I had several prints here and there in my plugin, so their output of course was unexpected to the Parent class. I removed prints, and the errors were gone. I know it's not the issue of the plugin, but is there anything that can be done to help find such problems easier? How about printing a friendly message saying "Unexpected output from child process. Are you printing something to stdout there?". That's just an idea though.

But there is still a problem. My plugin relies on the is_async flag logic: I expect that deoplete will keep calling my gather_candidates method until I set context["is_async"] to False. When I process data in the background, I keep setting is_async to True. But it appears that deoplete does not call me again when my results are ready. Could you please check this behavior?

[Shougo]

How about printing a friendly message saying "Unexpected output from child process. Are you printing something to stdout there?". That's just an idea though.

If you can implement the feature, should be.
The PR is wellcome.

But it appears that deoplete does not call me again when my results are ready. Could you please check this behavior?

Hm. I will check the behavior later.
Please create the new issue for it.

[bfredl]

To support using print() in children could use stdout redirection (in the child) like the script host: https://github.com/neovim/python-client/blob/320cb7d92c2bfaabe10bd278efd99361ebabc2bf/neovim/plugin/script_host.py#L64

[bfredl]

Or maybe just sys.stdout = sys.stderr, and then handle stderr in the parent...

[Shougo]

OK. I will test that.

[Shougo]

diff --git a/rplugin/python3/deoplete/child.py b/rplugin/python3/deoplete/child.py
index 1e14e09..464e1fd 100644
--- a/rplugin/python3/deoplete/child.py
+++ b/rplugin/python3/deoplete/child.py
@@ -79,10 +79,13 @@ class Child(logger.LoggingMixin):
                     self._on_event(args[0])
                 elif name == 'merge_results':
                     self._write(self._merge_results(args[0], queue_id))
+                self.debug('main_loop: end')
 
     def _write(self, expr):
-        sys.stdout.buffer.write(self._packer.pack(expr))
-        sys.stdout.flush()
+        # sys.stdout.buffer.write(self._packer.pack(expr))
+        # sys.stdout.flush()
+        sys.stderr.buffer.write(self._packer.pack(expr))
+        sys.stderr.flush()
 
     def _enable_logging(self):
         logging = self._vim.vars['deoplete#_logging']
@@ -141,6 +144,7 @@ class Child(logger.LoggingMixin):
                 self.debug('Loaded Filter: %s (%s)', f.name, path)
 
     def _merge_results(self, context, queue_id):
+        self.debug('merged_results: begin')
         results = self._gather_results(context)
 
         merged_results = []
@@ -162,6 +166,7 @@ class Child(logger.LoggingMixin):
 
         is_async = len([x for x in results if x['context']['is_async']]) > 0
 
+        self.debug('merged_results: end')
         return {
             'queue_id': queue_id,
             'is_async': is_async,

diff --git a/rplugin/python3/deoplete/dp_main.py b/rplugin/python3/deoplete/dp_main.py
index 04e0448..dff1e84 100644
--- a/rplugin/python3/deoplete/dp_main.py
+++ b/rplugin/python3/deoplete/dp_main.py
@@ -5,6 +5,7 @@
 # ============================================================================
 
 import sys
+import io
 
 from neovim import attach
 
@@ -28,10 +29,21 @@ def attach_vim(serveraddr):
     return vim
 
 
+class RedirectStream(io.IOBase):
+    def __init__(self, redirect_handler):
+        self.redirect_handler = redirect_handler
+
+    def write(self, data):
+        self.redirect_handler(data)
+
+    def writelines(self, seq):
+        self.redirect_handler('\n'.join(seq))
+
 def main(serveraddr):
     vim = attach_vim(serveraddr)
     from deoplete.child import Child
     from deoplete.util import error_tb
+    sys.stdout = RedirectStream(lambda data: vim.out_write(data))
     try:
         child = Child(vim)
         child.main()
diff --git a/rplugin/python3/deoplete/process.py b/rplugin/python3/deoplete/process.py
index d1ac7b3..e81ca35 100644
--- a/rplugin/python3/deoplete/process.py
+++ b/rplugin/python3/deoplete/process.py
@@ -52,7 +52,11 @@ class Process(object):
 
     def enqueue_output(self):
         while self._proc:
-            b = self._proc.stdout.read(1)
+            # b = self._proc.stdout.raw.read(102400)
+            b = self._proc.stderr.raw.read(102400)
+            if b == b'':
+                return
+
             self._unpacker.feed(b)
             for child_out in self._unpacker:
                 self._queue_out.put(child_out)

Hm. It may be better.

[Shougo]

@bfredl I cannot use stderr because of wsdjeg/SpaceVim#1397

[Shougo]

@balta2ar I have fixed stdout problem completely.

[bfredl]

Why are you sending the msgpack over stderr? That will indeed cause all sorts of trouble... Instead, use the original stdout stream:

self.stdout = sys.stdout # use it for msgpack
sys.stdout = RedirectStream(...) # gets print() out of the way

[Shougo]

Yes. I have fixed it in the latest version.