jobstop(): close channel before process_stop() #10522

fix #9799
regression of #7081
Helped-by: Björn Linse <bjorn.linse@gmail.com>

Problem: :UpdateRemotePlugins (which calls rpcstop()) sometimes crashes:

    remote/host: python3 host registered plugins []
    nvim: ../src/nvim/event/wstream.c:78:
      _Bool wstream_write(Stream *, WBuffer *): Assertion `!stream->closed' failed.
    Aborted (core dumped)

  Order of events (channel 163, see logs below):

    1. Channel's in-stream (0x2ba86c0) is **closed** by `f_rpcstop`..`process_stop`.
    2. `receive_msgpack` parses the channel out-stream (0x2ba8860)
    3. Invokes "nvim_command_output" API method.
    4. Writes result to the **closed** in-stream  => **abort**

  - af993da4351d (`receive_msgpack`) tried to hack around same/similar issue.
  - Hack was removed in 5215e3205a07.

Solution: in jobstop(), close the channel before process_stop().

Log:

    DEBUG 2019-07-16T20:54:12.191 25159 stream_close:96: closing Stream: 0x2b01a90
    DEBUG 2019-07-16T20:54:12.210 25159 process_spawn:124: new: pid=28407 argv=[/usr/bin/python3]
    DEBUG 2019-07-16T20:54:12.210 25159 rpc_start:72: rpc ch 163 in-stream=0x2ba86c0 out-stream=0x2ba8860
    INFO  2019-07-16T20:54:12.210 25159 channel_create_event:199: new channel 163 (function <SNR>61_on_exit[4]..<SNR>60_job_exit_cb[101]..<SNR>60_decrement_job_count[8]..remote#host#UpdateRemotePlugins[6]..<SNR>31_RegistrationCommands[15]..remote#host#Require[10]..provider#pythonx#Require[13]..provider#Poll:3) : {"id": 163, "client": {}, "mode": "rpc", "stream": "job"}
    DEBUG 2019-07-16T20:54:12.211 25159 log_server_msg:729: RPC ->ch 163: [request]  [0, 1, "poll", []]
    DEBUG 2019-07-16T20:54:12.355 25159 receive_msgpack:227: ch 163: parsing 21 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.355 25159 log_client_msg:766: RPC <-ch 163: [request]  [0, 1, "vim_get_api_info", []]
    DEBUG 2019-07-16T20:54:12.355 25159 RPC: <-ch 163: invoke nvim_get_api_info
    DEBUG 2019-07-16T20:54:12.357 25159 log_server_msg:729: RPC ->ch 163: [response] [1, 1, nil, [163, {"version"=>{"major"=>0, "minor"=>4, }, ...
    DEBUG 2019-07-16T20:54:12.377 25159 receive_msgpack:227: ch 163: parsing 85 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.377 25159 log_client_msg:766: RPC <-ch 163: [request]  [0, 2, "nvim_eval", ["((&number||&relativenumber) ? &numberwidth : 0) + &foldcolumn"]]
    DEBUG 2019-07-16T20:54:12.377 25159 handle_request:359: RPC: scheduled nvim_eval
    DEBUG 2019-07-16T20:54:12.377 25159 log_client_msg:766: RPC <-ch 163: [response] [1, 1, nil, "ok"]
    DEBUG 2019-07-16T20:54:12.378 25159 log_server_msg:729: RPC ->ch 163: [request]  [0, 2, "specs", ["/home/vagrant/.config/nvim/rplugin/python3/__pycache__"]]
    DEBUG 2019-07-16T20:54:12.378 25159 RPC: <-ch 163: invoke nvim_eval
    DEBUG 2019-07-16T20:54:12.379 25159 log_server_msg:729: RPC ->ch 163: [response] [1, 2, nil, 0]
    DEBUG 2019-07-16T20:54:12.379 25159 receive_msgpack:227: ch 163: parsing 5 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.379 25159 log_client_msg:766: RPC <-ch 163: [response] [1, 2, nil, 0]
    DEBUG 2019-07-16T20:54:12.380 25159 log_server_msg:729: RPC ->ch 163: [request]  [0, 3, "specs", ["/home/vagrant/.config/nvim/rplugin/python3/foo.py"]]
    DEBUG 2019-07-16T20:54:12.380 25159 receive_msgpack:227: ch 163: parsing 79 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.380 25159 log_client_msg:766: RPC <-ch 163: [request]  [0, 3, "nvim_command", ["redir =>a |exe "sil sign place buffer=".bufnr('')|redir end"]]
    DEBUG 2019-07-16T20:54:12.381 25159 handle_request:359: RPC: scheduled nvim_command
    DEBUG 2019-07-16T20:54:12.381 25159 RPC: <-ch 163: invoke nvim_command
    DEBUG 2019-07-16T20:54:12.381 25159 log_server_msg:729: RPC ->ch 163: [response] [1, 3, nil, nil]
    DEBUG 2019-07-16T20:54:12.381 25159 receive_msgpack:227: ch 163: parsing 5 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.381 25159 log_client_msg:766: RPC <-ch 163: [response] [1, 3, nil, 0]
    DEBUG 2019-07-16T20:54:12.382 25159 stream_close:95: trace:
      log_callstack at /home/vagrant/neovim/build/../src/nvim/log.c:256
      stream_close at /home/vagrant/neovim/build/../src/nvim/event/stream.c:95
      stream_may_close at /home/vagrant/neovim/build/../src/nvim/event/stream.c:111
      process_stop at /home/vagrant/neovim/build/../src/nvim/event/process.c:230
      f_jobstop at /home/vagrant/neovim/build/../src/nvim/eval.c:12231
      f_rpcstop at /home/vagrant/neovim/build/../src/nvim/eval.c:14533
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6564
      get_func_tv at /home/vagrant/neovim/build/../src/nvim/eval.c:6304
      ex_call at /home/vagrant/neovim/build/../src/nvim/eval.c:2903
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2249
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      call_user_func at /home/vagrant/neovim/build/../src/nvim/eval.c:22666
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6550
      get_func_tv at /home/vagrant/neovim/build/../src/nvim/eval.c:6304
      eval7 at /home/vagrant/neovim/build/../src/nvim/eval.c:4407
      eval6 at /home/vagrant/neovim/build/../src/nvim/eval.c:4104
      eval5 at /home/vagrant/neovim/build/../src/nvim/eval.c:3985
      eval4 at /home/vagrant/neovim/build/../src/nvim/eval.c:3688
      eval3 at /home/vagrant/neovim/build/../src/nvim/eval.c:3606
      eval2 at /home/vagrant/neovim/build/../src/nvim/eval.c:3537
      eval1 at /home/vagrant/neovim/build/../src/nvim/eval.c:3464
      eval0 at /home/vagrant/neovim/build/../src/nvim/eval.c:3424
      ex_let_const at /home/vagrant/neovim/build/../src/nvim/eval.c:1604
      ex_let at /home/vagrant/neovim/build/../src/nvim/eval.c:1546
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2249
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      call_user_func at /home/vagrant/neovim/build/../src/nvim/eval.c:22666
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6550
      get_func_tv at /home/vagrant/neovim/build/../src/nvim/eval.c:6304
      ex_call at /home/vagrant/neovim/build/../src/nvim/eval.c:2903
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2249
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      do_ucmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:5803
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2243
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      call_user_func at /home/vagrant/neovim/build/../src/nvim/eval.c:22666
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6550
      get_func_tv at /home/vagrant/neovim/build/../src/nvim/eval.c:6304
      ex_call at /home/vagrant/neovim/build/../src/nvim/eval.c:2903
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2249
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      call_user_func at /home/vagrant/neovim/build/../src/nvim/eval.c:22666
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6550
      get_func_tv at /home/vagrant/neovim/build/../src/nvim/eval.c:6304
      ex_call at /home/vagrant/neovim/build/../src/nvim/eval.c:2903
      do_one_cmd at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:2249
      do_cmdline at /home/vagrant/neovim/build/../src/nvim/ex_docmd.c:593
      call_user_func at /home/vagrant/neovim/build/../src/nvim/eval.c:22666
      call_func at /home/vagrant/neovim/build/../src/nvim/eval.c:6550
      callback_call at /home/vagrant/neovim/build/../src/nvim/eval.c:17917
      channel_callback_call at /home/vagrant/neovim/build/../src/nvim/channel.c:675
      on_channel_event at /home/vagrant/neovim/build/../src/nvim/channel.c:581
      multiqueue_process_events at /home/vagrant/neovim/build/../src/nvim/event/multiqueue.c:147
      nv_event at /home/vagrant/neovim/build/../src/nvim/normal.c:7987
      normal_execute at /home/vagrant/neovim/build/../src/nvim/normal.c:1133
      state_enter at /home/vagrant/neovim/build/../src/nvim/state.c:73
      normal_enter at /home/vagrant/neovim/build/../src/nvim/normal.c:462
      main at /home/vagrant/neovim/build/../src/nvim/main.c:570
      ?? ??:0
      _start at ??:?
    DEBUG 2019-07-16T20:54:12.417 25159 stream_close:96: closing Stream: 0x2ba86c0
    INFO  2019-07-16T20:54:12.417 25159 os_proc_tree_kill:96: sending SIGTERM to process group: -28407
    DEBUG 2019-07-16T20:54:12.417 25159 receive_msgpack:227: ch 163: parsing 31 bytes from msgpack Stream: 0x2ba8860
    DEBUG 2019-07-16T20:54:12.417 25159 log_client_msg:766: RPC <-ch 163: [request]  [0, 4, "nvim_command_output", ["echo a"]]
    DEBUG 2019-07-16T20:54:12.417 25159 handle_request:359: RPC: scheduled nvim_command_output
    DEBUG 2019-07-16T20:54:12.424 25159 RPC: <-ch 163: invoke nvim_command_output
    DEBUG 2019-07-16T20:54:12.424 25159 log_server_msg:729: RPC ->ch 163: [response] [1, 4, [0, "Vim(echo):E121: Undefined variable: a"], nil]
    ERROR 2019-07-16T20:54:12.424 25159 wstream_write:78: xxx stream=0x2ba86c0
    DEBUG 2019-07-16T20:54:12.425 25159 wstream_write:79: trace:
      log_callstack at /home/vagrant/neovim/build/../src/nvim/log.c:256
      wstream_write at /home/vagrant/neovim/build/../src/nvim/event/wstream.c:82
      channel_write at /home/vagrant/neovim/build/../src/nvim/msgpack_rpc/channel.c:407
      request_event at /home/vagrant/neovim/build/../src/nvim/msgpack_rpc/channel.c:383
      multiqueue_process_events at /home/vagrant/neovim/build/../src/nvim/event/multiqueue.c:147
      nv_event at /home/vagrant/neovim/build/../src/nvim/normal.c:7987
      normal_execute at /home/vagrant/neovim/build/../src/nvim/normal.c:1133
      state_enter at /home/vagrant/neovim/build/../src/nvim/state.c:73
      normal_enter at /home/vagrant/neovim/build/../src/nvim/normal.c:462
      main at /home/vagrant/neovim/build/../src/nvim/main.c:570
      ?? ??:0
      _start at ??:?

5 files changed, 16 insertions, 7 deletions

diff --git a/runtime/autoload/remote/host.vim b/runtime/autoload/remote/host.vim
index 6266b312bd..1cf328e08d 100644
--- a/runtime/autoload/remote/host.vim
+++ b/runtime/autoload/remote/host.vim
@@ -147,7 +147,7 @@ function! s:RegistrationCommands(host) abort
         \ a:host, string(map(registered, "fnamemodify(v:val, ':t')")))
 
   " Delete the temporary host clone
-  call rpcstop(s:hosts[host_id].channel)
+  call jobstop(s:hosts[host_id].channel)
   call remove(s:hosts, host_id)
   call remove(s:plugins_for_host, host_id)
   return lines
diff --git a/runtime/doc/deprecated.txt b/runtime/doc/deprecated.txt
index c58215dce6..27e60be368 100644
--- a/runtime/doc/deprecated.txt
+++ b/runtime/doc/deprecated.txt
@@ -44,6 +44,11 @@ Functions ~
 *jobclose()*		Obsolete name for |chanclose()|
 *jobsend()*		Obsolete name for |chansend()|
 *last_buffer_nr()*	Obsolete name for bufnr("$").
+*rpcstop()*		Deprecated. Instead use |jobstop()| to stop any job,
+			or chanclose(id, "rpc") to close RPC communication
+			without stopping the job. Use chanclose(id) to close
+			any socket.
+
 
 Modifiers ~
 *cpo-<*
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 091add5db3..06af04bf63 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -6708,11 +6708,6 @@ rpcstart({prog}[, {argv}])					*rpcstart()*
 <		with >
 			:let id = jobstart(['prog', 'arg1', 'arg2'], {'rpc': v:true})
 
-rpcstop({channel})						*rpcstop()*
-		Deprecated. Instead use |jobstop()| to stop any job, and
-		chanclose(id, "rpc") to close RPC communication without
-		stopping the job. Use chanclose(id) to close any socket.
-
 screenattr({row}, {col})					*screenattr()*
 		Like |screenchar()|, but return the attribute.  This is a rather
 		arbitrary number that can only be used to compare to the
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 1a690fdf8f..7a8402a6bb 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -12227,8 +12227,16 @@ static void f_jobstop(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     return;
   }
 
+  const char *error = NULL;
+  if (data->is_rpc) {
+    // Ignore return code, but show error later.
+    (void)channel_close(data->id, kChannelPartRpc, &error);
+  }
   process_stop((Process *)&data->stream.proc);
   rettv->vval.v_number = 1;
+  if (error) {
+    EMSG(error);
+  }
 }
 
 // "jobwait(ids[, timeout])" function
diff --git a/src/nvim/generators/gen_api_dispatch.lua b/src/nvim/generators/gen_api_dispatch.lua
index 95dcbc732e..76dcf849d1 100644
--- a/src/nvim/generators/gen_api_dispatch.lua
+++ b/src/nvim/generators/gen_api_dispatch.lua
@@ -198,7 +198,8 @@ for i = 1, #functions do
     output:write('Object handle_'..fn.name..'(uint64_t channel_id, Array args, Error *error)')
     output:write('\n{')
     output:write('\n#if MIN_LOG_LEVEL <= DEBUG_LOG_LEVEL')
-    output:write('\n  logmsg(DEBUG_LOG_LEVEL, "RPC: ", NULL, -1, true, "invoke '..fn.name..'");')
+    output:write('\n  logmsg(DEBUG_LOG_LEVEL, "RPC: ", NULL, -1, true, "ch %" PRIu64 ": invoke '
+                 ..fn.name..'", channel_id);')
     output:write('\n#endif')
     output:write('\n  Object ret = NIL;')
     -- Declare/initialize variables that will hold converted arguments