job: fix race between channel close and job exit

When channel's close_cb is called, the job this channel is assigned to
may still be alive and the result status of the job will be set to
FAILED (as no actual return code is available at that moment). This is
easily reproduced for me on a single CPU Linux VPS.

To fix this, check for job's status in exit_cb instead.

Signed-off-by: Pavel Borzenkov <pavel.borzenkov@gmail.com>

autoload/go/cmd.vim

@@ -446,7 +446,7 @@ function s:cmd_job(args) abort
 
   let start_options = {
         \ 'callback': callbacks.callback,
-        \ 'close_cb': callbacks.close_cb,
+        \ 'exit_cb': callbacks.exit_cb,
         \ }
 
   " modify GOPATH if needed

autoload/go/coverage.vim

@@ -288,7 +288,7 @@ function s:coverage_job(args)
 
   let start_options = {
         \ 'callback': callbacks.callback,
-        \ 'close_cb': callbacks.close_cb,
+        \ 'exit_cb': callbacks.exit_cb,
         \ }
 
   " modify GOPATH if needed

autoload/go/def.vim

@@ -303,7 +303,7 @@ function s:def_job(args) abort
 
   let start_options = {
         \ 'callback': callbacks.callback,
-        \ 'close_cb': callbacks.close_cb,
+        \ 'exit_cb': callbacks.exit_cb,
         \ }
 
   if &modified

autoload/go/guru.vim

@@ -155,21 +155,12 @@ function! s:async_guru(args) abort
     endif
   endif
 
-  function! s:close_cb(chan) closure
-    let messages = []
-    while ch_status(a:chan, {'part': 'out'}) == 'buffered'
-      let msg = ch_read(a:chan, {'part': 'out'})
-      call add(messages, msg)
-    endwhile
-
-    while ch_status(a:chan, {'part': 'err'}) == 'buffered'
-      let msg = ch_read(a:chan, {'part': 'err'})
-      call add(messages, msg)
-    endwhile
-
-    let l:job = ch_getjob(a:chan)
-    let l:info = job_info(l:job)
+  let messages = []
+  function! s:callback(chan, msg) closure
+    call add(messages, a:msg)
+  endfunction
 
+  function! s:exit_cb(job, exitval) closure
     let out = join(messages, "\n")
 
     let status = {
@@ -178,21 +169,22 @@ function! s:async_guru(args) abort
           \ 'state': "finished",
           \ }
 
-    if l:info.exitval
+    if a:exitval
       let status.state = "failed"
     endif
 
     call go#statusline#Update(status_dir, status)
 
     if has_key(a:args, 'custom_parse')
-      call a:args.custom_parse(l:info.exitval, out)
+      call a:args.custom_parse(a:exitval, out)
     else
-      call s:parse_guru_output(l:info.exitval, out, a:args.mode)
+      call s:parse_guru_output(a:exitval, out, a:args.mode)
     endif
   endfunction
 
   let start_options = {
-        \ 'close_cb': funcref("s:close_cb"),
+        \ 'callback': funcref("s:callback"),
+        \ 'exit_cb': funcref("s:exit_cb"),
         \ }
 
   if has_key(result, 'stdin_content')

autoload/go/job.vim

@@ -30,36 +30,25 @@ function go#job#Spawn(args)
     call add(self.messages, a:msg)
   endfunction
 
-  function cbs.close_cb(chan) dict
-    let l:job = ch_getjob(a:chan)
-    let l:status = job_status(l:job)
-
-    " the job might be in fail status, we assume by default it's failed.
-    " However if it's dead, we can use the real exitval
-    let exitval = 1
-    if l:status == "dead"
-      let l:info = job_info(l:job)
-      let exitval = l:info.exitval
-    endif
-
+  function cbs.exit_cb(job, exitval) dict
     if has_key(self, 'custom_cb')
-      call self.custom_cb(l:job, exitval, self.messages)
+      call self.custom_cb(a:job, a:exitval, self.messages)
     endif
 
     if has_key(self, 'error_info_cb')
-      call self.error_info_cb(l:job, exitval, self.messages)
+      call self.error_info_cb(a:job, a:exitval, self.messages)
     endif
 
     if get(g:, 'go_echo_command_info', 1)
-      if exitval == 0
+      if a:exitval == 0
         call go#util#EchoSuccess("SUCCESS")
       else
         call go#util#EchoError("FAILED")
       endif
     endif
 
     let l:listtype = go#list#Type("quickfix")
-    if exitval == 0
+    if a:exitval == 0
       call go#list#Clean(l:listtype)
       call go#list#Window(l:listtype)
       return
@@ -99,9 +88,9 @@ function go#job#Spawn(args)
     let cbs.callback = a:args.callback
   endif
 
-  " override close callback handler if user provided it
-  if has_key(a:args, 'close_cb')
-    let cbs.close_cb = a:args.close_cb
+  " override exit callback handler if user provided it
+  if has_key(a:args, 'exit_cb')
+    let cbs.exit_cb = a:args.exit_cb
   endif
 
   return cbs

autoload/go/lint.vim

@@ -252,23 +252,14 @@ function s:lint_job(args)
     copen
   endfunction
 
-  function! s:close_cb(chan) closure
-    let l:job = ch_getjob(a:chan)
-    let l:status = job_status(l:job)
-
-    let exitval = 1
-    if l:status == "dead"
-      let l:info = job_info(l:job)
-      let exitval = l:info.exitval
-    endif
-
+  function! s:exit_cb(job, exitval) closure
     let status = {
           \ 'desc': 'last status',
           \ 'type': "gometaliner",
           \ 'state': "finished",
           \ }
 
-    if exitval
+    if a:exitval
       let status.state = "failed"
     endif
 
@@ -297,7 +288,7 @@ function s:lint_job(args)
 
   let start_options = {
         \ 'callback': funcref("s:callback"),
-        \ 'close_cb': funcref("s:close_cb"),
+        \ 'exit_cb': funcref("s:exit_cb"),
         \ }
 
   call job_start(a:args.cmd, start_options)

autoload/go/rename.vim

@@ -71,28 +71,25 @@ function s:rename_job(args)
 
   let status_dir =  expand('%:p:h')
 
-  function! s:close_cb(chan) closure
-    let l:job = ch_getjob(a:chan)
-    let l:info = job_info(l:job)
-
+  function! s:exit_cb(job, exitval) closure
     let status = {
           \ 'desc': 'last status',
           \ 'type': "gorename",
           \ 'state': "finished",
           \ }
 
-    if l:info.exitval
+    if a:exitval
       let status.state = "failed"
     endif
 
     call go#statusline#Update(status_dir, status)
 
-    call s:parse_errors(l:info.exitval, a:args.bang, messages)
+    call s:parse_errors(a:exitval, a:args.bang, messages)
   endfunction
 
   let start_options = {
         \ 'callback': funcref("s:callback"),
-        \ 'close_cb': funcref("s:close_cb"),
+        \ 'exit_cb': funcref("s:exit_cb"),
         \ }
 
   " modify GOPATH if needed