Fix #283 Add an option for using ch_sendraw(), which can be better for some users

autoload/ale/engine.vim

@@ -266,22 +266,23 @@ function! s:RunJob(options) abort
             let l:job_options.out_cb = function('s:GatherOutputVim')
         endif
 
-        if has('win32')
-            " job_start commands on Windows have to be run with cmd /c,
-            " othwerwise %PATHTEXT% will not be used to programs ending int
-            " .cmd, .bat, .exe, etc.
-            let l:command = 'cmd /c ' . l:command
-        else
-            " Execute the command with the shell, to fix escaping issues.
-            let l:command = split(&shell) + split(&shellcmdflag) + [l:command]
+        " The command will be executed in a subshell. This fixes a number of
+        " issues, including reading the PATH variables correctly, %PATHEXT%
+        " expansion on Windows, etc.
+        "
+        " NeoVim handles this issue automatically if the command is a String.
+        let l:command = has('win32')
+        \   ?  'cmd /c ' . l:command
+        \   : split(&shell) + split(&shellcmdflag) + [l:command]
 
-            if l:read_buffer
+        if l:read_buffer && !g:ale_use_ch_sendraw
+            " Send the buffer via internal Vim 8 mechanisms, rather than
+            " by reading and sending it ourselves.
             " On Unix machines, we can send the Vim buffer directly.
             " This is faster than reading the lines ourselves.
             let l:job_options.in_io = 'buffer'
             let l:job_options.in_buf = l:buffer
         endif
-        endif
 
         " Vim 8 will read the stdin from the file's buffer.
         let l:job = job_start(l:command, l:job_options)
@@ -307,7 +308,7 @@ function! s:RunJob(options) abort
 
                 call jobsend(l:job, l:input)
                 call jobclose(l:job, 'stdin')
-            elseif has('win32')
+            elseif g:ale_use_ch_sendraw
                 " On some Vim versions, we have to send the buffer data ourselves.
                 let l:input = join(getbufline(l:buffer, 1, '$'), "\n") . "\n"
                 let l:channel = job_getchannel(l:job)

doc/ale.txt

@@ -395,6 +395,22 @@ g:ale_statusline_format                               *g:ale_statusline_format*
   - The 3rd element is for when no errors are detected
 
 
+g:ale_use_ch_sendraw                                     *g:ale_use_ch_sendraw*
+
+  Type: |Number|
+  Default: `has('win32')`
+
+  This option only applies to Vim, and is ignored when the plugin is run
+  in NeoVim.
+
+  When this option is set to `1`, ALE will use |ch_sendraw()| for sending text
+  buffers to jobs, instead of setting the `in_io` option to `'buffer'` for
+  |job_start()|. See |in_io-buffer| for more information on this Vim option.
+
+  Using |ch_sendraw()| instead may lead to better performance or stability in
+  some cases. Typically for Linux users, `in_io` seems to be a better option.
+
+
 g:ale_warn_about_trailing_whitespace     *g:ale_warn_about_trailing_whitespace*
 
   Type: |Number|

plugin/ale.vim

@@ -66,6 +66,10 @@ let g:ale_lint_on_save = get(g:, 'ale_lint_on_save', 0)
 " should be used instead.
 let g:ale_enabled = get(g:, 'ale_enabled', 1)
 
+" This flag can be used to force ALE to send buffer data using ch_sendraw
+" in Vim 8. This works better for some users.
+let g:ale_use_ch_sendraw = get(g:, 'ale_use_ch_sendraw', has('win32'))
+
 " These flags dictates if ale uses the quickfix or the loclist (loclist is the
 " default, quickfix overrides loclist).
 let g:ale_set_loclist = get(g:, 'ale_set_loclist', 1)

test/smoke_test.vader

@@ -0,0 +1,68 @@
+Before:
+  function! TestCallback(buffer, output)
+    return [{
+    \ 'bufnr': a:buffer,
+    \ 'lnum': 2,
+    \ 'vcol': 0,
+    \ 'col': 3,
+    \ 'text': a:output[0],
+    \ 'type': 'E',
+    \ 'nr': -1,
+    \}]
+  endfunction
+
+  call ale#linter#Define('foobar', {
+  \ 'name': 'testlinter',
+  \ 'callback': 'TestCallback',
+  \ 'executable': 'echo',
+  \ 'command': 'echo foo bar',
+  \})
+
+After:
+  let g:ale_use_ch_sendraw = 0
+  let g:ale_buffer_info = {}
+  delfunction TestCallback
+  call ale#linter#Reset()
+
+Given foobar (Some imaginary filetype):
+  foo
+  bar
+  baz
+
+Execute(Linters should run with the default options):
+  AssertEqual 'foobar', &filetype
+
+  call ale#Lint()
+  call ale#engine#WaitForJobs(2000)
+
+  AssertEqual [{
+  \   'bufnr': bufnr('%'),
+  \   'lnum': 2,
+  \   'vcol': 0,
+  \   'col': 3,
+  \   'text': 'foo bar',
+  \   'type': 'E',
+  \   'nr': -1,
+  \   'pattern': '',
+  \   'valid': 1,
+  \ }], getloclist(0)
+
+Execute(Linters should run with `let g:ale_use_ch_sendraw = 1`):
+  AssertEqual 'foobar', &filetype
+
+  let g:ale_use_ch_sendraw = 1
+
+  call ale#Lint()
+  call ale#engine#WaitForJobs(2000)
+
+  AssertEqual [{
+  \   'bufnr': bufnr('%'),
+  \   'lnum': 2,
+  \   'vcol': 0,
+  \   'col': 3,
+  \   'text': 'foo bar',
+  \   'type': 'E',
+  \   'nr': -1,
+  \   'pattern': '',
+  \   'valid': 1,
+  \ }], getloclist(0)