Add scalastyle linter (#766)

* Add support for scalastyle

* Add scalastyle docs

* scalastyle support for column numbers

* off by one column

* Add tests for scalastyle command and handler

* update readme for scalastyle

* allow full scalastyle options instead of just config file

* fix indentation

* allow scalastyle config file in parent directories by a couple names.

* check for missing match args with empty

* remove echo

* use a for loop

1 files changed, 83 insertions, 0 deletions

diff --git a/ale_linters/scala/scalastyle.vim b/ale_linters/scala/scalastyle.vim
new file mode 100644
index 00000000..ea56c0e4
--- /dev/null
+++ b/ale_linters/scala/scalastyle.vim
@@ -0,0 +1,83 @@
+" Author: Kevin Kays - https://github.com/okkays
+" Description: Support for the scalastyle checker.
+
+let g:ale_scala_scalastyle_options =
+\   get(g:, 'ale_scala_scalastyle_options', '')
+
+let g:ale_scalastyle_config_loc =
+\   get(g:, 'ale_scalastyle_config_loc', '')
+
+function! ale_linters#scala#scalastyle#Handle(buffer, lines) abort
+    " Matches patterns like the following:
+    "
+    " warning file=/home/blurble/Doop.scala message=Missing or badly formed ScalaDoc: Extra @param foobles line=190
+
+    let l:patterns = [
+    \   '^\(.\+\) .\+ message=\(.\+\) line=\(\d\+\)$',
+    \   '^\(.\+\) .\+ message=\(.\+\) line=\(\d\+\) column=\(\d\+\)$',
+    \]
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:patterns)
+        let l:args = {
+        \   'lnum': l:match[3] + 0,
+        \   'type': l:match[1] =~? 'error' ? 'E' : 'W',
+        \   'text': l:match[2]
+        \}
+
+        if !empty(l:match[4])
+            let l:args['col'] = l:match[4] + 1
+        endif
+
+        call add(l:output, l:args)
+    endfor
+
+    return l:output
+endfunction
+
+function! ale_linters#scala#scalastyle#GetCommand(buffer) abort
+    " Search for scalastyle config in parent directories.
+    let l:scalastyle_config = ''
+    let l:potential_configs = [
+    \   'scalastyle_config.xml',
+    \   'scalastyle-config.xml'
+    \]
+    for l:config in l:potential_configs
+        let l:scalastyle_config = ale#path#ResolveLocalPath(
+        \   a:buffer,
+        \   l:config,
+        \   ''
+        \)
+        if !empty(l:scalastyle_config)
+            break
+        endif
+    endfor
+
+    " If all else fails, try the global config.
+    if empty(l:scalastyle_config)
+        let l:scalastyle_config = get(g:, 'ale_scalastyle_config_loc', '')
+    endif
+
+    " Build the command using the config file and additional options.
+    let l:command = 'scalastyle'
+
+    if !empty(l:scalastyle_config)
+        let l:command .= ' --config ' . ale#Escape(l:scalastyle_config)
+    endif
+
+    if !empty(g:ale_scala_scalastyle_options)
+        let l:command .= ' ' . g:ale_scala_scalastyle_options
+    endif
+
+    let l:command .= ' %t'
+
+    return l:command
+endfunction
+
+call ale#linter#Define('scala', {
+\   'name': 'scalastyle',
+\   'executable': 'scalastyle',
+\   'output_stream': 'stdout',
+\   'command_callback': 'ale_linters#scala#scalastyle#GetCommand',
+\   'callback': 'ale_linters#scala#scalastyle#Handle',
+\})