feat(erlang) support for elp language server

ale_linters/erlang/elp.vim

@@ -0,0 +1,36 @@
+" Author: Ivan Stone <istone@snap.com>
+" Description: LSP linter for Erlang files using erlang-language-platform
+
+call ale#Set('erlang_elp_executable', 'elp')
+
+function! s:FindProjectRoot(buffer) abort
+    let l:markers = [
+    \   '_checkouts/',
+    \   '_build/',
+    \   'deps/',
+    \   'rebar.config',
+    \   'rebar.lock',
+    \   'erlang.mk',
+    \   '.kerl_config',
+    \]
+
+    for l:marker in l:markers
+        let l:path = l:marker[-1:] is# '/'
+        \   ? ale#path#FindNearestDirectory(a:buffer, l:marker)
+        \   : ale#path#FindNearestFile(a:buffer, l:marker)
+
+        if !empty(l:path)
+            return ale#path#Dirname(l:path)
+        endif
+    endfor
+
+    return ''
+endfunction
+
+call ale#linter#Define('erlang', {
+\   'name': 'elp',
+\   'lsp': 'stdio',
+\   'executable': {b -> ale#Var(b, 'erlang_elp_executable')},
+\   'command': '%e server',
+\   'project_root': function('s:FindProjectRoot'),
+\})

doc/ale-erlang.txt

@@ -64,6 +64,20 @@ g:ale_erlang_elvis_executable
   This variable can be changed to specify the elvis executable.
 
 
+===============================================================================
+elp                                                          *ale-erlang-elp*
+
+                                          *ale-options.erlang_elp_executable*
+                                                *g:ale_erlang_elp_executable*
+                                                *b:ale_erlang_elp_executable*
+erlang_elp_executable
+g:ale_erlang_elp_executable
+  Type: |String|
+  Default: `'elp'`
+
+  This variable can be changed to specify the elp executable.
+
+
 ===============================================================================
 erlang-mode                                            *ale-erlang-erlang-mode*
 

doc/ale-supported-languages-and-tools.txt

@@ -198,6 +198,7 @@ Notes:
 * Erlang
   * `SyntaxErl`
   * `dialyzer`!!
+  * `elp`
   * `elvis`!!
   * `erlang-mode` (The Erlang mode for Emacs)
   * `erlang_ls`

doc/ale.txt

@@ -3544,6 +3544,7 @@ documented in additional help files.
     elm-make..............................|ale-elm-elm-make|
   erlang..................................|ale-erlang-options|
     dialyzer..............................|ale-erlang-dialyzer|
+    elp...................................|ale-erlang-elp|
     elvis.................................|ale-erlang-elvis|
     erlang-mode...........................|ale-erlang-erlang-mode|
     erlang_ls.............................|ale-erlang-erlang_ls|

supported-tools.md

@@ -208,6 +208,7 @@ formatting.
 * Erlang
   * [SyntaxErl](https://github.com/ten0s/syntaxerl)
   * [dialyzer](http://erlang.org/doc/man/dialyzer.html) :floppy_disk:
+  * [elp](https://github.com/WhatsApp/erlang-language-platform) :speech_balloon:
   * [elvis](https://github.com/inaka/elvis) :floppy_disk:
   * [erlang-mode](https://www.erlang.org/doc/apps/tools/erlang_mode_chapter.html) (The Erlang mode for Emacs) :speech_balloon:
   * [erlang_ls](https://github.com/erlang-ls/erlang_ls) :speech_balloon:

test/linter/test_erlang_elp.vader

@@ -0,0 +1,42 @@
+Before:
+  call ale#assert#SetUpLinterTest('erlang', 'elp')
+
+After:
+  unlet! b:root
+
+  call ale#assert#TearDownLinterTest()
+
+Execute(The default command should be correct):
+  AssertLinter 'elp', ale#Escape('elp') . ' server'
+
+Execute(Executable should be configurable):
+  let b:ale_erlang_elp_executable = '/path/to/elp'
+
+  AssertLinter '/path/to/elp', ale#Escape('/path/to/elp') . ' server'
+
+Execute(Root of Rebar3 project should be detected):
+  let b:root = '../test-files/erlang/rebar3_app'
+
+  call ale#test#SetFilename(b:root . '/src/app.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)
+
+  call ale#test#SetFilename(b:root . '/_build/default/lib/dep/src/dep.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)
+
+  call ale#test#SetFilename(b:root . '/_checkouts/dep/src/dep.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)
+
+Execute(Root of Erlang.mk project should be detected):
+  let b:root = '../test-files/erlang/erlang_mk_app'
+
+  call ale#test#SetFilename(b:root . '/src/app.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)
+
+  call ale#test#SetFilename(b:root . '/deps/dep/src/dep.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)
+
+Execute(Root of kerl managed Erlang/OTP installation should be detected):
+  let b:root = '../test-files/erlang/kerl_otp_root'
+
+  call ale#test#SetFilename(b:root . '/lib/stdlib-4.1.1/array.erl')
+  AssertLSPProject ale#test#GetFilename(b:root)