Elm local install support (#915)

* Add Elm support for npm local installation

7 files changed, 71 insertions, 5 deletions

diff --git a/README.md b/README.md
index 4919564e..e90fa28c 100644
--- a/README.md
+++ b/README.md
@@ -87,7 +87,7 @@ formatting.
 | Dart | [dartanalyzer](https://github.com/dart-lang/sdk/tree/master/pkg/analyzer_cli) |
 | Dockerfile | [hadolint](https://github.com/lukasmartinelli/hadolint) |
 | Elixir | [credo](https://github.com/rrrene/credo), [dogma](https://github.com/lpil/dogma) !! |
-| Elm | [elm-make](https://github.com/elm-lang/elm-make), [elm-format](https://github.com/avh4/elm-format) |
+| Elm | [elm-format](https://github.com/avh4/elm-format), [elm-make](https://github.com/elm-lang/elm-make) |
 | Erb | [erb](https://github.com/jeremyevans/erubi), [erubis](https://github.com/kwatch/erubis) |
 | Erlang | [erlc](http://erlang.org/doc/man/erlc.html), [SyntaxErl](https://github.com/ten0s/syntaxerl) |
 | Fortran | [gcc](https://gcc.gnu.org/) |
diff --git a/ale_linters/elm/make.vim b/ale_linters/elm/make.vim
index 04563a4d..4038e3b4 100644
--- a/ale_linters/elm/make.vim
+++ b/ale_linters/elm/make.vim
@@ -1,6 +1,15 @@
-" Author: buffalocoder - https://github.com/buffalocoder
+" Author: buffalocoder - https://github.com/buffalocoder, soywod - https://github.com/soywod
 " Description: Elm linting in Ale. Closely follows the Syntastic checker in https://github.com/ElmCast/elm-vim.
 
+call ale#Set('elm_make_executable', 'elm-make')
+call ale#Set('elm_make_use_global', 0)
+
+function! ale_linters#elm#make#GetExecutable(buffer) abort
+    return ale#node#FindExecutable(a:buffer, 'elm_make', [
+    \   'node_modules/.bin/elm-make',
+    \])
+endfunction
+
 function! ale_linters#elm#make#Handle(buffer, lines) abort
     let l:output = []
     let l:is_windows = has('win32')
@@ -52,6 +61,7 @@ endfunction
 " If it doesn't, then this will fail when imports are needed.
 function! ale_linters#elm#make#GetCommand(buffer) abort
     let l:elm_package = ale#path#FindNearestFile(a:buffer, 'elm-package.json')
+    let l:elm_exe = ale_linters#elm#make#GetExecutable(a:buffer)
     if empty(l:elm_package)
         let l:dir_set_cmd = ''
     else
@@ -63,14 +73,16 @@ function! ale_linters#elm#make#GetCommand(buffer) abort
     " a sort of flag to tell the compiler not to generate an output file,
     " which is why this is hard coded here.
     " Source: https://github.com/elm-lang/elm-make/blob/master/src/Flags.hs
-    let l:elm_cmd = 'elm-make --report=json --output='.ale#Escape('/dev/null')
+    let l:elm_cmd = ale#Escape(l:elm_exe)
+    \   . ' --report=json'
+    \   . ' --output=' . ale#Escape(g:ale#util#nul_file)
 
     return l:dir_set_cmd . ' ' . l:elm_cmd . ' %t'
 endfunction
 
 call ale#linter#Define('elm', {
 \    'name': 'make',
-\    'executable': 'elm-make',
+\    'executable_callback': 'ale_linters#elm#make#GetExecutable',
 \    'output_stream': 'both',
 \    'command_callback': 'ale_linters#elm#make#GetCommand',
 \    'callback': 'ale_linters#elm#make#Handle'
diff --git a/doc/ale-elm.txt b/doc/ale-elm.txt
index 9331575b..dff781cf 100644
--- a/doc/ale-elm.txt
+++ b/doc/ale-elm.txt
@@ -29,4 +29,22 @@ g:ale_elm_format_options                             *g:ale_elm_format_options*
   This variable can be set to pass additional options to elm-format.
 
 ===============================================================================
+elm-make                                                         *ale-elm-make*
+
+g:ale_elm_make_executable                           *g:ale_elm_make_executable*
+                                                    *b:ale_elm_make_executable*
+  Type: |String|
+  Default: `'elm-make'`
+  
+  See |ale-integrations-local-executables|
+  
+  
+g:ale_elm_make_use_global                           *g:ale_elm_make_use_global*
+                                                    *b:ale_elm_make_use_global*                                         
+  Type: |Number|
+  Default: `0`
+
+  See |ale-integrations-local-executables|
+
+===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:
diff --git a/doc/ale.txt b/doc/ale.txt
index ff02f7a6..a061f012 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -217,7 +217,7 @@ Notes:
 * Dart: `dartanalyzer`
 * Dockerfile: `hadolint`
 * Elixir: `credo`, `dogma`!!
-* Elm: `elm-make, elm-format`
+* Elm: `elm-format, elm-make`
 * Erb: `erb`, `erubis`
 * Erlang: `erlc`, `SyntaxErl`
 * Fortran: `gcc`
diff --git a/test/elm-test-files/app/filetest.elm b/test/elm-test-files/app/filetest.elm
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/test/elm-test-files/app/filetest.elm
diff --git a/test/elm-test-files/app/node_modules/.bin/elm-make b/test/elm-test-files/app/node_modules/.bin/elm-make
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/test/elm-test-files/app/node_modules/.bin/elm-make
diff --git a/test/test_elm_executable_detection.vader b/test/test_elm_executable_detection.vader
new file mode 100644
index 00000000..7b758fc2
--- /dev/null
+++ b/test/test_elm_executable_detection.vader
@@ -0,0 +1,36 @@
+Before:
+  call ale#test#SetDirectory('/testplugin/test')
+  runtime ale_linters/elm/make.vim
+
+After:
+  unlet! g:ale_elm_make_use_global
+  unlet! g:ale_elm_make_executable
+
+  call ale#test#RestoreDirectory()
+
+Execute(should get valid executable with default params):
+  call ale#test#SetFilename('elm-test-files/app/testfile.elm')
+
+  AssertEqual
+  \ g:dir . '/elm-test-files/app/node_modules/.bin/elm-make',
+  \ ale_linters#elm#make#GetExecutable(bufnr(''))
+
+Execute(should get valid executable with 'use_global' params):
+  let g:ale_elm_make_use_global = 1
+
+  call ale#test#SetFilename('elm-test-files/app/testfile.elm')
+
+  AssertEqual
+  \ 'elm-make',
+  \ ale_linters#elm#make#GetExecutable(bufnr(''))
+
+Execute(should get valid executable with 'use_global' and 'executable' params):
+  let g:ale_elm_make_executable = 'other-elm-make'
+  let g:ale_elm_make_use_global = 1
+
+  call ale#test#SetFilename('elm-test-files/app/testfile.elm')
+
+  AssertEqual
+  \ 'other-elm-make',
+  \ ale_linters#elm#make#GetExecutable(bufnr(''))
+