Add better support for Haskell stack compiler tools (#1851)

* Add better support for Haskell stack compiler tools

This commit adds support for `stack` as the executable of a tool. This
follows a pattern that has been implemented for `bundler`'s tool chain.

* Move hlint command to linter file
* Add vader test for stack exec handling
* Update ghc-mod to support stack execution

`ghc-mod` was previously broken into 2 linters.

1. ghc_mod
2. stack_ghc_mod

This additional linter is not necessary with proper support for
executable variables and `stack exec` handling.

* Support stack exec in hfmt
* Support stack in hdevtools

18 files changed, 104 insertions, 48 deletions

diff --git a/README.md b/README.md
index bdde278f..0eeaf514 100644
--- a/README.md
+++ b/README.md
@@ -129,7 +129,7 @@ formatting.
 | Hack | [hack](http://hacklang.org/), [hackfmt](https://github.com/facebook/hhvm/tree/master/hphp/hack/hackfmt), [hhast](https://github.com/hhvm/hhast) (disabled by default; see `:help ale-integration-hack`) |
 | Haml | [haml-lint](https://github.com/brigade/haml-lint) |
 | Handlebars | [ember-template-lint](https://github.com/rwjblue/ember-template-lint) |
-| Haskell | [brittany](https://github.com/lspitzner/brittany), [ghc](https://www.haskell.org/ghc/), [cabal-ghc](https://www.haskell.org/cabal/), [stylish-haskell](https://github.com/jaspervdj/stylish-haskell), [stack-ghc](https://haskellstack.org/), [stack-build](https://haskellstack.org/) !!, [ghc-mod](https://github.com/DanielG/ghc-mod), [stack-ghc-mod](https://github.com/DanielG/ghc-mod), [hlint](https://hackage.haskell.org/package/hlint), [hdevtools](https://hackage.haskell.org/package/hdevtools), [hfmt](https://github.com/danstiner/hfmt), [hie](https://github.com/haskell/haskell-ide-engine) |
+| Haskell | [brittany](https://github.com/lspitzner/brittany), [ghc](https://www.haskell.org/ghc/), [cabal-ghc](https://www.haskell.org/cabal/), [stylish-haskell](https://github.com/jaspervdj/stylish-haskell), [stack-ghc](https://haskellstack.org/), [stack-build](https://haskellstack.org/) !!, [ghc-mod](https://github.com/DanielG/ghc-mod), [hlint](https://hackage.haskell.org/package/hlint), [hdevtools](https://hackage.haskell.org/package/hdevtools), [hfmt](https://github.com/danstiner/hfmt), [hie](https://github.com/haskell/haskell-ide-engine) |
 | HTML | [alex](https://github.com/wooorm/alex) !!, [HTMLHint](http://htmlhint.com/), [proselint](http://proselint.com/), [tidy](http://www.html-tidy.org/), [write-good](https://github.com/btford/write-good) |
 | Idris | [idris](http://www.idris-lang.org/) |
 | Java | [checkstyle](http://checkstyle.sourceforge.net), [javac](http://www.oracle.com/technetwork/java/javase/downloads/index.html), [google-java-format](https://github.com/google/google-java-format), [PMD](https://pmd.github.io/), [javalsp](https://github.com/georgewfraser/vscode-javac), [uncrustify](https://github.com/uncrustify/uncrustify) |
diff --git a/ale_linters/haskell/ghc-mod.vim b/ale_linters/haskell/ghc-mod.vim
deleted file mode 100644
index eb032f50..00000000
--- a/ale_linters/haskell/ghc-mod.vim
+++ /dev/null
@@ -1,18 +0,0 @@
-" Author: wizzup <wizzup@gmail.com>
-" Description: ghc-mod for Haskell files
-
-call ale#linter#Define('haskell', {
-\   'name': 'ghc_mod',
-\   'aliases': ['ghc-mod'],
-\   'executable': 'ghc-mod',
-\   'command': 'ghc-mod --map-file %s=%t check %s',
-\   'callback': 'ale#handlers#haskell#HandleGHCFormat',
-\})
-
-call ale#linter#Define('haskell', {
-\   'name': 'stack_ghc_mod',
-\   'aliases': ['stack-ghc-mod'],
-\   'executable': 'stack',
-\   'command': 'stack exec ghc-mod -- --map-file %s=%t check %s',
-\   'callback': 'ale#handlers#haskell#HandleGHCFormat',
-\})
diff --git a/ale_linters/haskell/ghc_mod.vim b/ale_linters/haskell/ghc_mod.vim
new file mode 100644
index 00000000..9762be7a
--- /dev/null
+++ b/ale_linters/haskell/ghc_mod.vim
@@ -0,0 +1,19 @@
+" Author: wizzup <wizzup@gmail.com>
+" Description: ghc-mod for Haskell files
+
+call ale#Set('haskell_ghc_mod_executable', 'ghc-mod')
+
+function! ale_linters#haskell#ghc_mod#GetCommand (buffer) abort
+    let l:executable = ale#Var(a:buffer, 'haskell_ghc_mod_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'ghc-mod')
+    \   . ' --map-file %s=%t check %s'
+endfunction
+
+call ale#linter#Define('haskell', {
+\   'name': 'ghc_mod',
+\   'aliases': ['ghc-mod'],
+\   'executable_callback': ale#VarFunc('haskell_ghc_mod_executable'),
+\   'command_callback': 'ale_linters#haskell#ghc_mod#GetCommand',
+\   'callback': 'ale#handlers#haskell#HandleGHCFormat',
+\})
diff --git a/ale_linters/haskell/hdevtools.vim b/ale_linters/haskell/hdevtools.vim
index fbd5278e..cc5ce56f 100644
--- a/ale_linters/haskell/hdevtools.vim
+++ b/ale_linters/haskell/hdevtools.vim
@@ -5,7 +5,10 @@ call ale#Set('haskell_hdevtools_executable', 'hdevtools')
 call ale#Set('haskell_hdevtools_options', get(g:, 'hdevtools_options', '-g -Wall'))
 
 function! ale_linters#haskell#hdevtools#GetCommand(buffer) abort
-    return '%e check' . ale#Pad(ale#Var(a:buffer, 'haskell_hdevtools_options'))
+    let l:executable = ale#Var(a:buffer, 'haskell_hdevtools_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hdevtools')
+    \ . ' check' . ale#Pad(ale#Var(a:buffer, 'haskell_hdevtools_options'))
     \ . ' -p %s %t'
 endfunction
 
diff --git a/ale_linters/haskell/hie.vim b/ale_linters/haskell/hie.vim
index 558d36a3..3ff1180a 100644
--- a/ale_linters/haskell/hie.vim
+++ b/ale_linters/haskell/hie.vim
@@ -3,10 +3,6 @@
 
 call ale#Set('haskell_hie_executable', 'hie')
 
-function! ale_linters#haskell#hie#GetExecutable(buffer) abort
-    return ale#Var(a:buffer, 'haskell_hie_executable')
-endfunction
-
 function! ale_linters#haskell#hie#GetProjectRoot(buffer) abort
     " Search for the stack file first
     let l:project_file = ale#path#FindNearestFile(a:buffer, 'stack.yaml')
@@ -35,10 +31,17 @@ function! ale_linters#haskell#hie#GetProjectRoot(buffer) abort
     return l:project_file
 endfunction
 
+function! ale_linters#haskell#hie#GetCommand(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'haskell_hie_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hie')
+\        . ' --lsp'
+endfunction
+
 call ale#linter#Define('haskell', {
 \   'name': 'hie',
 \   'lsp': 'stdio',
-\   'command': '%e --lsp',
-\   'executable_callback': 'ale_linters#haskell#hie#GetExecutable',
+\   'command_callback': 'ale_linters#haskell#hie#GetCommand',
+\   'executable_callback': ale#VarFunc('haskell_hie_executable'),
 \   'project_root_callback': 'ale_linters#haskell#hie#GetProjectRoot',
 \})
diff --git a/ale_linters/haskell/hlint.vim b/ale_linters/haskell/hlint.vim
index 3ee864bf..fbb49fdb 100644
--- a/ale_linters/haskell/hlint.vim
+++ b/ale_linters/haskell/hlint.vim
@@ -1,9 +1,6 @@
 " Author: jparoz <jesse.paroz@gmail.com>
 " Description: hlint for Haskell files
 
-call ale#Set('haskell_hlint_executable', 'hlint')
-call ale#Set('haskell_hlint_options', get(g:, 'hlint_options', ''))
-
 function! ale_linters#haskell#hlint#Handle(buffer, lines) abort
     let l:output = []
 
@@ -32,14 +29,15 @@ endfunction
 function! ale_linters#haskell#hlint#GetCommand(buffer) abort
     let l:hlintopts = '--color=never --json'
 
-    return '%e'
+    return ale#handlers#hlint#GetExecutable(a:buffer)
     \      . ' ' . ale#Var(a:buffer, 'haskell_hlint_options')
-    \      . ' ' . l:hlintopts . ' -'
+    \      . ' ' . l:hlintopts
+    \      . ' -'
 endfunction
 
 call ale#linter#Define('haskell', {
 \   'name': 'hlint',
 \   'executable_callback': ale#VarFunc('haskell_hlint_executable'),
-\   'command_callback': 'ale_linters#haskell#hlint#GetCommand',
+\   'command_callback': 'ale_linters#haskell#hlint#GetCommand' ,
 \   'callback': 'ale_linters#haskell#hlint#Handle',
 \})
diff --git a/autoload/ale/fixers/brittany.vim b/autoload/ale/fixers/brittany.vim
index 57c77325..c2448348 100644
--- a/autoload/ale/fixers/brittany.vim
+++ b/autoload/ale/fixers/brittany.vim
@@ -3,11 +3,17 @@
 
 call ale#Set('haskell_brittany_executable', 'brittany')
 
-function! ale#fixers#brittany#Fix(buffer) abort
+function! ale#fixers#brittany#GetExecutable(buffer) abort
     let l:executable = ale#Var(a:buffer, 'haskell_brittany_executable')
 
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'brittany')
+endfunction
+
+function! ale#fixers#brittany#Fix(buffer) abort
+    let l:executable = ale#fixers#brittany#GetExecutable(a:buffer)
+
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': l:executable
     \       . ' --write-mode inplace'
     \       . ' %t',
     \   'read_temporary_file': 1,
diff --git a/autoload/ale/fixers/hfmt.vim b/autoload/ale/fixers/hfmt.vim
index ea061da4..0407b713 100644
--- a/autoload/ale/fixers/hfmt.vim
+++ b/autoload/ale/fixers/hfmt.vim
@@ -7,7 +7,7 @@ function! ale#fixers#hfmt#Fix(buffer) abort
     let l:executable = ale#Var(a:buffer, 'haskell_hfmt_executable')
 
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hfmt')
     \       . ' -w'
     \       . ' %t',
     \   'read_temporary_file': 1,
diff --git a/autoload/ale/fixers/hlint.vim b/autoload/ale/fixers/hlint.vim
index 94dd736e..88779a55 100644
--- a/autoload/ale/fixers/hlint.vim
+++ b/autoload/ale/fixers/hlint.vim
@@ -1,13 +1,10 @@
 " Author: eborden <evan@evan-borden.com>
 " Description: Integration of hlint refactor with ALE.
 "
-call ale#Set('haskell_hlint_executable', 'hlint')
 
 function! ale#fixers#hlint#Fix(buffer) abort
-    let l:executable = ale#Var(a:buffer, 'haskell_hlint_executable')
-
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': ale#handlers#hlint#GetExecutable(a:buffer)
     \       . ' --refactor'
     \       . ' --refactor-options="--inplace"'
     \       . ' %t',
diff --git a/autoload/ale/fixers/stylish_haskell.vim b/autoload/ale/fixers/stylish_haskell.vim
index a352312f..ce71c1ce 100644
--- a/autoload/ale/fixers/stylish_haskell.vim
+++ b/autoload/ale/fixers/stylish_haskell.vim
@@ -3,11 +3,17 @@
 "
 call ale#Set('haskell_stylish_haskell_executable', 'stylish-haskell')
 
-function! ale#fixers#stylish_haskell#Fix(buffer) abort
+function! ale#fixers#stylish_haskell#GetExecutable(buffer) abort
     let l:executable = ale#Var(a:buffer, 'haskell_stylish_haskell_executable')
 
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'stylish-haskell')
+endfunction
+
+function! ale#fixers#stylish_haskell#Fix(buffer) abort
+    let l:executable = ale#fixers#stylish_haskell#GetExecutable(a:buffer)
+
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': l:executable
     \       . ' --inplace'
     \       . ' %t',
     \   'read_temporary_file': 1,
diff --git a/autoload/ale/handlers/haskell_stack.vim b/autoload/ale/handlers/haskell_stack.vim
new file mode 100644
index 00000000..108301a9
--- /dev/null
+++ b/autoload/ale/handlers/haskell_stack.vim
@@ -0,0 +1,7 @@
+function! ale#handlers#haskell_stack#EscapeExecutable(executable, stack_exec) abort
+    let l:exec_args = a:executable =~? 'stack$'
+    \   ? ' exec ' . ale#Escape(a:stack_exec) . ' --'
+    \   : ''
+
+    return ale#Escape(a:executable) . l:exec_args
+endfunction
diff --git a/autoload/ale/handlers/hlint.vim b/autoload/ale/handlers/hlint.vim
new file mode 100644
index 00000000..b9a8c322
--- /dev/null
+++ b/autoload/ale/handlers/hlint.vim
@@ -0,0 +1,8 @@
+call ale#Set('haskell_hlint_executable', 'hlint')
+call ale#Set('haskell_hlint_options', get(g:, 'hlint_options', ''))
+
+function! ale#handlers#hlint#GetExecutable(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'haskell_hlint_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hlint')
+endfunction
diff --git a/doc/ale-haskell.txt b/doc/ale-haskell.txt
index a59fa4e2..a4db683b 100644
--- a/doc/ale-haskell.txt
+++ b/doc/ale-haskell.txt
@@ -23,6 +23,16 @@ g:ale_haskell_ghc_options                           *g:ale_haskell_ghc_options*
   This variable can be changed to modify flags given to ghc.
 
 ===============================================================================
+ghc-mod                                                   *ale-haskell-ghc-mod*
+
+g:ale_haskell_ghc_mod_executable             *g:ale_haskell_ghc_mod_executable*
+                                             *b:ale_haskell_ghc_mod_executable*
+  Type: |String|
+  Default: `'ghc-mod'`
+
+  This variable can be changed to use a different executable for ghc-mod.
+
+===============================================================================
 cabal-ghc                                               *ale-haskell-cabal-ghc*
 
 g:ale_haskell_cabal_ghc_options               *g:ale_haskell_cabal_ghc_options*
diff --git a/doc/ale.txt b/doc/ale.txt
index ec44f3b8..3c561e2f 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -117,6 +117,7 @@ CONTENTS                                                         *ale-contents*
     haskell...............................|ale-haskell-options|
       brittany............................|ale-haskell-brittany|
       ghc.................................|ale-haskell-ghc|
+      ghc-mod.............................|ale-haskell-ghc-mod|
       cabal-ghc...........................|ale-haskell-cabal-ghc|
       hdevtools...........................|ale-haskell-hdevtools|
       hfmt................................|ale-haskell-hfmt|
@@ -411,7 +412,7 @@ Notes:
 * Hack: `hack`, `hackfmt`, `hhast`
 * Haml: `haml-lint`
 * Handlebars: `ember-template-lint`
-* Haskell: `brittany`, `ghc`, `cabal-ghc`, `stylish-haskell`, `stack-ghc`, `stack-build`!!, `ghc-mod`, `stack-ghc-mod`, `hlint`, `hdevtools`, `hfmt`, `hie`
+* Haskell: `brittany`, `ghc`, `cabal-ghc`, `stylish-haskell`, `stack-ghc`, `stack-build`!!, `ghc-mod`, `hlint`, `hdevtools`, `hfmt`, `hie`
 * HTML: `alex`!!, `HTMLHint`, `proselint`, `tidy`, `write-good`
 * Idris: `idris`
 * Java: `checkstyle`, `javac`, `google-java-format`, `PMD`, `javalsp`, `uncrustify`
diff --git a/test/command_callback/test_haskell_ghc_mod_command_callbacks.vader b/test/command_callback/test_haskell_ghc_mod_command_callbacks.vader
new file mode 100644
index 00000000..c1cc8597
--- /dev/null
+++ b/test/command_callback/test_haskell_ghc_mod_command_callbacks.vader
@@ -0,0 +1,10 @@
+Before:
+  call ale#assert#SetUpLinterTest('haskell', 'ghc_mod')
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(Default should use ghc-mod):
+  AssertLinter
+  \ 'ghc-mod',
+  \ ale#Escape('ghc-mod') . ' --map-file %s=%t check %s'
diff --git a/test/command_callback/test_haskell_hlint_command_callbacks.vader b/test/command_callback/test_haskell_hlint_command_callbacks.vader
index fb354ed4..d4ee708c 100644
--- a/test/command_callback/test_haskell_hlint_command_callbacks.vader
+++ b/test/command_callback/test_haskell_hlint_command_callbacks.vader
@@ -1,5 +1,9 @@
 Before:
   call ale#assert#SetUpLinterTest('haskell', 'hlint')
+
+  let g:ale_haskell_hlint_executable = 'hlint'
+  let g:ale_haskell_hlint_options = ''
+
   let b:base_opts = '--color=never --json -'
 
 After:
diff --git a/test/fixers/test_hlint_fixer_callback.vader b/test/fixers/test_hlint_fixer_callback.vader
index 48f26c7c..08f08fae 100644
--- a/test/fixers/test_hlint_fixer_callback.vader
+++ b/test/fixers/test_hlint_fixer_callback.vader
@@ -1,9 +1,4 @@
 Before:
-  Save g:ale_haskell_hlint_executable
-
-  " Use an invalid global executable, so we don't match it.
-  let g:ale_haskell_hlint_executable = 'xxxinvalid'
-
   call ale#test#SetDirectory('/testplugin/test/fixers')
 
 After:
@@ -17,7 +12,7 @@ Execute(The hlint callback should return the correct default values):
   AssertEqual
   \ {
   \   'read_temporary_file': 1,
-  \   'command': ale#Escape('xxxinvalid')
+  \   'command': ale#Escape('hlint')
   \     . ' --refactor'
   \     . ' --refactor-options="--inplace"'
   \     . ' %t',
diff --git a/test/handler/test_haskell_stack_handler.vader b/test/handler/test_haskell_stack_handler.vader
new file mode 100644
index 00000000..07e7e69c
--- /dev/null
+++ b/test/handler/test_haskell_stack_handler.vader
@@ -0,0 +1,7 @@
+Before:
+  runtime ale/handlers/haskell_stack.vim
+
+Execute(Escape stack should correctly identify a stack exec command):
+  AssertEqual
+  \ ale#Escape('stack') . ' exec ' . ale#Escape('hlint') . ' --',
+  \ ale#handlers#haskell_stack#EscapeExecutable('stack', 'hlint')