fix(eslint): yarn 2 project cwd (#3684)

* eslint-handler: fix getcwd when there is no node_modules

autoload/ale/handlers/eslint.vim

@@ -2,10 +2,10 @@
 " Description: Functions for working with eslint, for checking or fixing files.
 
 let s:executables = [
+\   '.yarn/sdks/eslint/bin/eslint.js',
 \   'node_modules/.bin/eslint_d',
 \   'node_modules/eslint/bin/eslint.js',
 \   'node_modules/.bin/eslint',
-\   '.yarn/sdks/eslint/bin/eslint',
 \]
 let s:sep = has('win32') ? '\' : '/'
 
@@ -52,14 +52,20 @@ function! ale#handlers#eslint#GetCwd(buffer) abort
     let l:executable = ale#path#FindNearestExecutable(a:buffer, s:executables)
 
     if !empty(l:executable)
-        let l:nmi = strridx(l:executable, 'node_modules')
-        let l:project_dir = l:executable[0:l:nmi - 2]
+        let l:modules_index = strridx(l:executable, 'node_modules')
+        let l:modules_root = l:modules_index > -1 ? l:executable[0:l:modules_index - 2] : ''
+
+        let l:sdks_index = strridx(l:executable, ale#path#Simplify('.yarn/sdks'))
+        let l:sdks_root = l:sdks_index > -1 ? l:executable[0:l:sdks_index - 2] : ''
     else
         let l:modules_dir = ale#path#FindNearestDirectory(a:buffer, 'node_modules')
-        let l:project_dir = !empty(l:modules_dir) ? fnamemodify(l:modules_dir, ':h:h') : ''
+        let l:modules_root = !empty(l:modules_dir) ? fnamemodify(l:modules_dir, ':h:h') : ''
+
+        let l:sdks_dir = ale#path#FindNearestDirectory(a:buffer, ale#path#Simplify('.yarn/sdks'))
+        let l:sdks_root = !empty(l:sdks_dir) ? fnamemodify(l:sdks_dir, ':h:h:h') : ''
     endif
 
-    return !empty(l:project_dir) ? l:project_dir : ''
+    return strlen(l:modules_root) > strlen(l:sdks_root) ? l:modules_root : l:sdks_root
 endfunction
 
 function! ale#handlers#eslint#GetCommand(buffer) abort

test/linter/test_eslint.vader

@@ -66,11 +66,20 @@ Execute(eslint.js executables should be run with node on Windows):
   \ (has('win32') ? ale#Escape('node.exe') . ' ' : '')
   \ . ale#Escape(b:executable) . b:args
 
-Execute(eslint.js should be run from a containing project with eslint):
+Execute(eslint.js should be run from a containing project with node_modules):
   call ale#test#SetFilename('../test-files/eslint/react-app/subdir-with-package-json/testfile.js')
 
   let b:executable = ale#path#Simplify(g:dir . '/../test-files/eslint/react-app/node_modules/eslint/bin/eslint.js')
   AssertLinterCwd ale#path#Simplify(g:dir . '/../test-files/eslint/react-app')
   AssertLinter b:executable,
   \ (has('win32') ? ale#Escape('node.exe') . ' ' : '')
   \ . ale#Escape(b:executable) . b:args
+
+Execute(eslint.js should be run from a containing project with .yarn/sdks):
+  call ale#test#SetFilename('../test-files/eslint/yarn2-app/subdir/testfile.js')
+
+  let b:executable = ale#path#Simplify(g:dir . '/../test-files/eslint/yarn2-app/.yarn/sdks/eslint/bin/eslint.js')
+  AssertLinterCwd ale#path#Simplify(g:dir . '/../test-files/eslint/yarn2-app')
+  AssertLinter b:executable,
+  \ (has('win32') ? ale#Escape('node.exe') . ' ' : '')
+  \ . ale#Escape(b:executable) . b:args