#927 Allow b:ale_linter_aliases to be set to a String

autoload/ale/linter.vim

@@ -346,8 +346,9 @@ endfunction
 function! s:GetAliasedFiletype(original_filetype) abort
     let l:buffer_aliases = get(b:, 'ale_linter_aliases', {})
 
-    " b:ale_linter_aliases can be set to a List.
+    " b:ale_linter_aliases can be set to a List or String.
     if type(l:buffer_aliases) is v:t_list
+    \|| type(l:buffer_aliases) is v:t_string
         return l:buffer_aliases
     endif
 

doc/ale.txt

@@ -1310,10 +1310,12 @@ g:ale_linter_aliases                                     *g:ale_linter_aliases*
   ALE will first look for aliases for filetypes in the `b:ale_linter_aliases`
   variable, then `g:ale_linter_aliases`, and then a default Dictionary.
 
-  `b:ale_linter_aliases` can be set to a |List|, to tell ALE to load the
-  linters for specific filetypes for a given buffer. >
+  `b:ale_linter_aliases` can be set to a |List| or a |String|, to tell ALE to
+  load the linters for specific filetypes for a given buffer. >
 
   let b:ale_linter_aliases = ['html', 'javascript', 'css']
+  " OR, Alias a filetype to only a single filetype with a String.
+  let b:ale_linter_aliases = 'javascript'
 <
   No linters will be loaded when the buffer's filetype is empty.
 

test/test_linter_retrieval.vader

@@ -130,6 +130,8 @@ Execute (The local alias option shouldn't completely replace the global one):
   " global Dictionary.
   let b:ale_linter_aliases = {'testft3': ['testft1']}
 
+  AssertEqual [g:testlinter1, g:testlinter2], ale#linter#Get('testft1')
+
 Execute (Lists should be accepted for local aliases):
   call ale#linter#Define('testft1', g:testlinter1)
   call ale#linter#Define('testft2', g:testlinter2)
@@ -139,6 +141,15 @@ Execute (Lists should be accepted for local aliases):
 
   AssertEqual [g:testlinter2], ale#linter#Get('anything.else')
 
+Execute (Strings should be accepted for local aliases):
+  call ale#linter#Define('testft1', g:testlinter1)
+  call ale#linter#Define('testft2', g:testlinter2)
+  let g:ale_linter_aliases = {'testft1': ['testft1', 'testft2']}
+  " We should load the testft2 linters for this buffer, with no duplicates.
+  let b:ale_linter_aliases = 'testft2'
+
+  AssertEqual [g:testlinter2], ale#linter#Get('anything.else')
+
 Execute (Buffer-local overrides for aliases should be used):
   call ale#linter#Define('testft1', g:testlinter1)
   call ale#linter#Define('testft2', g:testlinter2)