Add support for multiple filetypes in filetype aliasing

autoload/ale/linter.vim

@@ -174,26 +174,25 @@ function! ale#linter#Define(filetype, linter) abort
     call add(s:linters[a:filetype], l:new_linter)
 endfunction
 
-function! ale#linter#GetAll(filetype) abort
-    if a:filetype ==# ''
-        " Empty filetype? Nothing to be done about that.
-        return []
-    endif
+function! ale#linter#GetAll(filetypes) abort
+    let l:combined_linters = []
 
-    if has_key(s:linters, a:filetype)
-        " We already loaded the linter files for this filetype, so stop here.
-        return s:linters[a:filetype]
-    endif
+    for l:filetype in a:filetypes
+        " Haven't we loaded the linter files for this filetype yet?
+        if !has_key(s:linters, l:filetype)
+            " So load it
+            execute 'silent! runtime! ale_linters/' . l:filetype . '/*.vim'
 
-    " Load all linters for a given filetype.
-    execute 'silent! runtime! ale_linters/' . a:filetype . '/*.vim'
+            " Still don't have the linter files? There must be occured an error
+            if !has_key(s:linters, l:filetype)
+                let s:linters[l:filetype] = []
+            endif
+        endif
 
-    if !has_key(s:linters, a:filetype)
-        " If we couldn't load any linters, let everyone know.
-        let s:linters[a:filetype] = []
-    endif
+        call extend(l:combined_linters, get(s:linters, l:filetype, []))
+    endfor
 
-    return s:linters[a:filetype]
+    return l:combined_linters
 endfunction
 
 function! ale#linter#ResolveFiletype(original_filetype) abort
@@ -209,6 +208,10 @@ function! ale#linter#ResolveFiletype(original_filetype) abort
     \   )
     \)
 
+    if type(l:filetype) != type([])
+        return [l:filetype]
+    endif
+
     return l:filetype
 endfunction
 

doc/ale.txt

@@ -380,6 +380,14 @@ g:ale_linter_aliases                                     *g:ale_linter_aliases*
   not the aliased type (`'php'`). This allows an aliased type to run a
   different set of linters from the type it is being mapped to.
 
+  Passing a list of filetypes is also supported. Say you want to lint
+  javascript and css embedded in HTML (using linters that support that).
+  You could alias `html` like so:
+
+  `let g:ale_linter_aliases = {'html': ['html', 'javascript', 'css']}`
+
+  Note that `html` itself was included as an alias. That is because aliases
+  will override the original linters for the aliased filetepe.
 
 g:ale_linters                                                   *g:ale_linters*
 

test/test_linter_retrieval.vader

@@ -39,5 +39,19 @@ Execute (Define multiple linters for different filetypes):
 Then (Linters for dot-seperated filetypes should be properly handled):
   AssertEqual [g:testlinter1, g:testlinter2], ale#linter#Get('testft1.testft2')
 
+Execute (Define multiple aliases for a filetype):
+  call ale#linter#Define('testft1', g:testlinter1)
+  call ale#linter#Define('testft2', g:testlinter2)
+  let ale_linter_aliases = {'testft3': ['testft1', 'testft2']}
+Then (Linters should be transparently aliased):
+  AssertEqual [g:testlinter1, g:testlinter2], ale#linter#Get('testft3')
+
+Execute (Alias a filetype to itself plus another one):
+  call ale#linter#Define('testft1', g:testlinter1)
+  call ale#linter#Define('testft2', g:testlinter2)
+  let ale_linter_aliases = {'testft1': ['testft1', 'testft2']}
+Then (The original linters should still be there):
+  AssertEqual [g:testlinter1, g:testlinter2], ale#linter#Get('testft1')
+
 Execute (Try to load a linter from disk):
   AssertEqual [{'name': 'testlinter', 'output_stream': 'stdout', 'executable': 'testlinter', 'command': 'testlinter', 'callback': 'testCB', 'read_buffer': 1, 'lint_file': 0}], ale#linter#Get('testft')