Fix #924 - Make changing the sign column color work again

autoload/ale/sign.vim

@@ -184,16 +184,6 @@ function! s:GroupLoclistItems(buffer, loclist) abort
     return l:grouped_items
 endfunction
 
-function! ale#sign#SetSignColumnHighlight(has_problems) abort
-    highlight clear SignColumn
-
-    if a:has_problems
-        highlight link SignColumn ALESignColumnWithErrors
-    else
-        highlight link SignColumn ALESignColumnWithoutErrors
-    endif
-endfunction
-
 function! s:UpdateLineNumbers(buffer, current_sign_list, loclist) abort
     let l:line_map = {}
     let l:line_numbers_changed = 0
@@ -347,7 +337,19 @@ function! ale#sign#SetSigns(buffer, loclist) abort
     \   l:sign_map,
     \)
 
+    " Change the sign column color if the option is on.
+    if g:ale_change_sign_column_color && !empty(a:loclist)
+        highlight clear SignColumn
+        highlight link SignColumn ALESignColumnWithErrors
+    endif
+
     for l:command in l:command_list
         silent! execute l:command
     endfor
+
+    " Reset the sign column color when there are no more errors.
+    if g:ale_change_sign_column_color && empty(a:loclist)
+        highlight clear SignColumn
+        highlight link SignColumn ALESignColumnWithoutErrors
+    endif
 endfunction

test/sign/test_sign_column_highlighting.vader

@@ -1,4 +1,6 @@
 Before:
+  Save g:ale_change_sign_column_color
+
   function! ParseHighlight(name) abort
     redir => l:output
       silent execute 'highlight ' . a:name
@@ -20,14 +22,34 @@ Before:
   let g:sign_highlight = ParseHighlight('SignColumn')
 
 After:
+  Restore
+
   delfunction ParseHighlight
   call SetHighlight('SignColumn', g:sign_highlight)
   delfunction SetHighlight
   unlet! g:sign_highlight
 
+  sign unplace *
+
+Execute(The SignColumn highlight shouldn't be changed if the option is off):
+  let g:ale_change_sign_column_color = 0
+  let b:sign_highlight = ParseHighlight('SignColumn')
+
+  call ale#sign#SetSigns(bufnr(''), [
+  \ {'bufnr': bufnr(''), 'lnum': 1, 'col': 1, 'type': 'W', 'text': 'x'},
+  \])
+  AssertEqual b:sign_highlight, ParseHighlight('SignColumn')
+
+  call ale#sign#SetSigns(bufnr(''), [])
+  AssertEqual b:sign_highlight, ParseHighlight('SignColumn')
+
 Execute(The SignColumn highlight should be set and reset):
-  call ale#sign#SetSignColumnHighlight(1)
+  let g:ale_change_sign_column_color = 1
+
+  call ale#sign#SetSigns(bufnr(''), [
+  \ {'bufnr': bufnr(''), 'lnum': 1, 'col': 1, 'type': 'W', 'text': 'x'},
+  \])
   AssertEqual 'links to ALESignColumnWithErrors', ParseHighlight('SignColumn')
 
-  call ale#sign#SetSignColumnHighlight(0)
+  call ale#sign#SetSigns(bufnr(''), [])
   AssertEqual 'links to ALESignColumnWithoutErrors', ParseHighlight('SignColumn')