Fix #371 Allow ALE to be disabled in different buffers

autoload/ale.vim

@@ -29,6 +29,11 @@ function! ale#Queue(delay, ...) abort
         throw "linting_flag must be either '' or 'lint_file'"
     endif
 
+    " Stop here if ALE is disabled.
+    if !ale#Var(bufnr(''), 'enabled')
+        return
+    endif
+
     if ale#ShouldDoNothing()
         return
     endif

autoload/ale/cursor.vim

@@ -66,6 +66,15 @@ function! s:StopCursorTimer() abort
 endfunction
 
 function! ale#cursor#EchoCursorWarning(...) abort
+    " Stop here if ALE is disabled.
+    if !ale#Var(bufnr(''), 'enabled')
+        return
+    endif
+
+    if ale#ShouldDoNothing()
+        return
+    endif
+
     " Only echo the warnings in normal mode, otherwise we will get problems.
     if mode() !=# 'n'
         return
@@ -89,6 +98,11 @@ let s:cursor_timer = -1
 let s:last_pos = [0, 0, 0]
 
 function! ale#cursor#EchoCursorWarningWithDelay() abort
+    " Stop here if ALE is disabled.
+    if !ale#Var(bufnr(''), 'enabled')
+        return
+    endif
+
     if ale#ShouldDoNothing()
         return
     endif

doc/ale.txt

@@ -277,6 +277,7 @@ g:ale_emit_conflict_warnings                     *g:ale_emit_conflict_warnings*
 
 
 g:ale_enabled                                                   *g:ale_enabled*
+                                                                *b:ale_enabled*
 
   Type: |Number|
   Default: `1`
@@ -285,6 +286,16 @@ g:ale_enabled                                                   *g:ale_enabled*
   error checking will be performed, etc. ALE can be toggled on and off with
   the |ALEToggle| command, which changes this option.
 
+  ALE can be disabled in each buffer by setting `let b:ale_enabled = 0`
+  Disabling ALE based on filename patterns can be accomplished by setting
+  a regular expression for |g:ale_pattern_options|. For example: >
+
+  " Disable linting for all minified JS files.
+  let g:ale_pattern_options = {'\.min.js$': {'ale_enabled': 0}}
+<
+
+  See |g:ale_pattern_options| for more information on that option.
+
 
 g:ale_fixers                                                     *g:ale_fixers*
                                                                  *b:ale_fixers*

test/test_disabling_ale.vader

@@ -0,0 +1,92 @@
+Before:
+  Save g:ale_buffer_info, g:ale_enabled, b:ale_enabled
+
+  function! TestCallback(buffer, output)
+    return []
+  endfunction
+
+  call ale#linter#Define('foobar', {
+  \ 'name': 'testlinter',
+  \ 'callback': 'TestCallback',
+  \ 'executable': 'echo',
+  \ 'command': 'true',
+  \})
+
+  function GetLastMessage()
+    redir => l:output
+      silent mess
+    redir END
+
+    let l:lines = split(l:output, "\n")
+
+    return empty(l:lines) ? '' : l:lines[-1]
+  endfunction
+
+  echomsg ''
+
+After:
+  Restore
+  call ale#linter#Reset()
+  delfunction TestCallback
+  delfunction GetLastMessage
+
+Given foobar (Some imaginary filetype):
+  foo
+  bar
+  baz
+
+Execute(Linting shouldn't happen when ALE is disabled globally):
+  let g:ale_enabled = 0
+  let g:ale_buffer_info = {}
+
+  call ale#Queue(0)
+
+  AssertEqual {}, g:ale_buffer_info
+
+Execute(Linting shouldn't happen when ALE is disabled locally):
+  let b:ale_enabled = 0
+  let g:ale_buffer_info = {}
+
+  call ale#Queue(0)
+
+  AssertEqual {}, g:ale_buffer_info
+
+Execute(Cursor warnings shouldn't be echoed when ALE is disabled globally):
+  let g:ale_enabled = 0
+  let g:ale_buffer_info = {
+  \ bufnr('%'): {
+  \   'loclist': [
+  \     {
+  \       'lnum': 2,
+  \       'col': 10,
+  \       'linter_name': 'testlinter',
+  \       'type': 'W',
+  \       'text': 'X'
+  \     },
+  \   ],
+  \ },
+  \}
+
+  call cursor(2, 16)
+  call ale#cursor#EchoCursorWarning()
+  AssertEqual '', GetLastMessage()
+
+Execute(Cursor warnings shouldn't be echoed when ALE is disabled locally):
+  let b:ale_enabled = 0
+  let g:ale_buffer_info = {
+  \ bufnr('%'): {
+  \   'loclist': [
+  \     {
+  \       'lnum': 2,
+  \       'col': 10,
+  \       'linter_name': 'testlinter',
+  \       'type': 'W',
+  \       'text': 'X'
+  \     },
+  \   ],
+  \ },
+  \}
+
+  call cursor(2, 16)
+  call ale#cursor#EchoCursorWarning()
+  AssertEqual '', GetLastMessage()