Fix issues with switching buffers rapidly causing errors by remembering the buffer and passing the buffer value to various functions.

ale_linters/javascript/eslint.vim

@@ -4,7 +4,7 @@ endif
 
 let g:loaded_ale_linters_javascript_eslint = 1
 
-function! ale_linters#javascript#eslint#Handle(lines)
+function! ale_linters#javascript#eslint#Handle(buffer, lines)
     " Matches patterns line the following:
     "
     " <text>:47:14: Missing trailing comma. [Warning/comma-dangle]
@@ -29,7 +29,7 @@ function! ale_linters#javascript#eslint#Handle(lines)
 
         " vcol is Needed to indicate that the column is a character.
         call add(output, {
-        \   'bufnr': bufnr('%'),
+        \   'bufnr': a:buffer,
         \   'lnum': l:match[1] + 0,
         \   'vcol': 0,
         \   'col': l:match[2] + 0,

ale_linters/python/flake8.vim

@@ -4,7 +4,7 @@ endif
 
 let g:loaded_ale_linters_python_flake8 = 1
 
-function! ale_linters#python#flake8#Handle(lines)
+function! ale_linters#python#flake8#Handle(buffer, lines)
     " Matches patterns line the following:
     "
     " stdin:6:6: E111 indentation is not a multiple of four
@@ -26,7 +26,7 @@ function! ale_linters#python#flake8#Handle(lines)
 
         " vcol is Needed to indicate that the column is a character.
         call add(output, {
-        \   'bufnr': bufnr('%'),
+        \   'bufnr': a:buffer,
         \   'lnum': line,
         \   'vcol': 0,
         \   'col': column,

plugin/ale/cursor.vim

@@ -53,16 +53,20 @@ function! ale#cursor#TruncatedEcho(message)
 endfunction
 
 function! ale#cursor#EchoCursorWarning()
-    if !exists('b:ale_loclist')
+    let buffer = bufnr('%')
+
+    if !has_key(g:ale_buffer_loclist_map, buffer)
         return
     endif
 
+    let loclist = g:ale_buffer_loclist_map[buffer]
+
     let pos = getcurpos()
 
-    let index = s:BinarySearch(b:ale_loclist, pos[1], pos[2])
+    let index = s:BinarySearch(loclist, pos[1], pos[2])
 
     if index >= 0
-        call ale#cursor#TruncatedEcho(b:ale_loclist[index]['text'])
+        call ale#cursor#TruncatedEcho(loclist[index]['text'])
     else
         echo
     endif

plugin/ale/sign.vim

@@ -25,10 +25,8 @@ sign define ALEErrorSign text=>> texthl=ALEErrorSign
 sign define ALEWarningSign text=-- texthl=ALEWarningSign
 
 " This function will set the signs which show up on the left.
-function! ale#sign#SetSigns(loclist)
-    let buffer = bufnr('%')
-
-    exec 'sign unplace * buffer=' . buffer
+function! ale#sign#SetSigns(buffer, loclist)
+    exec 'sign unplace * buffer=' . a:buffer
 
     let signlist = []
 
@@ -59,7 +57,7 @@ function! ale#sign#SetSigns(loclist)
         let sign_line = 'sign place ' . (i + 1)
             \. ' line=' . obj['lnum']
             \. ' name=' . name
-            \. ' buffer=' . buffer
+            \. ' buffer=' . a:buffer
 
         exec sign_line
     endfor

plugin/ale/zmain.vim

@@ -1,7 +1,3 @@
-" Always set buffer variables for each buffer
-let b:ale_should_reset_loclist = 0
-let b:ale_loclist = []
-
 if exists('g:loaded_ale_zmain')
     finish
 endif
@@ -10,9 +6,22 @@ let g:loaded_ale_zmain = 1
 
 let s:lint_timer = -1
 let s:linters = {}
+
+" Stores information for each job including:
+"
+" linter: The linter dictionary for the job.
+" buffer: The buffer number for the job.
+" output: The array of lines for the ouptut of the job.
+let s:job_info_map = {}
+
 let s:job_linter_map = {}
+let s:job_buffer_map = {}
 let s:job_output_map = {}
 
+" Globals which each part of the plugin should use.
+let g:ale_buffer_loclist_map = {}
+let g:ale_buffer_should_reset_map = {}
+
 function! s:GetFunction(string_or_ref)
     if type(a:string_or_ref) == type('')
         return function(a:string_or_ref)
@@ -22,7 +31,7 @@ function! s:GetFunction(string_or_ref)
 endfunction
 
 function! s:ClearJob(job)
-    let linter = s:job_linter_map[a:job]
+    let linter = s:job_info_map[a:job].linter
 
     if has('nvim')
         call jobstop(a:job)
@@ -30,17 +39,16 @@ function! s:ClearJob(job)
         call job_stop(a:job)
     endif
 
-    call remove(s:job_output_map, a:job)
-    call remove(s:job_linter_map, a:job)
+    call remove(s:job_info_map, a:job)
     call remove(linter, 'job')
 endfunction
 
 function! s:GatherOutput(job, data)
-    if !has_key(s:job_output_map, a:job)
+    if !has_key(s:job_info_map, a:job)
         return
     endif
 
-    call extend(s:job_output_map[a:job], a:data)
+    call extend(s:job_info_map[a:job].output, a:data)
 endfunction
 
 function! s:GatherOutputNeoVim(job, data, event)
@@ -72,36 +80,39 @@ function! s:LocItemCompare(left, right)
 endfunction
 
 function! s:HandleExit(job)
-    if !has_key(s:job_linter_map, a:job)
+    if !has_key(s:job_info_map, a:job)
         return
     endif
 
-    let linter = s:job_linter_map[a:job]
-    let output = s:job_output_map[a:job]
+    let job_info = s:job_info_map[a:job]
 
     call s:ClearJob(a:job)
 
-    let linter_loclist = s:GetFunction(linter.callback)(output)
+    let linter = job_info.linter
+    let output = job_info.output
+    let buffer = job_info.buffer
 
-    if b:ale_should_reset_loclist
-        let b:ale_should_reset_loclist = 0
-        let b:ale_loclist = []
+    let linter_loclist = s:GetFunction(linter.callback)(buffer, output)
+
+    if g:ale_buffer_should_reset_map[buffer]
+        let g:ale_buffer_should_reset_map[buffer] = 0
+        let g:ale_buffer_loclist_map[buffer] = []
     endif
 
     " Add the loclist items from the linter.
-    call extend(b:ale_loclist, linter_loclist)
+    call extend(g:ale_buffer_loclist_map[buffer], linter_loclist)
 
     " Sort the loclist again.
     " We need a sorted list so we can run a binary search against it
     " for efficient lookup of the messages in the cursor handler.
-    call sort(b:ale_loclist, 's:LocItemCompare')
+    call sort(g:ale_buffer_loclist_map[buffer], 's:LocItemCompare')
 
     if g:ale_set_loclist
-        call setloclist(0, b:ale_loclist)
+        call setloclist(0, g:ale_buffer_loclist_map[buffer])
     endif
 
     if g:ale_set_signs
-        call ale#sign#SetSigns(b:ale_loclist)
+        call ale#sign#SetSigns(buffer, g:ale_buffer_loclist_map[buffer])
     endif
 
     " Mark line 200, column 17 with a squiggly line or something
@@ -116,17 +127,15 @@ function! s:HandleExitVim(channel)
     call s:HandleExit(ch_getjob(a:channel))
 endfunction
 
-function! s:ApplyLinter(linter)
+function! s:ApplyLinter(buffer, linter)
     if has_key(a:linter, 'job')
         " Stop previous jobs for the same linter.
         call s:ClearJob(a:linter.job)
     endif
 
-    let buffer = bufnr('%')
-
     if has_key(a:linter, 'command_callback')
         " If there is a callback for generating a command, call that instead.
-        let command = s:GetFunction(a:linter.command_callback)(buffer)
+        let command = s:GetFunction(a:linter.command_callback)(a:buffer)
     else
         let command = a:linter.command
     endif
@@ -144,14 +153,17 @@ function! s:ApplyLinter(linter)
         \   'out_cb': function('s:GatherOutputVim'),
         \   'close_cb': function('s:HandleExitVim'),
         \   'in_io': 'buffer',
-        \   'in_buf': buffer,
+        \   'in_buf': a:buffer,
         \})
 
         call ch_close_in(job_getchannel(a:linter.job))
     endif
 
-    let s:job_linter_map[a:linter.job] = a:linter
-    let s:job_output_map[a:linter.job] = []
+    let s:job_info_map[a:linter.job] = {
+    \   'linter': a:linter,
+    \   'buffer': a:buffer,
+    \   'output': [],
+    \}
 
     if has('nvim')
         " For NeoVim, we have to send the text in the buffer to the command.
@@ -164,14 +176,26 @@ function! s:TimerHandler(...)
     let filetype = &filetype
     let linters = ALEGetLinters(filetype)
 
+    let buffer = bufnr('%')
+
     " Set a variable telling us to clear the loclist later.
-    let b:ale_should_reset_loclist = 1
+    let g:ale_buffer_should_reset_map[buffer] = 1
 
     for linter in linters
-        call s:ApplyLinter(linter)
+        call s:ApplyLinter(buffer, linter)
     endfor
 endfunction
 
+function s:BufferCleanup(buffer)
+    if has_key(g:ale_buffer_should_reset_map, a:buffer)
+        call remove(g:ale_buffer_should_reset_map, a:buffer)
+    endif
+
+    if has_key(g:ale_buffer_loclist_map, a:buffer)
+        call remove(g:ale_buffer_loclist_map, a:buffer)
+    endif
+endfunction
+
 function! ALEAddLinter(filetype, linter)
     " Check if the linter program is executable before adding it.
     if !executable(a:linter.executable)
@@ -244,3 +268,9 @@ if g:ale_lint_on_enter
         autocmd BufEnter * call ALELint(0)
     augroup END
 endif
+
+" Clean up buffers automatically when they are unloaded.
+augroup ALEBuffferCleanup
+    autocmd!
+    autocmd BufUnload * call s:BufferCleanup('<abuf>')
+augroup END