Fix #4413 - Avoid errors for invalid buffers in ale#virtualtext#Clear

autoload/ale/floating_preview.vim

@@ -52,9 +52,9 @@ function! s:NvimShow(lines, options) abort
         autocmd!
 
         if g:ale_close_preview_on_insert
-            autocmd CursorMoved,TabLeave,WinLeave,InsertEnter <buffer> ++once call s:NvimClose()
+            autocmd CursorMoved,TabLeave,WinLeave,BufWinLeave,WinScrolled,InsertEnter <buffer> ++once call s:NvimClose()
         else
-            autocmd CursorMoved,TabLeave,WinLeave <buffer> ++once call s:NvimClose()
+            autocmd CursorMoved,TabLeave,WinLeave,BufWinLeave,WinScrolled <buffer> ++once call s:NvimClose()
         endif
     augroup END
 

autoload/ale/highlight.vim

@@ -22,26 +22,6 @@ if !hlexists('ALEInfo')
     highlight link ALEInfo ALEWarning
 endif
 
-if !hlexists('ALEVirtualTextError')
-    highlight link ALEVirtualTextError ALEError
-endif
-
-if !hlexists('ALEVirtualTextStyleError')
-    highlight link ALEVirtualTextStyleError ALEVirtualTextError
-endif
-
-if !hlexists('ALEVirtualTextWarning')
-    highlight link ALEVirtualTextWarning ALEWarning
-endif
-
-if !hlexists('ALEVirtualTextStyleWarning')
-    highlight link ALEVirtualTextStyleWarning ALEVirtualTextWarning
-endif
-
-if !hlexists('ALEVirtualTextInfo')
-    highlight link ALEVirtualTextInfo ALEVirtualTextWarning
-endif
-
 " The maximum number of items for the second argument of matchaddpos()
 let s:MAX_POS_VALUES = 8
 let s:MAX_COL_SIZE = 1073741824 " pow(2, 30)

autoload/ale/virtualtext.vim

@@ -3,12 +3,36 @@ scriptencoding utf-8
 " Author: Luan Santos <cfcluan@gmail.com>
 " Description: Shows lint message for the current line as virtualtext, if any
 
+if !hlexists('ALEVirtualTextError')
+    highlight link ALEVirtualTextError SpellBad
+endif
+
+if !hlexists('ALEVirtualTextStyleError')
+    highlight link ALEVirtualTextStyleError ALEVirtualTextError
+endif
+
+if !hlexists('ALEVirtualTextWarning')
+    highlight link ALEVirtualTextWarning SpellCap
+endif
+
+if !hlexists('ALEVirtualTextStyleWarning')
+    highlight link ALEVirtualTextStyleWarning ALEVirtualTextWarning
+endif
+
+if !hlexists('ALEVirtualTextInfo')
+    highlight link ALEVirtualTextInfo ALEVirtualTextWarning
+endif
+
 " Controls the milliseconds delay before showing a message.
 let g:ale_virtualtext_delay = get(g:, 'ale_virtualtext_delay', 10)
-let s:cursor_timer = -1
-let s:last_pos = [0, 0, 0]
+let s:cursor_timer = get(s:, 'cursor_timer', -1)
+let s:last_pos = get(s:, 'last_pos', [0, 0, 0])
+let s:hl_list = get(s:, 'hl_list', [])
+
+if !has_key(s:, 'has_virt_text')
     let s:has_virt_text = 0
     let s:emulate_virt = 0
+    let s:last_virt = -1
 
     if has('nvim-0.3.2')
         let s:ns_id = nvim_create_namespace('ale')
@@ -16,16 +40,15 @@ if has('nvim-0.3.2')
     elseif has('textprop') && has('popupwin')
         let s:has_virt_text = 1
         let s:emulate_virt = !has('patch-9.0.0297')
-    let s:hl_list = []
 
         if s:emulate_virt
             call prop_type_add('ale', {})
-        let s:last_virt = -1
+        endif
     endif
 endif
 
 function! ale#virtualtext#Clear(buf) abort
-    if !s:has_virt_text
+    if !s:has_virt_text || !bufexists(str2nr(a:buf))
         return
     endif
 
@@ -50,14 +73,15 @@ function! ale#virtualtext#ShowMessage(message, hl_group, buf, line) abort
         return
     endif
 
+    let l:line = max([1, a:line])
     let l:prefix = get(g:, 'ale_virtualtext_prefix', '> ')
     let l:msg = l:prefix.trim(substitute(a:message, '\n', ' ', 'g'))
 
     if has('nvim')
-        call nvim_buf_set_virtual_text(a:buf, s:ns_id, a:line-1, [[l:msg, a:hl_group]], {})
+        call nvim_buf_set_virtual_text(a:buf, s:ns_id, l:line-1, [[l:msg, a:hl_group]], {})
     elseif s:emulate_virt
         let l:left_pad = col('$')
-        call prop_add(a:line, l:left_pad, {
+        call prop_add(l:line, l:left_pad, {
         \ 'type': 'ale',
         \})
         let s:last_virt = popup_create(l:msg, {
@@ -71,14 +95,19 @@ function! ale#virtualtext#ShowMessage(message, hl_group, buf, line) abort
         \ 'zindex': 2
         \})
     else
-        let type = prop_type_get(a:hl_group)
+        let l:type = prop_type_get(a:hl_group)
 
-        if type == {}
-            call add(s:hl_list, a:hl_group)
+        if l:type == {}
             call prop_type_add(a:hl_group, {'highlight': a:hl_group})
         endif
 
-        call prop_add(a:line, 0, {
+        " Add highlight groups to the list so we can clear them later.
+        if index(s:hl_list, a:hl_group) == -1
+            call add(s:hl_list, a:hl_group)
+        endif
+
+        " We ignore all errors from prop_add.
+        silent! call prop_add(l:line, 0, {
         \ 'type': a:hl_group,
         \ 'text': ' ' . l:msg,
         \ 'bufnr': a:buf
@@ -93,22 +122,24 @@ function! s:StopCursorTimer() abort
     endif
 endfunction
 
-function! ale#virtualtext#GetHlGroup(type, style) abort
+function! ale#virtualtext#GetHlGroup(type, sub_type) abort
     if a:type is# 'E'
-        if a:style is# 'style'
+        if a:sub_type is# 'style'
             return 'ALEVirtualTextStyleError'
-        else
+        endif
+
         return 'ALEVirtualTextError'
     endif
-    elseif a:type is# 'W'
-        if a:style is# 'style'
+
+    if a:type is# 'W'
+        if a:sub_type is# 'style'
             return 'ALEVirtualTextStyleWarning'
-        else
+        endif
+
         return 'ALEVirtualTextWarning'
     endif
-    else
+
     return 'ALEVirtualTextInfo'
-    endif
 endfunction
 
 function! ale#virtualtext#ShowCursorWarning(...) abort
@@ -181,7 +212,7 @@ function! ale#virtualtext#SetTexts(buf, loclist) abort
             continue
         endif
 
-        let hl = ale#virtualtext#GetHlGroup(l['type'], get(l, 'sub_type', ''))
-        call ale#virtualtext#ShowMessage(l['text'], hl, a:buf, l['lnum'])
+        let l:hl = ale#virtualtext#GetHlGroup(l['type'], get(l, 'sub_type', ''))
+        call ale#virtualtext#ShowMessage(l['text'], l:hl, a:buf, l['lnum'])
     endfor
 endfunction

doc/ale.txt

@@ -2508,7 +2508,7 @@ ALEStyleWarningSignLineNr                           *ALEStyleWarningSignLineNr*
 
 ALEVirtualTextError                                       *ALEVirtualTextError*
 
-  Default: `highlight link ALEVirtualTextError ALEError`
+  Default: `highlight link ALEVirtualTextError SpellBad`
 
   The highlight for virtualtext errors. See |g:ale_virtualtext_cursor|.
 
@@ -2536,7 +2536,7 @@ ALEVirtualTextStyleWarning                         *ALEVirtualTextStyleWarning*
 
 ALEVirtualTextWarning                                   *ALEVirtualTextWarning*
 
-  Default: `highlight link ALEVirtualTextWarning ALEWarning`
+  Default: `highlight link ALEVirtualTextWarning SpellCap`
 
   The highlight for virtualtext errors. See |g:ale_virtualtext_cursor|.