569 support vim sign group and priority (#2786)

* Use sign-group only on supported vim versions.

The sign-group feature is only available in nvim 0.4.0 and vim 8.1.614.

* Add priority to ALE signs.

This allows users to set a priority to ALE signs to take precedence over
other plugin signs.

11 files changed, 180 insertions, 58 deletions

diff --git a/autoload/ale/sign.vim b/autoload/ale/sign.vim
index 829de118..79352f47 100644
--- a/autoload/ale/sign.vim
+++ b/autoload/ale/sign.vim
@@ -14,6 +14,7 @@ let g:ale_sign_style_error = get(g:, 'ale_sign_style_error', g:ale_sign_error)
 let g:ale_sign_warning = get(g:, 'ale_sign_warning', '--')
 let g:ale_sign_style_warning = get(g:, 'ale_sign_style_warning', g:ale_sign_warning)
 let g:ale_sign_info = get(g:, 'ale_sign_info', g:ale_sign_warning)
+let g:ale_sign_priority = get(g:, 'ale_sign_priority', 30)
 " This variable sets an offset which can be set for sign IDs.
 " This ID can be changed depending on what IDs are set for other plugins.
 " The dummy sign will use the ID exactly equal to the offset.
@@ -147,24 +148,57 @@ function! ale#sign#GetSignName(sublist) abort
     return 'ALEErrorSign'
 endfunction
 
+function! s:PriorityCmd() abort
+    if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        return ' priority=' . g:ale_sign_priority . ' '
+    else
+        return ''
+    endif
+endfunction
+
+function! s:GroupCmd() abort
+    if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        return ' group=ale '
+    else
+        return ' '
+    endif
+endfunction
+
 " Read sign data for a buffer to a list of lines.
 function! ale#sign#ReadSigns(buffer) abort
     redir => l:output
-        silent execute 'sign place buffer=' . a:buffer
+        silent execute 'sign place ' . s:GroupCmd() . s:PriorityCmd()
+        \ . ' buffer=' . a:buffer
     redir end
 
     return split(l:output, "\n")
 endfunction
 
+function! ale#sign#ParsePattern() abort
+    if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        " Matches output like :
+        " line=4  id=1  group=ale  name=ALEErrorSign
+        " строка=1  id=1000001  group=ale  имя=ALEErrorSign
+        " 行=1  識別子=1000001  group=ale  名前=ALEWarningSign
+        " línea=12 id=1000001 group=ale  nombre=ALEWarningSign
+        " riga=1 id=1000001  group=ale   nome=ALEWarningSign
+        let l:pattern = '\v^.*\=(\d+).*\=(\d+).*group\=ale.*\=(ALE[a-zA-Z]+Sign)'
+    else
+        " Matches output like :
+        " line=4  id=1  name=ALEErrorSign
+        " строка=1  id=1000001  имя=ALEErrorSign
+        " 行=1  識別子=1000001  名前=ALEWarningSign
+        " línea=12 id=1000001 nombre=ALEWarningSign
+        " riga=1 id=1000001  nome=ALEWarningSign
+        let l:pattern = '\v^.*\=(\d+).*\=(\d+).*\=(ALE[a-zA-Z]+Sign)'
+    endif
+
+    return l:pattern
+endfunction
+
 " Given a list of lines for sign output, return a List of [line, id, group]
 function! ale#sign#ParseSigns(line_list) abort
-    " Matches output like :
-    " line=4  id=1  name=ALEErrorSign
-    " строка=1  id=1000001  имя=ALEErrorSign
-    " 行=1  識別子=1000001  名前=ALEWarningSign
-    " línea=12 id=1000001 nombre=ALEWarningSign
-    " riga=1 id=1000001, nome=ALEWarningSign
-    let l:pattern = '\v^.*\=(\d+).*\=(\d+).*\=(ALE[a-zA-Z]+Sign)'
+    let l:pattern =ale#sign#ParsePattern()
     let l:result = []
     let l:is_dummy_sign_set = 0
 
@@ -319,8 +353,10 @@ function! ale#sign#GetSignCommands(buffer, was_sign_set, sign_map) abort
     if !l:is_dummy_sign_set && (!empty(a:sign_map) || g:ale_sign_column_always)
         call add(l:command_list, 'sign place '
         \   .  g:ale_sign_offset
-        \   . ' line=1 name=ALEDummySign buffer='
-        \   . a:buffer
+        \   . s:GroupCmd()
+        \   . s:PriorityCmd()
+        \   . ' line=1 name=ALEDummySign '
+        \   . ' buffer=' . a:buffer
         \)
         let l:is_dummy_sign_set = 1
     endif
@@ -337,6 +373,8 @@ function! ale#sign#GetSignCommands(buffer, was_sign_set, sign_map) abort
             if index(l:info.current_id_list, l:info.new_id) < 0
                 call add(l:command_list, 'sign place '
                 \   . (l:info.new_id)
+                \   . s:GroupCmd()
+                \   . s:PriorityCmd()
                 \   . ' line=' . l:line_str
                 \   . ' name=' . (l:info.new_name)
                 \   . ' buffer=' . a:buffer
@@ -351,6 +389,7 @@ function! ale#sign#GetSignCommands(buffer, was_sign_set, sign_map) abort
             if l:current_id isnot l:info.new_id
                 call add(l:command_list, 'sign unplace '
                 \   . l:current_id
+                \   . s:GroupCmd()
                 \   . ' buffer=' . a:buffer
                 \)
             endif
@@ -361,6 +400,7 @@ function! ale#sign#GetSignCommands(buffer, was_sign_set, sign_map) abort
     if l:is_dummy_sign_set && !g:ale_sign_column_always
         call add(l:command_list, 'sign unplace '
         \   . g:ale_sign_offset
+        \   . s:GroupCmd()
         \   . ' buffer=' . a:buffer
         \)
     endif
@@ -415,3 +455,12 @@ function! ale#sign#SetSigns(buffer, loclist) abort
         highlight link SignColumn ALESignColumnWithoutErrors
     endif
 endfunction
+
+" Remove all signs.
+function! ale#sign#Clear() abort
+    if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        sign unplace group=ale *
+    else
+        sign unplace *
+    endif
+endfunction
diff --git a/doc/ale.txt b/doc/ale.txt
index e7ffba36..b368afd3 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -1543,6 +1543,16 @@ g:ale_set_signs                                               *g:ale_set_signs*
   To limit the number of signs ALE will set, see |g:ale_max_signs|.
 
 
+g:ale_sign_priority                                       *g:ale_sign_priority*
+
+  Type: |Number|
+  Default: `30`
+
+  From Neovim 0.4.0 and Vim 8.1, ALE can set sign priority to all signs. The
+  larger this value is, the higher priority ALE signs have over other plugin
+  signs. See |sign-priority| for further details on how priority works.
+
+
 g:ale_shell                                                       *g:ale_shell*
 
   Type: |String|
diff --git a/test/sign/test_linting_sets_signs.vader b/test/sign/test_linting_sets_signs.vader
index a8d5761f..bb042679 100644
--- a/test/sign/test_linting_sets_signs.vader
+++ b/test/sign/test_linting_sets_signs.vader
@@ -21,7 +21,7 @@ Before:
   let g:ale_set_highlights = 0
   let g:ale_echo_cursor = 0
 
-  sign unplace *
+  call ale#sign#Clear()
 
   function! TestCallback(buffer, output)
     return [
@@ -32,16 +32,20 @@ Before:
 
   function! CollectSigns()
     redir => l:output
-       silent exec 'sign place'
+      if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        silent exec 'sign place group=ale'
+      else
+        silent exec 'sign place'
+      endif
     redir END
 
     let l:actual_sign_list = []
 
     for l:line in split(l:output, "\n")
-      let l:match = matchlist(l:line, '\v^.*\=(\d+).*\=\d+.*\=(ALE[a-zA-Z]+Sign)')
+      let l:match = matchlist(l:line, ale#sign#ParsePattern())
 
       if len(l:match) > 0
-        call add(l:actual_sign_list, [l:match[1], l:match[2]])
+        call add(l:actual_sign_list, [l:match[1], l:match[3]])
       endif
     endfor
 
@@ -60,7 +64,7 @@ After:
   delfunction CollectSigns
 
   unlet! g:ale_run_synchronously_callbacks
-  sign unplace *
+  call ale#sign#Clear()
   call ale#linter#Reset()
 
 Execute(The signs should be updated after linting is done):
diff --git a/test/sign/test_sign_column_highlighting.vader b/test/sign/test_sign_column_highlighting.vader
index 0b506fa7..7ea5eb0f 100644
--- a/test/sign/test_sign_column_highlighting.vader
+++ b/test/sign/test_sign_column_highlighting.vader
@@ -30,7 +30,7 @@ After:
   delfunction SetHighlight
   unlet! g:sign_highlight
 
-  sign unplace *
+  call ale#sign#Clear()
 
 Execute(The SignColumn highlight shouldn't be changed if the option is off):
   let g:ale_change_sign_column_color = 0
diff --git a/test/sign/test_sign_limits.vader b/test/sign/test_sign_limits.vader
index b8868aeb..d7a4e2f5 100644
--- a/test/sign/test_sign_limits.vader
+++ b/test/sign/test_sign_limits.vader
@@ -30,7 +30,7 @@ After:
 
   delfunction SetNProblems
 
-  sign unplace *
+  call ale#sign#Clear()
 
 Execute(There should be no limit on signs with negative numbers):
   AssertEqual range(1, 42), SetNProblems(42)
diff --git a/test/sign/test_sign_parsing.vader b/test/sign/test_sign_parsing.vader
index 07848afb..de2a3e8c 100644
--- a/test/sign/test_sign_parsing.vader
+++ b/test/sign/test_sign_parsing.vader
@@ -1,35 +1,77 @@
 Execute (Parsing English signs should work):
-  AssertEqual
-  \ [0, [[9, 1000001, 'ALEWarningSign']]],
-  \ ale#sign#ParseSigns([
-  \   'Signs for app.js:',
-  \   '    line=9  id=1000001  name=ALEWarningSign',
-  \ ])
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [0, [[9, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns([
+    \   'Signs for app.js:',
+    \   '    line=9  id=1000001  group=ale  name=ALEWarningSign',
+    \ ])
+  else
+    AssertEqual
+    \ [0, [[9, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns([
+    \   'Signs for app.js:',
+    \   '    line=9  id=1000001  name=ALEWarningSign',
+    \ ])
+  endif
 
 Execute (Parsing Russian signs should work):
-  AssertEqual
-  \ [0, [[1, 1000001, 'ALEErrorSign']]],
-  \ ale#sign#ParseSigns(['    строка=1  id=1000001  имя=ALEErrorSign'])
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEErrorSign']]],
+    \ ale#sign#ParseSigns(['    строка=1  id=1000001  group=ale  имя=ALEErrorSign'])
+  else
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEErrorSign']]],
+    \ ale#sign#ParseSigns(['    строка=1  id=1000001  имя=ALEErrorSign'])
+  endif
 
 Execute (Parsing Japanese signs should work):
-  AssertEqual
-  \ [0, [[1, 1000001, 'ALEWarningSign']]],
-  \ ale#sign#ParseSigns(['    行=1  識別子=1000001  名前=ALEWarningSign'])
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    行=1  識別子=1000001  group=ale  名前=ALEWarningSign'])
+  else
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    行=1  識別子=1000001  名前=ALEWarningSign'])
+  endif
 
 Execute (Parsing Spanish signs should work):
-  AssertEqual
-  \ [0, [[12, 1000001, 'ALEWarningSign']]],
-  \ ale#sign#ParseSigns(['    línea=12 id=1000001 nombre=ALEWarningSign'])
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [0, [[12, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    línea=12 id=1000001  group=ale  nombre=ALEWarningSign'])
+  else
+    AssertEqual
+    \ [0, [[12, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    línea=12 id=1000001  nombre=ALEWarningSign'])
+  endif
 
 Execute (Parsing Italian signs should work):
-  AssertEqual
-  \ [0, [[1, 1000001, 'ALEWarningSign']]],
-  \ ale#sign#ParseSigns(['    riga=1 id=1000001, nome=ALEWarningSign'])
-  \
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    riga=1 id=1000001, group=ale  nome=ALEWarningSign'])
+  else
+    AssertEqual
+    \ [0, [[1, 1000001, 'ALEWarningSign']]],
+    \ ale#sign#ParseSigns(['    riga=1 id=1000001, nome=ALEWarningSign'])
+  endif
+
 Execute (The sign parser should indicate if the dummy sign is set):
-  AssertEqual
-  \ [1, [[1, 1000001, 'ALEErrorSign']]],
-  \ ale#sign#ParseSigns([
-  \   '    строка=1  id=1000001  имя=ALEErrorSign',
-  \   '    line=1  id=1000000  name=ALEDummySign',
-  \ ])
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    AssertEqual
+    \ [1, [[1, 1000001, 'ALEErrorSign']]],
+    \ ale#sign#ParseSigns([
+    \   '    строка=1  id=1000001  group=ale  имя=ALEErrorSign',
+    \   '    line=1  id=1000000  group=ale  name=ALEDummySign',
+    \ ])
+  else
+    AssertEqual
+    \ [1, [[1, 1000001, 'ALEErrorSign']]],
+    \ ale#sign#ParseSigns([
+    \   '    строка=1  id=1000001  имя=ALEErrorSign',
+    \   '    line=1  id=1000000  name=ALEDummySign',
+    \ ])
+  endif
diff --git a/test/sign/test_sign_placement.vader b/test/sign/test_sign_placement.vader
index f0b3ba2f..97bd9302 100644
--- a/test/sign/test_sign_placement.vader
+++ b/test/sign/test_sign_placement.vader
@@ -17,7 +17,7 @@ Before:
   let g:ale_echo_cursor = 0
 
   call ale#linter#Reset()
-  sign unplace *
+  call ale#sign#Clear()
 
   function! GenerateResults(buffer, output)
     return [
@@ -68,12 +68,16 @@ Before:
 
   function! ParseSigns()
     redir => l:output
-      silent sign place
+      if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+        silent sign place group=ale
+      else
+        silent sign place
+      endif
     redir END
 
     return map(
     \ split(l:output, '\n')[2:],
-    \ 'matchlist(v:val, ''^.*=\(\d\+\).*=\(\d\+\).*=\(.*\)$'')[1:3]',
+    \ 'matchlist(v:val, ''' . ale#sign#ParsePattern() . ''')[1:3]',
     \)
   endfunction
 
@@ -92,7 +96,7 @@ After:
   delfunction GenerateResults
   delfunction ParseSigns
   call ale#linter#Reset()
-  sign unplace *
+  call ale#sign#Clear()
 
 Execute(ale#sign#GetSignName should return the right sign names):
   AssertEqual 'ALEErrorSign', ale#sign#GetSignName([{'type': 'E'}])
@@ -148,9 +152,15 @@ Execute(The current signs should be set for running a job):
   \ ParseSigns()
 
 Execute(Loclist items with sign_id values should be kept):
-  exec 'sign place 1000347 line=3 name=ALEErrorSign buffer=' . bufnr('')
-  exec 'sign place 1000348 line=15 name=ALEErrorSign buffer=' . bufnr('')
-  exec 'sign place 1000349 line=16 name=ALEWarningSign buffer=' . bufnr('')
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    exec 'sign place 1000347 group=ale line=3 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000348 group=ale line=15 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000349 group=ale line=16 name=ALEWarningSign buffer=' . bufnr('')
+  else
+    exec 'sign place 1000347 line=3 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000348 line=15 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000349 line=16 name=ALEWarningSign buffer=' . bufnr('')
+  endif
 
   let g:loclist = [
   \ {'bufnr': bufnr(''), 'lnum': 1, 'col': 1, 'type': 'E', 'text': 'a', 'sign_id': 1000348},
@@ -287,10 +297,17 @@ Execute(No exceptions should be thrown when setting signs for invalid buffers):
 Execute(Signs should be removed when lines have multiple sign IDs on them):
   " We can fail to remove signs if there are multiple signs on one line,
   " say after deleting lines in Vim, etc.
-  exec 'sign place 1000347 line=3 name=ALEErrorSign buffer=' . bufnr('')
-  exec 'sign place 1000348 line=3 name=ALEWarningSign buffer=' . bufnr('')
-  exec 'sign place 1000349 line=10 name=ALEErrorSign buffer=' . bufnr('')
-  exec 'sign place 1000350 line=10 name=ALEWarningSign buffer=' . bufnr('')
+  if has('nvim-0.4.0') || (v:version >= 801 && has('patch614'))
+    exec 'sign place 1000347 group=ale line=3 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000348 group=ale line=3 name=ALEWarningSign buffer=' . bufnr('')
+    exec 'sign place 1000349 group=ale line=10 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000350 group=ale line=10 name=ALEWarningSign buffer=' . bufnr('')
+  else
+    exec 'sign place 1000347 line=3 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000348 line=3 name=ALEWarningSign buffer=' . bufnr('')
+    exec 'sign place 1000349 line=10 name=ALEErrorSign buffer=' . bufnr('')
+    exec 'sign place 1000350 line=10 name=ALEWarningSign buffer=' . bufnr('')
+  endif
 
   call ale#sign#SetSigns(bufnr(''), [])
   AssertEqual [], ParseSigns()
diff --git a/test/test_ale_toggle.vader b/test/test_ale_toggle.vader
index a0763cb1..1debcee6 100644
--- a/test/test_ale_toggle.vader
+++ b/test/test_ale_toggle.vader
@@ -82,7 +82,7 @@ Before:
   \ 'read_buffer': 0,
   \})
 
-  sign unplace *
+  call ale#sign#Clear()
 
 After:
   Restore
@@ -105,7 +105,7 @@ After:
   delfunction ParseAuGroups
 
   call setloclist(0, [])
-  sign unplace *
+  call ale#sign#Clear()
   call clearmatches()
 
 Given foobar (Some imaginary filetype):
diff --git a/test/test_highlight_placement.vader b/test/test_highlight_placement.vader
index c062018b..3b259655 100644
--- a/test/test_highlight_placement.vader
+++ b/test/test_highlight_placement.vader
@@ -114,7 +114,7 @@ After:
   delfunction GenerateResults
   call ale#linter#Reset()
   call clearmatches()
-  sign unplace *
+  call ale#sign#Clear()
   highlight clear SomeOtherGroup
 
   runtime autoload/ale/highlight.vim
diff --git a/test/test_results_not_cleared_when_opening_loclist.vader b/test/test_results_not_cleared_when_opening_loclist.vader
index 4a53d356..5621eb35 100644
--- a/test/test_results_not_cleared_when_opening_loclist.vader
+++ b/test/test_results_not_cleared_when_opening_loclist.vader
@@ -8,7 +8,7 @@ After:
 
   call setloclist(0, [])
   call clearmatches()
-  sign unplace *
+  call ale#sign#Clear()
 
 Given foobar (Some file):
   abc
diff --git a/test/test_setting_problems_found_in_previous_buffers.vader b/test/test_setting_problems_found_in_previous_buffers.vader
index 36eeb4ca..a5c8e0d3 100644
--- a/test/test_setting_problems_found_in_previous_buffers.vader
+++ b/test/test_setting_problems_found_in_previous_buffers.vader
@@ -38,7 +38,7 @@ After:
   " Items and markers, etc.
   call setloclist(0, [])
   call clearmatches()
-  sign unplace *
+  call ale#sign#Clear()
 
 Given foobar(A file with some lines):
   foo