#2492 - Try to fix a deoplete bug again

autoload/ale/completion.vim

@@ -549,6 +549,19 @@ function! s:OnReady(linter, lsp_details) abort
     endif
 endfunction
 
+" This function can be called to check if ALE can provide completion data for
+" the current buffer. 1 will be returned if there's a potential source of
+" completion data ALE can use, and 0 will be returned otherwise.
+function! ale#completion#CanProvideCompletions() abort
+    for l:linter in ale#linter#Get(&filetype)
+        if !empty(l:linter.lsp)
+            return 1
+        endif
+    endfor
+
+    return 0
+endfunction
+
 " This function can be used to manually trigger autocomplete, even when
 " g:ale_completion_enabled is set to false
 function! ale#completion#GetCompletions(source) abort

rplugin/python3/deoplete/sources/ale.py

@@ -30,6 +30,10 @@ def get_completion_position(self):
         return self.vim.call('ale#completion#GetCompletionPosition')
 
     def gather_candidates(self, context):
+        # Stop early if ALE can't provide completion data for this buffer.
+        if not self.vim.call('ale#completion#CanProvideCompletions'):
+            return None
+
         if context.get('is_refresh'):
             context['is_async'] = False
 
@@ -47,4 +51,4 @@ def gather_candidates(self, context):
             # Request some completion results.
             self.vim.call('ale#completion#GetCompletions', 'deoplete')
 
-        return None
+        return []

test/completion/test_public_completion_api.vader

@@ -0,0 +1,63 @@
+Before:
+  call ale#linter#Reset()
+
+  unlet! b:ale_linters
+  unlet! b:ale_completion_info
+  unlet! b:ale_completion_response
+  unlet! b:ale_completion_parser
+  unlet! b:ale_completion_result
+
+  function! Identity(x) abort
+    return a:x
+  endfunction
+
+After:
+  delfunction Identity
+
+  call ale#linter#Reset()
+
+  unlet! b:ale_linters
+  unlet! b:ale_completion_info
+  unlet! b:ale_completion_response
+  unlet! b:ale_completion_parser
+  unlet! b:ale_completion_result
+
+Execute(ale#completion#GetCompletionResult() should return v:null when there are no results):
+  AssertEqual v:null, ale#completion#GetCompletionResult()
+
+Execute(ale#completion#GetCompletionResult() should parse the result when it has yet to be parsed):
+  let b:ale_completion_response = [1]
+  let b:ale_completion_parser = 'Identity'
+
+  AssertEqual [1], ale#completion#GetCompletionResult()
+  Assert !exists('b:ale_completion_response')
+  Assert !exists('b:ale_completion_parser')
+  AssertEqual [1], b:ale_completion_result
+
+Execute(ale#completion#GetCompletionResult() should return a result computed previously):
+  let b:ale_completion_result = [1]
+
+  Assert !exists('b:ale_completion_response')
+  Assert !exists('b:ale_completion_parser')
+  AssertEqual [1], ale#completion#GetCompletionResult()
+
+Execute(ale#completion#GetCompletionPosition() should return 0 when there is no completion information):
+  AssertEqual 0, ale#completion#GetCompletionPosition()
+
+Given python(Some Python file):
+  foo bar
+
+Execute(ale#completion#GetCompletionPosition() should return the position in the file when information is available):
+  let b:ale_completion_info = {'line': 1, 'column': 6}
+
+  " This is the first character of 'bar'
+  AssertEqual 4, ale#completion#GetCompletionPosition()
+
+Execute(ale#completion#CanProvideCompletions should return 0 when no completion sources are available):
+  AssertEqual 0, ale#completion#CanProvideCompletions()
+
+Execute(ale#completion#CanProvideCompletions should return 1 when at least one completion source is available):
+  runtime ale_linters/python/pyls.vim
+  let b:ale_linters = ['pyls']
+
+  AssertEqual 1, ale#completion#CanProvideCompletions()

test/python/test_deoplete_source.py

@@ -23,7 +23,7 @@ def setUp(self):
         super(DeopleteSourceTest, self).setUp()
 
         self.call_list = []
-        self.call_results = {}
+        self.call_results = {'ale#completion#CanProvideCompletions': 1}
         self.source = ale_module.Source('vim')
         self.source.vim = VimMock(self.call_list, self.call_results)
 
@@ -59,37 +59,52 @@ def test_completion_position(self):
     def test_request_completion_results(self):
         context = {'is_async': False}
 
-        self.assertIsNone(self.source.gather_candidates(context))
+        self.assertEqual(self.source.gather_candidates(context), [])
         self.assertEqual(context, {'is_async': True})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletions', ('deoplete',)),
         ])
 
+    def test_request_completion_results_from_buffer_without_providers(self):
+        self.call_results['ale#completion#CanProvideCompletions'] = 0
+        context = {'is_async': False}
+
+        self.assertIsNone(self.source.gather_candidates(context), [])
+        self.assertEqual(context, {'is_async': False})
+        self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
+        ])
+
     def test_refresh_completion_results(self):
         context = {'is_async': False}
 
-        self.assertIsNone(self.source.gather_candidates(context))
+        self.assertEqual(self.source.gather_candidates(context), [])
         self.assertEqual(context, {'is_async': True})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletions', ('deoplete',)),
         ])
 
         context = {'is_async': True, 'is_refresh': True}
 
-        self.assertIsNone(self.source.gather_candidates(context))
+        self.assertEqual(self.source.gather_candidates(context), [])
         self.assertEqual(context, {'is_async': True, 'is_refresh': True})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletions', ('deoplete',)),
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletions', ('deoplete',)),
         ])
 
     def test_poll_no_result(self):
         context = {'is_async': True}
         self.call_results['ale#completion#GetCompletionResult'] = None
 
-        self.assertIsNone(self.source.gather_candidates(context))
+        self.assertEqual(self.source.gather_candidates(context), [])
         self.assertEqual(context, {'is_async': True})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletionResult', ()),
         ])
 
@@ -100,6 +115,7 @@ def test_poll_empty_result_ready(self):
         self.assertEqual(self.source.gather_candidates(context), [])
         self.assertEqual(context, {'is_async': False})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletionResult', ()),
         ])
 
@@ -126,5 +142,6 @@ def test_poll_non_empty_result_ready(self):
         ])
         self.assertEqual(context, {'is_async': False})
         self.assertEqual(self.call_list, [
+            ('ale#completion#CanProvideCompletions', ()),
             ('ale#completion#GetCompletionResult', ()),
         ])