LSP configuration via didChangeConfiguration (#1852)

* adding LSP configuration via workspace/didChangeConfiguration

autoload/ale/linter.vim

@@ -255,6 +255,14 @@ function! ale#linter#PreProcess(filetype, linter) abort
         elseif has_key(a:linter, 'initialization_options')
             let l:obj.initialization_options = a:linter.initialization_options
         endif
+
+        if has_key(a:linter, 'lsp_config')
+            if type(a:linter.lsp_config) isnot v:t_dict
+                throw '`lsp_config` must be a Dictionary'
+            endif
+
+            let l:obj.lsp_config = a:linter.lsp_config
+        endif
     endif
 
     let l:obj.output_stream = get(a:linter, 'output_stream', 'stdout')

autoload/ale/lsp/message.vim

@@ -138,3 +138,9 @@ function! ale#lsp#message#Hover(buffer, line, column) abort
     \   'position': {'line': a:line - 1, 'character': a:column},
     \}]
 endfunction
+
+function! ale#lsp#message#DidChangeConfiguration(buffer, config) abort
+    return [0, 'workspace/didChangeConfiguration', {
+    \   'settings': a:config,
+    \}]
+endfunction

autoload/ale/lsp_linter.vim

@@ -190,6 +190,12 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
 
     let l:language_id = ale#util#GetFunction(a:linter.language_callback)(a:buffer)
 
+    if !empty(get(a:linter, 'lsp_config'))
+        " set LSP configuration options (workspace/didChangeConfiguration)
+        let l:config_message = ale#lsp#message#DidChangeConfiguration(a:buffer, a:linter.lsp_config)
+        call ale#lsp#Send(l:conn_id, l:config_message)
+    endif
+
     let l:details = {
     \   'buffer': a:buffer,
     \   'connection_id': l:conn_id,

test/lsp/test_lsp_client_messages.vader

@@ -175,6 +175,22 @@ Execute(ale#lsp#message#Hover() should return correct messages):
   \ ],
   \ ale#lsp#message#Hover(bufnr(''), 12, 34)
 
+Execute(ale#lsp#message#DidChangeConfiguration() should return correct messages):
+  let g:ale_lsp_configuration = {
+  \ 'foo': 'bar'
+  \ }
+  AssertEqual
+  \ [
+  \   0,
+  \   'workspace/didChangeConfiguration',
+  \   {
+  \     'settings': {
+  \         'foo': 'bar',
+  \     }
+  \   }
+  \ ],
+  \ ale#lsp#message#DidChangeConfiguration(bufnr(''), g:ale_lsp_configuration)
+
 Execute(ale#lsp#tsserver_message#Open() should return correct messages):
   AssertEqual
   \ [

test/test_linter_defintion_processing.vader

@@ -490,7 +490,7 @@ Execute(PreProcess should complain about using initialization_options and initia
   AssertThrows call ale#linter#PreProcess('testft', g:linter)
   AssertEqual 'Only one of `initialization_options` or `initialization_options_callback` should be set', g:vader_exception
 
-Execute (PreProcess should throw when initialization_options_callback is not a callback):
+Execute(PreProcess should throw when initialization_options_callback is not a callback):
   AssertThrows call ale#linter#PreProcess('testft', {
   \ 'name': 'foo',
   \ 'lsp': 'socket',
@@ -500,3 +500,32 @@ Execute (PreProcess should throw when initialization_options_callback is not a c
   \ 'initialization_options_callback': {},
   \})
   AssertEqual '`initialization_options_callback` must be a callback if defined', g:vader_exception
+
+Execute(PreProcess should accept LSP configuration options via lsp_config):
+  let g:ale_lsp_configuration = {
+  \ 'foo': 'bar'
+  \}
+
+  let g:linter = {
+  \ 'name': 'x',
+  \ 'lsp': 'socket',
+  \ 'address_callback': 'X',
+  \ 'language_callback': 'x',
+  \ 'project_root_callback': 'x',
+  \ 'lsp_config': g:ale_lsp_configuration,
+  \}
+
+  AssertEqual {'foo': 'bar'}, ale#linter#PreProcess('testft', g:linter).lsp_config
+
+
+Execute(PreProcess should throw when lsp_config is not a Dictionary):
+  AssertThrows call ale#linter#PreProcess('testft', {
+  \ 'name': 'foo',
+  \ 'lsp': 'socket',
+  \ 'address_callback': 'X',
+  \ 'language': 'x',
+  \ 'project_root_callback': 'x',
+  \ 'lsp_config': 'x',
+  \})
+  AssertEqual '`lsp_config` must be a Dictionary', g:vader_exception
+