Allow initialization options to be passed to language servers

autoload/ale/linter.vim

@@ -227,6 +227,21 @@ function! ale#linter#PreProcess(linter) abort
                 throw '`completion_filter` must be a callback'
             endif
         endif
+
+        if has_key(a:linter, 'initialization_options_callback')
+            if has_key(a:linter, 'initialization_options')
+                throw 'Only one of `initialization_options` or '
+                \   . '`initialization_options_callback` should be set'
+            endif
+
+            let l:obj.initialization_options_callback = a:linter.initialization_options_callback
+
+            if !s:IsCallback(l:obj.initialization_options_callback)
+                throw '`initialization_options_callback` must be a callback if defined'
+            endif
+        elseif has_key(a:linter, 'initialization_options')
+            let l:obj.initialization_options = a:linter.initialization_options
+        endif
     endif
 
     let l:obj.output_stream = get(a:linter, 'output_stream', 'stdout')
@@ -451,12 +466,20 @@ function! ale#linter#StartLSP(buffer, linter, callback) abort
         return {}
     endif
 
+    let l:initialization_options = {}
+    if has_key(a:linter, 'initialization_options_callback')
+        let l:initialization_options = ale#util#GetFunction(a:linter.initialization_options_callback)(a:buffer)
+    elseif has_key(a:linter, 'initialization_options')
+        let l:initialization_options = a:linter.initialization_options
+    endif
+
     if a:linter.lsp is# 'socket'
         let l:address = ale#linter#GetAddress(a:buffer, a:linter)
         let l:conn_id = ale#lsp#ConnectToAddress(
         \   l:address,
         \   l:root,
         \   a:callback,
+        \   l:initialization_options,
         \)
     else
         let l:executable = ale#linter#GetExecutable(a:buffer, a:linter)
@@ -474,6 +497,7 @@ function! ale#linter#StartLSP(buffer, linter, callback) abort
         \   l:command,
         \   l:root,
         \   a:callback,
+        \   l:initialization_options,
         \)
     endif
 

autoload/ale/lsp.vim

@@ -6,7 +6,7 @@
 let s:connections = []
 let g:ale_lsp_next_message_id = 1
 
-function! s:NewConnection() abort
+function! s:NewConnection(initialization_options) abort
     " id: The job ID as a Number, or the server address as a string.
     " data: The message data received so far.
     " executable: An executable only set for program connections.
@@ -18,6 +18,7 @@ function! s:NewConnection() abort
     \   'projects': {},
     \   'open_documents': [],
     \   'callback_list': [],
+    \   'initialization_options': a:initialization_options,
     \}
 
     call add(s:connections, l:conn)
@@ -271,7 +272,7 @@ endfunction
 "
 " The job ID will be returned for for the program if it ran, otherwise
 " 0 will be returned.
-function! ale#lsp#StartProgram(executable, command, project_root, callback) abort
+function! ale#lsp#StartProgram(executable, command, project_root, callback, initialization_options) abort
     if !executable(a:executable)
         return 0
     endif
@@ -279,7 +280,7 @@ function! ale#lsp#StartProgram(executable, command, project_root, callback) abor
     let l:conn = s:FindConnection('executable', a:executable)
 
     " Get the current connection or a new one.
-    let l:conn = !empty(l:conn) ? l:conn : s:NewConnection()
+    let l:conn = !empty(l:conn) ? l:conn : s:NewConnection(a:initialization_options)
     let l:conn.executable = a:executable
 
     if !has_key(l:conn, 'id') || !ale#job#IsRunning(l:conn.id)
@@ -305,10 +306,10 @@ function! ale#lsp#StartProgram(executable, command, project_root, callback) abor
 endfunction
 
 " Connect to an address and set up a callback for handling responses.
-function! ale#lsp#ConnectToAddress(address, project_root, callback) abort
+function! ale#lsp#ConnectToAddress(address, project_root, callback, initialization_options) abort
     let l:conn = s:FindConnection('id', a:address)
     " Get the current connection or a new one.
-    let l:conn = !empty(l:conn) ? l:conn : s:NewConnection()
+    let l:conn = !empty(l:conn) ? l:conn : s:NewConnection(a:initialization_options)
 
     if !has_key(l:conn, 'channel') || ch_status(l:conn.channel) isnot# 'open'
         let l:conn.channnel = ch_open(a:address, {
@@ -383,7 +384,7 @@ function! ale#lsp#Send(conn_id, message, ...) abort
         " Only send the init message once.
         if !l:project.init_request_id
             let [l:init_id, l:init_data] = ale#lsp#CreateMessageData(
-            \   ale#lsp#message#Initialize(l:project_root),
+            \   ale#lsp#message#Initialize(l:project_root, l:conn.initialization_options),
             \)
 
             let l:project.init_request_id = l:init_id

autoload/ale/lsp/message.vim

@@ -24,12 +24,13 @@ function! ale#lsp#message#GetNextVersionID() abort
     return l:id
 endfunction
 
-function! ale#lsp#message#Initialize(root_path) abort
+function! ale#lsp#message#Initialize(root_path, initialization_options) abort
     " TODO: Define needed capabilities.
     return [0, 'initialize', {
     \   'processId': getpid(),
     \   'rootPath': a:root_path,
     \   'capabilities': {},
+    \   'initializationOptions': a:initialization_options,
     \}]
 endfunction