lsp: add workspace/symbol (#12224)

* lsp: add workspace/symbol
* refactor symbol callback
* set hierarchical symbol support to true
* add documentation and default mapping

Co-authored-by: Hirokazu Hata <h.hata.ai.t@gmail.com>

runtime/lua/vim/lsp.lua

@@ -533,6 +533,7 @@ function lsp.start_client(config)
       or (not client.resolved_capabilities.goto_definition and method == 'textDocument/definition')
       or (not client.resolved_capabilities.implementation and method == 'textDocument/implementation')
       or (not client.resolved_capabilities.document_symbol and method == 'textDocument/documentSymbol')
+      or (not client.resolved_capabilities.workspace_symbol and method == 'textDocument/workspaceSymbol')
     then
       callback(unsupported_method(method), method, nil, client_id, bufnr)
       return

runtime/lua/vim/lsp/buf.lua

@@ -137,6 +137,12 @@ function M.document_symbol()
   request('textDocument/documentSymbol', params)
 end
 
+function M.workspace_symbol(query)
+  query = query or npcall(vfn.input, "Query: ")
+  local params = {query = query}
+  request('workspace/symbol', params)
+end
+
 --- Send request to server to resolve document highlights for the
 --- current text document position. This request can be associated
 --- to key mapping or to events such as `CursorHold`, eg:

runtime/lua/vim/lsp/callbacks.lua

@@ -54,13 +54,15 @@ M['textDocument/references'] = function(_, _, result)
   api.nvim_command("wincmd p")
 end
 
-M['textDocument/documentSymbol'] = function(_, _, result, _, bufnr)
+local symbol_callback = function(_, _, result, _, bufnr)
   if not result or vim.tbl_isempty(result) then return end
 
   util.set_qflist(util.symbols_to_items(result, bufnr))
   api.nvim_command("copen")
   api.nvim_command("wincmd p")
 end
+M['textDocument/documentSymbol'] = symbol_callback
+M['workspace/symbol'] = symbol_callback
 
 M['textDocument/rename'] = function(_, _, result)
   if not result then return end

runtime/lua/vim/lsp/protocol.lua

@@ -688,6 +688,19 @@ function protocol.make_client_capabilities()
         };
         hierarchicalDocumentSymbolSupport = true;
       };
+      workspaceSymbol = {
+        dynamicRegistration = false;
+        symbolKind = {
+          valueSet = (function()
+            local res = {}
+            for k in pairs(protocol.SymbolKind) do
+              if type(k) == 'number' then table.insert(res, k) end
+            end
+            return res
+          end)();
+        };
+        hierarchicalWorkspaceSymbolSupport = true;
+      };
     };
     workspace = nil;
     experimental = nil;