Revert #2416

I got to eager.

Author: Techatrix

src/Server.zig

@@ -615,9 +615,7 @@ fn initializedHandler(server: *Server, arena: std.mem.Allocator, notification: t
 
     server.status = .initialized;
 
-    if (server.client_capabilities.supports_configuration and
-        server.client_capabilities.supports_workspace_did_change_configuration_dynamic_registration)
-    {
+    if (server.client_capabilities.supports_workspace_did_change_configuration_dynamic_registration) {
         try server.registerCapability("workspace/didChangeConfiguration", null);
     }
 
@@ -677,15 +675,25 @@ fn registerCapability(server: *Server, method: []const u8, registersOptions: ?ty
     server.allocator.free(json_message);
 }
 
-/// Request configuration options with the `workspace/configuration` request.
 fn requestConfiguration(server: *Server) Error!void {
-    const configuration_items: [1]types.ConfigurationItem = .{
-        .{
-            .section = "zls",
-            .scopeUri = if (server.workspaces.items.len == 1) server.workspaces.items[0].uri else null,
-        },
+    var configuration_items = comptime config: {
+        var comp_config: [std.meta.fields(Config).len]types.ConfigurationItem = undefined;
+        for (std.meta.fields(Config), 0..) |field, index| {
+            comp_config[index] = .{
+                .section = "zls." ++ field.name,
+            };
+        }
+
+        break :config comp_config;
     };
 
+    if (server.workspaces.items.len == 1) {
+        const workspace = server.workspaces.items[0];
+        for (&configuration_items) |*item| {
+            item.*.scopeUri = workspace.uri;
+        }
+    }
+
     const json_message = try server.sendToClientRequest(
         .{ .string = "i_haz_configuration" },
         "workspace/configuration",
@@ -696,28 +704,18 @@ fn requestConfiguration(server: *Server) Error!void {
     server.allocator.free(json_message);
 }
 
-/// Handle the response of the `workspace/configuration` request.
 fn handleConfiguration(server: *Server, json: std.json.Value) error{OutOfMemory}!void {
     const tracy_zone = tracy.trace(@src());
     defer tracy_zone.end();
 
-    const result: std.json.Value = switch (json) {
-        .array => |arr| blk: {
-            if (arr.items.len != 1) {
-                log.err("Response to 'workspace/configuration' expects an array of size 1 but received {d}", .{arr.items.len});
-                return;
-            }
-            break :blk switch (arr.items[0]) {
-                .object => arr.items[0],
-                .null => return,
-                else => {
-                    log.err("Response to 'workspace/configuration' expects an array of objects but got an array of {t}.", .{json});
-                    return;
-                },
-            };
+    const fields = std.meta.fields(configuration.Configuration);
+    const result = switch (json) {
+        .array => |arr| if (arr.items.len == fields.len) arr.items else {
+            log.err("workspace/configuration expects an array of size {d} but received {d}", .{ fields.len, arr.items.len });
+            return;
         },
         else => {
-            log.err("Response to 'workspace/configuration' expects an array but received {t}", .{json});
+            log.err("workspace/configuration expects an array but received {t}", .{json});
             return;
         },
     };
@@ -726,15 +724,20 @@ fn handleConfiguration(server: *Server, json: std.json.Value) error{OutOfMemory}
     defer arena_allocator.deinit();
     const arena = arena_allocator.allocator();
 
-    var new_config = std.json.parseFromValueLeaky(
-        configuration.Configuration,
-        arena,
-        result,
-        .{ .ignore_unknown_fields = true },
-    ) catch |err| {
-        log.err("Failed to parse response from 'workspace/configuration': {}", .{err});
-        return;
-    };
+    var new_config: configuration.Configuration = .{};
+
+    inline for (fields, result) |field, json_value| {
+        var runtime_known_field_name: []const u8 = ""; // avoid unnecessary function instantiations of `std.Io.Writer.print`
+        runtime_known_field_name = field.name;
+
+        const maybe_new_value = std.json.parseFromValueLeaky(field.type, arena, json_value, .{}) catch |err| blk: {
+            log.err("failed to parse configuration option '{s}': {}", .{ runtime_known_field_name, err });
+            break :blk null;
+        };
+        if (maybe_new_value) |new_value| {
+            @field(new_config, field.name) = new_value;
+        }
+    }
 
     const maybe_root_dir: ?[]const u8 = if (server.workspaces.items.len == 1) dir: {
         const uri = std.Uri.parse(server.workspaces.items[0].uri) catch |err| {
@@ -943,26 +946,13 @@ fn didChangeWorkspaceFoldersHandler(server: *Server, arena: std.mem.Allocator, n
 fn didChangeConfigurationHandler(server: *Server, arena: std.mem.Allocator, notification: types.DidChangeConfigurationParams) Error!void {
     const settings = switch (notification.settings) {
         .null => {
-            if (server.client_capabilities.supports_configuration and
-                server.client_capabilities.supports_workspace_did_change_configuration_dynamic_registration)
-            {
-                // The client has informed us that the configuration options have
-                // changed. The will request them with `workspace/configuration`.
+            if (server.client_capabilities.supports_configuration) {
                 try server.requestConfiguration();
             }
             return;
         },
-        .object => |object| blk: {
-            if (server.client_capabilities.supports_configuration and
-                server.client_capabilities.supports_workspace_did_change_configuration_dynamic_registration)
-            {
-                log.debug("Ignoring 'workspace/didChangeConfiguration' notification in favor of 'workspace/configuration'", .{});
-                try server.requestConfiguration();
-                return;
-            }
-            break :blk object.get("zls") orelse notification.settings;
-        },
-        else => notification.settings, // We will definitely fail to parse this
+        .object => |object| object.get("zls") orelse notification.settings,
+        else => notification.settings,
     };
 
     const new_config = std.json.parseFromValueLeaky(