apprt/gtk: support new config diagnostics API

src/apprt/gtk/App.zig

@@ -123,9 +123,13 @@ pub fn init(core_app: *CoreApp, opts: Options) !App {
     errdefer config.deinit();
 
     // If we had configuration errors, then log them.
-    if (!config._errors.empty()) {
-        for (config._errors.list.items) |err| {
-            log.warn("configuration error: {s}", .{err.message});
+    if (!config._diagnostics.empty()) {
+        var buf = std.ArrayList(u8).init(core_app.alloc);
+        defer buf.deinit();
+        for (config._diagnostics.items()) |diag| {
+            try diag.write(buf.writer());
+            log.warn("configuration error: {s}", .{buf.items});
+            buf.clearRetainingCapacity();
         }
     }
 
@@ -815,7 +819,7 @@ fn syncConfigChanges(self: *App) !void {
 /// there are new configuration errors and hide the window if the errors
 /// are resolved.
 fn updateConfigErrors(self: *App) !void {
-    if (!self.config._errors.empty()) {
+    if (!self.config._diagnostics.empty()) {
         if (self.config_errors_window == null) {
             try ConfigErrorsWindow.create(self);
             assert(self.config_errors_window != null);

src/apprt/gtk/ConfigErrorsWindow.zig

@@ -28,7 +28,7 @@ pub fn create(app: *App) !void {
 }
 
 pub fn update(self: *ConfigErrors) void {
-    if (self.app.config._errors.empty()) {
+    if (self.app.config._diagnostics.empty()) {
         c.gtk_window_destroy(@ptrCast(self.window));
         return;
     }
@@ -130,8 +130,21 @@ const PrimaryView = struct {
         const buf = c.gtk_text_buffer_new(null);
         errdefer c.g_object_unref(buf);
 
-        for (config._errors.list.items) |err| {
-            c.gtk_text_buffer_insert_at_cursor(buf, err.message, @intCast(err.message.len));
+        var msg_buf: [4096]u8 = undefined;
+        var fbs = std.io.fixedBufferStream(&msg_buf);
+
+        for (config._diagnostics.items()) |diag| {
+            fbs.reset();
+            diag.write(fbs.writer()) catch |err| {
+                log.warn(
+                    "error writing diagnostic to buffer err={}",
+                    .{err},
+                );
+                continue;
+            };
+
+            const msg = fbs.getWritten();
+            c.gtk_text_buffer_insert_at_cursor(buf, msg.ptr, @intCast(msg.len));
             c.gtk_text_buffer_insert_at_cursor(buf, "\n", -1);
         }
 

src/cli/diagnostics.zig

@@ -118,7 +118,7 @@ pub const DiagnosticList = struct {
         return self.list.items.len == 0;
     }
 
-    pub fn items(self: *DiagnosticList) []Diagnostic {
+    pub fn items(self: *const DiagnosticList) []const Diagnostic {
         return self.list.items;
     }
 };