log: Add reportErrorModally

Signed-off-by: Zixuan James Li <zixuan@zulip.com>

Author: PIG208

lib/log.dart

@@ -32,6 +32,7 @@ bool debugLog(String message) {
 }
 
 typedef ReportErrorCancellablyCallback = void Function(String? message, {String? details});
+typedef ReportErrorCallback = void Function(String message, {String? details});
 
 /// Show the user an error message, without requiring them to interact with it.
 ///
@@ -50,6 +51,17 @@ typedef ReportErrorCancellablyCallback = void Function(String? message, {String?
 // the app.
 ReportErrorCancellablyCallback reportErrorToUserBriefly = defaultReportErrorToUserBriefly;
 
+/// Show the user a dismissable error message in a modal popup.
+///
+/// Typically this shows a [AlertDialog] containing the message.
+/// If called before the app's widget tree is ready (see [ZulipApp.ready]),
+/// then we give up on showing the message to the user,
+/// and just log the message to the console.
+// This gets set in [ZulipApp].  We need this indirection to keep `lib/log.dart`
+// from importing widget code, because the file is a dependency for the rest of
+// the app.
+ReportErrorCallback reportErrorToUserModally = defaultReportErrorToUserBriefly;
+
 void defaultReportErrorToUserBriefly(String? message, {String? details}) {
   // Error dismissing is a no-op to the default handler.
   if (message == null) return;

lib/widgets/app.dart

@@ -85,6 +85,7 @@ class ZulipApp extends StatefulWidget {
   static void debugReset() {
     _snackBarCount = 0;
     reportErrorToUserBriefly = defaultReportErrorToUserBriefly;
+    reportErrorToUserModally = defaultReportErrorToUserBriefly;
     _ready.dispose();
     _ready = ValueNotifier(false);
   }
@@ -128,10 +129,21 @@ class ZulipApp extends StatefulWidget {
     newSnackBar.closed.whenComplete(() => _snackBarCount--);
   }
 
+  /// The callback we normally use as [reportErrorToUserModally].
+  static void _reportErrorToUserModally(String message, {String? details}) {
+    assert(_ready.value);
+
+    showErrorDialog(
+      context: navigatorKey.currentContext!,
+      title: message,
+      message: details);
+  }
+
   void _declareReady() {
     assert(navigatorKey.currentContext != null);
     _ready.value = true;
     reportErrorToUserBriefly = _reportErrorToUserBriefly;
+    reportErrorToUserModally = _reportErrorToUserModally;
   }
 
   @override

test/widgets/app_test.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_checks/flutter_checks.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:zulip/log.dart';
 import 'package:zulip/model/database.dart';
@@ -361,5 +362,24 @@ void main() {
       await tester.pumpAndSettle();
       check(findSnackBarByText('unrelated').evaluate()).single;
     });
+
+    testWidgets('reportErrorToUserModally', (tester) async {
+      addTearDown(testBinding.reset);
+      await tester.pumpWidget(const ZulipApp());
+      const message = 'test error message';
+      const details = 'details';
+
+      // Prior to app startup, reportErrorToUserModally only logs.
+      reportErrorToUserModally(message, details: details);
+      check(ZulipApp.ready).value.isFalse();
+      await tester.pump();
+      check(find.byType(AlertDialog)).findsNothing();
+
+      check(ZulipApp.ready).value.isTrue();
+      // After app startup, reportErrorToUserModally displays an [AlertDialog].
+      reportErrorToUserModally(message, details: details);
+      await tester.pump();
+      checkErrorDialog(tester, expectedTitle: message, expectedMessage: details);
+    });
   });
 }