From 1df6bd099771e107dc83de01a1490641e4aa1b78 Mon Sep 17 00:00:00 2001
From: Maurice Parrish <10687576+bparrishMines@users.noreply.github.com>
Date: Mon, 2 Oct 2023 14:12:24 -0400
Subject: [PATCH] fix user agent bug

---
 .../webview_flutter/webview_flutter_wkwebview/CHANGELOG.md   | 4 ++++
 .../example/integration_test/webview_flutter_test.dart       | 1 +
 .../lib/src/webkit_webview_controller.dart                   | 5 ++++-
 .../webview_flutter/webview_flutter_wkwebview/pubspec.yaml   | 2 +-
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md b/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
index 0b0101494c2..4de08406bba 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
+++ b/packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 3.9.1
+
+* Fixes bug where `WebkitWebViewController.getUserAgent` was incorrectly returning an empty String.
+
 ## 3.9.0
 
 * Adds support for `PlatformWebViewController.getUserAgent`.
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/example/integration_test/webview_flutter_test.dart b/packages/webview_flutter/webview_flutter_wkwebview/example/integration_test/webview_flutter_test.dart
index 4c8fd2b30d7..64d7702f209 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/example/integration_test/webview_flutter_test.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/example/integration_test/webview_flutter_test.dart
@@ -313,6 +313,7 @@ Future<void> main() async {
 
     final String? userAgent = await controller.getUserAgent();
     expect(userAgent, isNotNull);
+    expect(userAgent, isNotEmpty);
   });
 
   group('Video playback policy', () {
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart b/packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart
index 6fad6d8aaec..a02ed61069e 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart
+++ b/packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart
@@ -666,7 +666,10 @@ window.addEventListener("error", function(e) {
   @override
   Future<String?> getUserAgent() async {
     final String? customUserAgent = await _webView.getCustomUserAgent();
-    if (customUserAgent != null) {
+    // Despite the official documentation of `WKWebView.customUserAgent`, the
+    // default value seems to be an empty String and not null. It's possible it
+    // could depend on the iOS version, so this checks for both.
+    if (customUserAgent != null && customUserAgent.isNotEmpty) {
       return customUserAgent;
     }
 
diff --git a/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml b/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
index 685c96ec699..63ed6e4db5f 100644
--- a/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml
@@ -2,7 +2,7 @@ name: webview_flutter_wkwebview
 description: A Flutter plugin that provides a WebView widget based on Apple's WKWebView control.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter_wkwebview
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 3.9.0
+version: 3.9.1
 
 environment:
   sdk: ">=2.19.0 <4.0.0"