[firebase_messaging]: Android can no longer subscribe to topics with encoded characters

[amandaoneal]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Messaging

Which platforms are affected?

Android

Description

In the past, I could subscribe to a topic with an encoded apostrophe. For example, a topic named "o%27neal" (no quotes).

Now, when I try to do so, it always hangs, and sometimes prints "Failed to sync topics. Won't retry sync. Topic subscribe failed with status: 400". After this happens, Firebase Messaging is in a bad state; I can no longer subscribe or unsubscribe to any topic unless I uninstall/reinstall the app.

This seems to be Android-specific; I could not repro it on iOS. It is happening for other characters than the apostrophe as well, but I haven't narrowed down the exact character set.

If I revert to the previous version I was using, firebase_messaging 16.2.2, it resolves this issue. So it showed up somewhere between 16.2.2 and 16.5.0.

Reproducing the issue

(set up firebase normally)

await firebaseMessaging.subscribeToTopic("o%27neal");

Firebase Core version

4.13.0

Flutter Version

3.44.0

Relevant Log Output

Flutter dependencies

Expand Flutter dependencies snippet

Dart SDK 3.12.0
Flutter SDK 3.44.0
alerts_for_reddit 3.6.1+35

dependencies:
- age_range_signals 0.8.0 [flutter plugin_platform_interface]
- connectivity_plus 7.3.1 [flutter flutter_web_plugins connectivity_plus_platform_interface web meta nm collection]
- crypto 3.0.7 [typed_data]
- cupertino_icons 1.0.9
- device_info_plus 13.2.0 [device_info_plus_platform_interface ffi file flutter flutter_web_plugins meta web win32 win32_registry]
- file 7.0.1 [meta path]
- firebase_analytics 12.4.6 [firebase_analytics_platform_interface firebase_analytics_web firebase_core firebase_core_platform_interface flutter]
- firebase_app_installations 0.4.2+7 [firebase_app_installations_platform_interface firebase_app_installations_web firebase_core firebase_core_platform_interface flutter]
- firebase_core 4.13.0 [firebase_core_platform_interface firebase_core_web flutter meta]
- firebase_messaging 16.5.0 [firebase_core firebase_core_platform_interface firebase_messaging_platform_interface firebase_messaging_web flutter meta]
- flutter 0.0.0 [characters collection material_color_utilities meta vector_math sky_engine]
- flutter_local_notifications 22.3.0 [clock flutter flutter_local_notifications_linux flutter_local_notifications_windows flutter_local_notifications_web flutter_local_notifications_platform_interface timezone]
- flutter_timezone 4.1.1 [flutter flutter_web_plugins]
- html_unescape 2.0.0
- http 1.6.0 [async http_parser meta web]
- in_app_review 2.0.12 [flutter in_app_review_platform_interface]
- intl 0.20.3 [clock meta path]
- oauth2 2.0.5 [collection crypto http http_parser]
- purchases_flutter 10.8.0 [flutter flutter_web_plugins web equatable meta]
- share_plus 13.3.0 [cross_file meta mime flutter flutter_web_plugins share_plus_platform_interface file url_launcher_web url_launcher_windows url_launcher_linux url_launcher_platform_interface ffi web win32]
- shared_preferences 2.5.5 [flutter shared_preferences_android shared_preferences_foundation shared_preferences_linux shared_preferences_platform_interface shared_preferences_web shared_preferences_windows]
- url_launcher 6.3.2 [flutter url_launcher_android url_launcher_ios url_launcher_linux url_launcher_macos url_launcher_platform_interface url_launcher_web url_launcher_windows]

dev dependencies:
- flutter_test 0.0.0 [flutter test_api matcher path fake_async clock stack_trace vector_math leak_tracker_flutter_testing collection meta stream_channel]

transitive dependencies:
- _flutterfire_internals 1.3.76 [collection firebase_core firebase_core_platform_interface flutter meta]
- args 2.7.0
- async 2.13.1 [collection meta]
- boolean_selector 2.1.2 [source_span string_scanner]
- characters 1.4.1
- clock 1.1.2
- code_assets 1.2.0 [collection hooks]
- collection 1.19.1
- connectivity_plus_platform_interface 2.1.0 [flutter meta plugin_platform_interface]
- cross_file 0.3.5+2 [meta web]
- dbus 0.7.12 [args ffi meta xml]
- device_info_plus_platform_interface 8.1.0 [flutter meta plugin_platform_interface]
- equatable 2.0.8 [collection meta]
- fake_async 1.3.3 [clock collection]
- ffi 2.2.0
- ffi_leak_tracker 0.1.2 [ffi]
- firebase_analytics_platform_interface 6.0.6 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_analytics_web 0.6.1+12 [_flutterfire_internals firebase_analytics_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins]
- firebase_app_installations_platform_interface 0.1.4+75 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_app_installations_web 0.1.7+12 [_flutterfire_internals firebase_app_installations_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins]
- firebase_core_platform_interface 8.1.1 [collection flutter meta plugin_platform_interface]
- firebase_core_web 3.11.0 [firebase_core_platform_interface flutter flutter_web_plugins meta web]
- firebase_messaging_platform_interface 4.9.3 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_messaging_web 4.2.4 [_flutterfire_internals firebase_core firebase_core_web firebase_messaging_platform_interface flutter flutter_web_plugins meta web]
- fixnum 1.1.1
- flutter_local_notifications_linux 8.0.1 [dbus ffi flutter flutter_local_notifications_platform_interface path xdg_directories]
- flutter_local_notifications_platform_interface 12.2.0 [plugin_platform_interface timezone]
- flutter_local_notifications_web 1.0.0 [collection flutter flutter_local_notifications_platform_interface timezone web]
- flutter_local_notifications_windows 3.1.1 [flutter ffi flutter_local_notifications_platform_interface meta timezone xml]
- flutter_web_plugins 0.0.0 [flutter]
- hooks 2.0.0 [collection crypto logging meta pub_semver record_use yaml]
- http_parser 4.1.2 [collection source_span string_scanner typed_data]
- in_app_review_platform_interface 2.0.5 [flutter url_launcher plugin_platform_interface platform]
- jni 1.0.0 [args collection ffi meta package_config path plugin_platform_interface]
- jni_flutter 1.0.1 [flutter jni]
- leak_tracker 11.0.2 [clock collection meta path vm_service]
- leak_tracker_flutter_testing 3.0.10 [flutter leak_tracker leak_tracker_testing matcher meta]
- leak_tracker_testing 3.0.2 [leak_tracker matcher meta]
- logging 1.3.0
- matcher 0.12.19 [async meta stack_trace term_glyph test_api]
- material_color_utilities 0.13.0 [collection]
- meta 1.18.0
- mime 2.0.0
- nm 0.5.0 [dbus]
- objective_c 9.4.1 [code_assets collection ffi hooks logging meta pub_semver]
- package_config 2.2.0 [path]
- path 1.9.1
- path_provider 2.1.5 [flutter path_provider_android path_provider_foundation path_provider_linux path_provider_platform_interface path_provider_windows]
- path_provider_android 2.3.1 [flutter jni jni_flutter path_provider_platform_interface]
- path_provider_foundation 2.6.0 [ffi flutter objective_c path_provider_platform_interface]
- path_provider_linux 2.2.1 [ffi flutter path path_provider_platform_interface xdg_directories]
- path_provider_platform_interface 2.1.2 [flutter platform plugin_platform_interface]
- path_provider_windows 2.3.0 [ffi flutter path path_provider_platform_interface]
- petitparser 7.0.2 [meta collection]
- platform 3.1.6
- plugin_platform_interface 2.1.8 [meta]
- pub_semver 2.2.0 [collection]
- record_use 0.6.0 [collection meta pub_semver]
- share_plus_platform_interface 7.2.0 [cross_file flutter meta mime plugin_platform_interface path_provider uuid]
- shared_preferences_android 2.4.23 [flutter shared_preferences_platform_interface]
- shared_preferences_foundation 2.5.6 [flutter shared_preferences_platform_interface]
- shared_preferences_linux 2.4.1 [file flutter path path_provider_linux path_provider_platform_interface shared_preferences_platform_interface]
- shared_preferences_platform_interface 2.4.2 [flutter plugin_platform_interface]
- shared_preferences_web 2.4.3 [flutter flutter_web_plugins shared_preferences_platform_interface web]
- shared_preferences_windows 2.4.1 [file flutter path path_provider_platform_interface path_provider_windows shared_preferences_platform_interface]
- sky_engine 0.0.0
- source_span 1.10.2 [collection path term_glyph]
- stack_trace 1.12.1 [path]
- stream_channel 2.1.4 [async]
- string_scanner 1.4.1 [source_span]
- term_glyph 1.2.2
- test_api 0.7.11 [async boolean_selector collection meta source_span stack_trace stream_channel string_scanner term_glyph]
- timezone 0.11.1 [http path]
- typed_data 1.4.0 [collection]
- url_launcher_android 6.3.29 [flutter url_launcher_platform_interface]
- url_launcher_ios 6.4.1 [flutter url_launcher_platform_interface]
- url_launcher_linux 3.2.2 [flutter url_launcher_platform_interface]
- url_launcher_macos 3.2.5 [flutter url_launcher_platform_interface]
- url_launcher_platform_interface 2.3.2 [flutter plugin_platform_interface]
- url_launcher_web 2.4.2 [flutter flutter_web_plugins url_launcher_platform_interface web]
- url_launcher_windows 3.1.5 [flutter url_launcher_platform_interface]
- uuid 4.5.3 [crypto fixnum]
- vector_math 2.2.0
- vm_service 15.1.0
- web 1.1.1
- win32 6.4.0 [ffi ffi_leak_tracker meta]
- win32_registry 3.0.3 [collection ffi ffi_leak_tracker meta win32]
- xdg_directories 1.1.0 [meta path]
- xml 6.6.1 [collection meta petitparser]
- yaml 3.1.3 [collection source_span string_scanner]

Additional context and comments

No response

[amandaoneal]

After digging into this more, I have a guess. The guess would put the problem in the firebase-android-sdk repository.

Here's my guess: TopicSubscriptionClient, which is a new file as of the FCM V1 API Migration initial commit, on line 110 creates a URL for the call to fcmregistrations.googleapis.com, and the "topic" part of that URL path is not encoded. So my guess is that the server is decoding that unencoded path, which is what's causing this problem. The fix would be for TopicSubscriptionClient to encode the topic for that URL.

As a note, the equivalent call from firebase-ios-sdk DOES encode the topic (see here)

[amandaoneal]

It appears there is already a PR for a fix to this: firebase/firebase-android-sdk#8553

Leaving this issue open until the fix actually goes through.

[SelaseKay]

Hi @amandaoneal, thanks for the detailed report. Keeping this opened untill fix is merged and released upstream.