[cloud-firestore] Transactions fail with PlatformException

[YohanWadia]

Hi,
Searched every where... and seen a lot of bugs with Transactions in Firestore pkg... but this one is new.

• Im running it on stable channel(Android Studio)
• Ive got the same error on device and emulator (Both Androids)
• All my other CRUD operations work perfectly.

CODE:

DocumentReference myDocRef = collectionRef.document("Uuid");
    Firestore.instance.runTransaction((Transaction tx) async {
      print("000000");
      DocumentSnapshot docSnap = await tx.get(myDocRef);
      int x= docSnap.data['age'];
      x++;print("Age ++: $x");
      await tx.update(myDocRef, <String, dynamic>{'age': x})
          .catchError((e) {print("ERROR= $e");})
          .whenComplete(() {print("Transaction DONE!!!");});
    });

the above Document has only 2 fields: name & age. Im trying to read age... and then increment it by +1... and then update the document with the new age.
the above code fails even before it can print "000000".

> ERROR:
> PlatformException(Error performing transaction, Attempt to invoke virtual method 'void android.app.Activity.runOnUiThread(java.lang.Runnable)' on a null object reference, null)


> FULL ERROR:
> E/flutter (22677): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(Error performing transaction, Attempt to invoke virtual method 'void android.app.Activity.runOnUiThread(java.lang.Runnable)' on a null object reference, null)
> E/flutter (22677): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
> E/flutter (22677): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:321:33)
> E/flutter (22677): <asynchronous suspension>
> E/flutter (22677): #2      MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart:349:48)
> E/flutter (22677): #3      MethodChannelFirestore.runTransaction (package:cloud_firestore_platform_interface/src/method_channel/method_channel_firestore.dart:123:10)
> E/flutter (22677): #4      Firestore.runTransaction (package:cloud_firestore/src/firestore.dart:85:22)
> E/flutter (22677): #5      _MyHomePageState.UpdateTransactionRW (package:firestorecrud/main.dart:229:24)
> E/flutter (22677): #6      _MyHomePageState.build.<anonymous closure> (package:firestorecrud/main.dart:90:19)
> E/flutter (22677): #7      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
> E/flutter (22677): #8      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
> E/flutter (22677): #9      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
> E/flutter (22677): #10     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
> E/flutter (22677): #11     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
> E/flutter (22677): #12     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:199:7)
> E/flutter (22677): #13     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:467:9)
> E/flutter (22677): #14     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
> E/flutter (22677): #15     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:117:9)
> E/flutter (22677): #16     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
> E/flutter (22677): #17     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:115:18)
> E/flutter (22677): #18     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:7)
> E/flutter (22677): #19     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
> E/flutter (22677): #20     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
> E/flutter (22677): #21     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
> E/flutter (22677): #22     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
> E/flutter (22677): #23     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
> E/flutter (22677): #24     _rootRunUnary (dart:async/zone.dart:1138:13)
> E/flutter (22677): #25     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
> E/flutter (22677): #26     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
> E/flutter (22677): #27     _invoke1 (dart:ui/hooks.dart:273:10)
> E/flutter (22677): #28     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)

====================
flutter doctor -v

[√] Flutter (Channel stable, v1.12.13+hotfix.9, on Microsoft Windows [Version 10.0.18363.720], locale en-US)
    • Flutter version 1.12.13+hotfix.9 at C:\flutterio\flutter
    • Framework revision f139b11009 (4 days ago), 2020-03-30 13:57:30 -0700
    • Engine revision af51afceb8
    • Dart version 2.7.2


[√] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at C:\Users\Yo\AppData\Local\Android\sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.2
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
    • All Android licenses accepted.

[√] Android Studio (version 3.6)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin version 44.0.2
    • Dart plugin version 192.7761
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)

[!] IntelliJ IDEA Community Edition (version 2019.2)
    • IntelliJ at D:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.2.3
    X Flutter plugin not installed; this adds Flutter specific functionality.
    X Dart plugin not installed; this adds Dart specific functionality.
    • For information about installing plugins, see
      https://flutter.dev/intellij-setup/#installing-the-plugins

[!] VS Code (version 1.43.0)
    • VS Code at C:\Users\Yo\AppData\Local\Programs\Microsoft VS Code
    X Flutter extension not installed; install from
      https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[√] Connected device (1 available)
    • AOSP on IA Emulator • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

! Doctor found issues in 2 categories.

[YohanWadia]

@iapicca , I just checked back after bit of time... has anything developed on this topic?

[Salakar]

Hey, as part of our on-going work for #2582, this has been resolved in our Firebase Firestore rework (#2913) - which has now been merged into master. We'll look at publishing some prereleases in the next few days. Thank you