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Michael Lehenbauer
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Offline get() improvements.
[Port of firebase/firebase-js-sdk#1133] 1. Changed MAX_WATCH_STREAM_FAILURES to 1 per conversation with @wilhuff and @jdimond. 2. Fixed a "race" where when a get() triggered a watch stream error, we'd restart the stream, then get() would remove its listener, and so we had no listener left once the watch stream was "opened". Without a listen to send we'd be stuck in Offline state (even though we should be Unknown whenever we have no listens to send), resulting in the next get() returning data from cache without even attempting to reach the backend.
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‎firebase-firestore/CHANGELOG.md

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@@ -1,4 +1,11 @@
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# Unreleased
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- [fixed] Fixed an issue where the first `get()` call made after being offline
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could incorrectly return cached data without attempting to reach the backend.
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- [changed] Changed `get()` to only make 1 attempt to reach the backend before
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returning cached data, potentially reducing delays while offline. Previously
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it would make 2 attempts, to work around a backend bug.
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# 17.1.0
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- [feature] Added `FieldValue.arrayUnion()` and `FieldValue.arrayRemove()` to
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atomically add and remove elements from an array field in a document.
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- [feature] Added `Query.whereArrayContains()` query operator to find documents

‎firebase-firestore/src/main/java/com/google/firebase/firestore/remote/OnlineStateTracker.java

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@@ -46,7 +46,10 @@ interface OnlineStateCallback {
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// To deal with transient failures, we allow multiple stream attempts before giving up and
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// transitioning from OnlineState.UNKNOWN to OFFLINE.
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private static final int MAX_WATCH_STREAM_FAILURES = 2;
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// TODO(mikelehen): This used to be set to 2 as a mitigation for b/66228394. @jdimond thinks that
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// bug is sufficiently fixed so that we can set this back to 1. If that works okay, we could
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// potentially remove this logic entirely.
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private static final int MAX_WATCH_STREAM_FAILURES = 1;
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// To deal with stream attempts that don't succeed or fail in a timely manner, we have a
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// timeout for OnlineState to reach ONLINE or OFFLINE. If the timeout is reached, we transition

‎firebase-firestore/src/main/java/com/google/firebase/firestore/remote/RemoteStore.java

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@@ -325,8 +325,16 @@ public void stopListening(int targetId) {
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// The watch stream might not be started if we're in a disconnected state
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if (watchStream.isOpen()) {
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sendUnwatchRequest(targetId);
328-
if (listenTargets.isEmpty()) {
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}
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if (listenTargets.isEmpty()) {
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if (watchStream.isOpen()) {
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watchStream.markIdle();
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} else if (this.canUseNetwork()) {
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// Revert to OnlineState.UNKNOWN if the watch stream is not open and we have no listeners,
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// since without any listens to send we cannot confirm if the stream is healthy and upgrade
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// to OnlineState.ONLINE.
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this.onlineStateTracker.updateState(OnlineState.UNKNOWN);
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}
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}
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}

‎firebase-firestore/src/test/java/com/google/firebase/firestore/spec/SpecTestCase.java

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@@ -133,6 +133,7 @@ public abstract class SpecTestCase implements RemoteStoreCallback {
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: Sets.newHashSet("no-android", "benchmark", "multi-client");
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private boolean garbageCollectionEnabled;
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private boolean networkEnabled = true;
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//
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// Parts of the Firestore system that the spec tests need to control.
@@ -670,6 +671,7 @@ private void doDrainQueue() throws Exception {
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}
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private void doDisableNetwork() throws Exception {
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networkEnabled = false;
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queue.runSync(
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() -> {
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// Make sure to execute all writes that are currently queued. This allows us
@@ -680,6 +682,7 @@ private void doDisableNetwork() throws Exception {
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}
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private void doEnableNetwork() throws Exception {
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networkEnabled = true;
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queue.runSync(() -> remoteStore.enableNetwork());
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}
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@@ -939,6 +942,10 @@ private void validateLimboDocs() {
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}
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private void validateActiveTargets() {
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if (!networkEnabled) {
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return;
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}
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// Create a copy so we can modify it in tests
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Map<Integer, QueryData> actualTargets = new HashMap<>(datastore.activeTargets());
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‎firebase-firestore/src/test/resources/json/offline_spec_test.json

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Original file line numberDiff line numberDiff line change
@@ -2,10 +2,7 @@
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"Empty queries are resolved if client goes offline": {
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"describeName": "Offline:",
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"itName": "Empty queries are resolved if client goes offline",
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"tags": [
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"no-android",
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"no-ios"
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],
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"tags": [],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
@@ -77,10 +74,7 @@
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"A successful message delays offline status": {
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"describeName": "Offline:",
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"itName": "A successful message delays offline status",
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"tags": [
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"no-android",
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"no-ios"
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],
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"tags": [],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
@@ -167,9 +161,7 @@
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"describeName": "Offline:",
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"itName": "Removing all listeners delays \"Offline\" status on next listen",
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"tags": [
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"eager-gc",
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"no-android",
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"no-ios"
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"eager-gc"
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],
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"comment": "Marked as no-lru because when a listen is re-added, it gets a new target id rather than reusing one",
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"config": {
@@ -290,10 +282,7 @@
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"Queries revert to fromCache=true when offline.": {
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"describeName": "Offline:",
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"itName": "Queries revert to fromCache=true when offline.",
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"tags": [
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"no-android",
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"no-ios"
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],
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"tags": [],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
@@ -461,10 +450,7 @@
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"Queries with limbo documents handle going offline.": {
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"describeName": "Offline:",
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"itName": "Queries with limbo documents handle going offline.",
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"tags": [
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"no-android",
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"no-ios"
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],
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"tags": [],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
@@ -889,10 +875,7 @@
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"New queries return immediately with fromCache=true when offline due to stream failures.": {
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"describeName": "Offline:",
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"itName": "New queries return immediately with fromCache=true when offline due to stream failures.",
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"tags": [
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"no-android",
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"no-ios"
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],
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"tags": [],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
@@ -1074,5 +1057,117 @@
10741057
]
10751058
}
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]
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},
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"Queries return from cache when network disabled": {
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"describeName": "Offline:",
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"itName": "Queries return from cache when network disabled",
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"tags": ["eager-gc"],
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"config": {
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"useGarbageCollection": true,
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"numClients": 1
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},
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"steps": [
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{
1071+
"enableNetwork": false,
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"stateExpect": {
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"activeTargets": {},
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"limboDocs": []
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}
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},
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{
1078+
"userListen": [
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2,
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{
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"path": "collection",
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"filters": [],
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"orderBys": []
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}
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],
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"stateExpect": {
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"activeTargets": {
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"2": {
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"query": {
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"path": "collection",
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"filters": [],
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"orderBys": []
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},
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"resumeToken": ""
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}
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}
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},
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"expect": [
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{
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"query": {
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"path": "collection",
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"filters": [],
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"orderBys": []
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},
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"errorCode": 0,
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"fromCache": true,
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"hasPendingWrites": false
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}
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]
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},
1111+
{
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"userUnlisten": [
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2,
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{
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"path": "collection",
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"filters": [],
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"orderBys": []
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}
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],
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"stateExpect": {
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"activeTargets": {}
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}
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},
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{
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"userListen": [
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4,
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{
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"path": "collection",
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"filters": [],
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"orderBys": []
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}
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],
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"stateExpect": {
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"activeTargets": {
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"4": {
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"query": {
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"path": "collection",
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"filters": [],
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"orderBys": []
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},
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"resumeToken": ""
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}
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}
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},
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"expect": [
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{
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"query": {
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"path": "collection",
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"filters": [],
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"orderBys": []
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},
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"errorCode": 0,
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"fromCache": true,
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"hasPendingWrites": false
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}
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]
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},
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{
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"userUnlisten": [
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4,
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{
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"path": "collection",
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"filters": [],
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"orderBys": []
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}
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],
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"stateExpect": {
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"activeTargets": {}
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}
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}
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]
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}
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}

‎firebase-firestore/src/test/resources/json/remote_store_spec_test.json

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@@ -482,10 +482,7 @@
482482
"Cleans up watch state correctly": {
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"describeName": "Remote store:",
484484
"itName": "Cleans up watch state correctly",
485-
"tags": [
486-
"no-android",
487-
"no-ios"
488-
],
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"tags": [],
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"config": {
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"useGarbageCollection": false,
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"numClients": 1

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