Realtime DB updates offline to online connection status with big delay of more than 10 minutes

[alexander-at-t]

Operating System

macOS Sonoma 14.6.1

Environment (if applicable)

Chrome 130

Firebase SDK Version

11.2.0

Firebase SDK Product(s)

Database

Project Tooling

Javascript + React + Webpack

Detailed Problem Description

Realtime should quickly reconnect after connection lost.

But there is a bug in Firebase JS SDK that leads to delays before reconnect attempt that exceeds max constant values.

Steps and code to reproduce issue

Steps

1. Be online
2. Open application that uses Realtime DB
3. Change client computer clock (decrease time by 15 minutes, for example set 14:30 instead of 14:45)
4. Turn off wifi

You will see that Realtime DB may try to reconnect in 3 minutes even for Admin accounts (for Admin accounts constant maximum is 30 seconds).

The bug is in this code:

firebase-js-sdk/packages/database/src/core/PersistentConnection.ts

Lines 800 to 815 in b12af44

	const timeSinceLastConnectAttempt =
	new Date().getTime() - this.lastConnectionAttemptTime_;
	let reconnectDelay = Math.max(
	0,
	this.reconnectDelay_ - timeSinceLastConnectAttempt
	);
	reconnectDelay = Math.random() * reconnectDelay;
	this.log_('Trying to reconnect in ' + reconnectDelay + 'ms');
	this.scheduleConnect_(reconnectDelay);
	// Adjust reconnect delay for next time.
	this.reconnectDelay_ = Math.min(
	this.maxReconnectDelay_,
	this.reconnectDelay_ * RECONNECT_DELAY_MULTIPLIER
	);

So timeSinceLastConnectAttempt may become negative, and so lead to significant exceeding of max delays defined in constants.

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