Google Chrome tab ID changes in tab's lifetime

Question

I'm implementing a Google Chrome extensions that handles tabs. This includes that I fetch the onCreated, onUpdated and onActivated. Each time, I use the tabId in my logic, initially stored in an array during the handling of onCreated events. In principle, everything works fine.

However, I noticed a glitch. Occasionally, the ID of an already existing tab changes. Thus, a tab has then an ID that is not in my array, which naturally results in errors. I can reproduce this issue in the following use case:

• open 2 or more tabs with different URLs
• load in one tab T a URL that is already loaded in another tab

In this case, two things happen: Firstly, instead of the onUpdated event, the onActivated event for T fires. And secondly, T has now a new ID, typically incremented by 2.

This seems to me far from intuitive. I would even call it a bug. Has anybody an idea what's going here?

Any hints are much appreciated!

Answer 1

It's likely caused by prerendering. This can be detected by listening to the chrome.webNavigation.onTabReplaced or chrome.tabs.onReplaced event. Also refer to the the webNavigation event order section for more details.