User Session Recording Results in Error

[dehli]

Bug description

Yesterday we started getting an error in our app triggered from Posthog hosted code:

Cannot read properties of null (reading 'tagName')

I was able to debug that it's related to user session recordings and disabling them prevents the error from showing more.

I have left it enabled on our dev instance so it can be more easily debugged.

How to reproduce

1. Visit https://dev.vistaly.com
2. Sign-in with: <redacted>
3. Visit https://dev.vistaly.com/w/qewwIlH4Xf1R0cAt7jdOm
4. Delete the card text (by clicking on it and then removing it in editor) and then start interacting in the app

5. See console filled with error messages:

Environment

• PostHog Cloud US, project ID: 29524

Additional context

• https://posthog.com/questions/enabling-record-user-sessions-generates-cannot-read-properties-of-null-reading-tag-name

[daibhin]

Thank you very much for the reproduction steps @dehli.

It looks like the latest version of our web capture tool (rrweb) made the changes causing this issue in a PR that was merged in the latest release: rrweb-io/rrweb#1351. We upgraded to the latest release yesterday, which perfectly lines up with when the error started occurring for you.

I've shipped a fix to their repo: rrweb-io/rrweb#1445 and added a patch to our own repo PostHog/posthog-js#1125

Thanks for reporting this 🙏

[dehli]

Thanks @daibhin for the speedy fix! Happy to help 😄 Should I go ahead and close issue or wait until the fix is deployed?

[daibhin]

Let's wait until the fix gets out and you're confident that the issue has been fixed for you

[bookee-sid]

Hey @daibhin, when can we expect this fix to be merged and deployed? Can we get a ETA on this. Thanks

[daibhin]

@bookee-sid I just merged the change. I should be live in the next hour or so. It will require that you upgrade your PostHog SDK to the latest version

[dehli]

Thanks again @daibhin for the quick fix! Just confirmed that the error is no longer occurring so I will go ahead and close this issue. Have a good one!

[daibhin]

Amazing, thanks @dehli for confirming