TypeError when adding book page

Can you please test the same on Drupal 10.1? 9.5 is just a few weeks from end-of-life.

Update the version and reopen this if you can trigger the exception in Drupal 10.1.

Patch attached to resolve this issue

Yes, i will test this in Drupal 10.1 but this patch is needed for a current Drupal 9 production site.

That's understood of course. It's just that no ordinary bug fixes are ever going to be merged into branch 9.5.x.

So will need tests to show the issue.

But typically with this kind of issues some digging needs to be done to figure out why the value is empty. Putting an isset or empty could be masking a larger issue

have reproduced the error in Drupal 10.1.4, see this issue 🐛 TypeError when adding book page Needs work

Ok, let's close this as a duplicate because it will not be merged. We didn't actually need another issue for this.

Oh, we did the opposite.

Aditi Saraf → made their first commit to this issue’s fork.

Tried this with 11.x version , not getting this issue ..