Error when adding duplicate entry to adlist

Pi-hole version is v4.3.5-458-g2de5362 (Latest: v4.4)
AdminLTE version is v4.3.2-462-g8e51f754 (Latest: v4.3.3)
FTL version is vDev-d395b3b (Latest: v4.3.1)

When adding for example to the adlist via web gui, it pops up following error:

Error, something went wrong! While executing: UNIQUE constraint failed: adlist.address

If I take off the https:// from the string it imports the list correctly.

Debug Token:

This means the list has already been added, note that you can (and should obviously) import each list only once.

From your debug log, I see that the list was added already on 2020-01-25 19:08:07 with the comment: Migrated from /etc/pihole/adlists.list.

Is there a bug here?

Oh I didn't even think about that. English is not my native language, I didn't understand the error means the entry already exists, but in retrospect I see now how it says exactly that.

I don't think it should be necessary for the whole process to stop if only 1 domain gives an error message.

For example: trying to add many lists with one erroneous (or duplicate) entry somewhere at the top results in an error and all the domains after the erroneous one are not added.

Is that the desired behaviour? In my opinion it would be easier / better if all the other domains that are valid would still be added.

Will be the default behavior in v5.1