@Jesus Maria Mendez Perez @Juanjo Meroño I think that I have found the causes of the bug.

It is not a regression. The issue was not fixed by your patch, only was partially reduced.

When a message is replied, your patch adds the sender of the original message to the recipients list. However, it must be present in totalComposeList in order to be added. This list is filled with everyone who the user which is answering can send to, based on their role's permissions.

If the sender is not in totalComposeList (because the answerer has not permission to send him a message) it can't be added to the recipients list and the issue happens again.

To test this, just remove all permissions from student role, login as an student and try to answer to a message received by him. The bug happens again.

AFAIK this is very hard to fix, because the recipients list is generated with dynamic uuids of allowed users and you can't just add one more recipient to a message if the uuid is not in the list.

And anyway I'm not sure if a user that is not allowed to send a message to nobody should be even allowed to reply.

@Jesus Maria Mendez Perez no, that patch is not applied in our environment.

Also, I tested it in the 12.x QA server and it failed too. So if it is a regression it must be in a 12.x merged patch.

If I find anything I'll let you know.

Hi @Daniel Merino.

Is possible that this change is affecting?

https://github.com/sakaiproject/sakai/commit/b104f9a313fac4ce71023e71342cc8ce09e82a4a#diff-6975b06d309f37b2d7d8b5bc28fae443R2316

Is https://sakaiproject.atlassian.net/browse/SAK-42557#icft=SAK-42557 in your 12.6?

@Jesus Maria Mendez Perez @Juanjo Meroño

We have been affected by this issue in 12.6.

I have tested it in 12.x QA server ( https://qa12-mysql.nightly.sakaiproject.org/portal ) and the test plan fails.

I'm still taking a look on it, but FYI.

I was able to reproduce the problem on the 11.x qa server , but not on master, where the fix has been applied.