Duplicate topic check should only check for duplicates within a forum

[r-a-y]

The duplicate topic check currently checks if a topic is the same across all forums.

We've run into a scenario where there is a forum user who administrates several forums. This user wants to write the same "Introduction" forum topic with the same content for each forum. However, if you're not a super admin, this is not possible.

I would suggest to restrict the duplicate topic check to the specific forum. See attached patch.

[johnjamesjacoby]

Hey @r-a-y! This seems OK to me.

Any thoughts about adding the same checks to Forums or Replies?

[r-a-y]

No need to do the same thing for replies. The duplicate reply check already checks within the existing topic and not across all forum replies.

Up to you regarding forums. Might be useful for huge forums utilizing sub-forums that might want to re-use the same forum name.

[johnjamesjacoby]

Adding support for all post types.

[johnjamesjacoby]

In 7207:

Content: add post_parent to forum & topic duplicate checks.

This change limits the scope of "duplicate content" to its parent context, meaning that replies must be to the same topic, topics must be in the same forum, and forums must be in the same sub-forum (or root) to be considered a duplicate.

This better implements the spirit of this feature which is to prevent accidental/unintended duplicates, and is not intended to simply prevent globally similar content by the same author.

Props r-a-y, johnjamesjacoby.

In trunk, for 2.7.0.

See #3418.

[johnjamesjacoby]

In 7208:

Content: add post_parent to forum & topic duplicate checks.

This change limits the scope of "duplicate content" to its parent context, meaning that replies must be to the same topic, topics must be in the same forum, and forums must be in the same sub-forum (or root) to be considered a duplicate.

This better implements the spirit of this feature which is to prevent accidental/unintended duplicates, and is not intended to simply prevent globally similar content by the same author.

Props r-a-y, johnjamesjacoby.

In branches/2.6, for 2.6.7.

Fixes #3418.