You're right, at the moment it's assuming that _pageName is unique in the result set — but are you saying that sometimes you're providing that and it isn't an existing page? Could you add your full #cargo_query call here?

The FeedItem class sets the unique ID to url, and then we're changing it to the permalink.

Perhaps you're right, and the simplest thing here is to add e.g. unique_id to the possible result fields, and then use whatever it is.

(Also, I'm not sure what the relevance is of the linked discussion about removing unwanted commas.)

Change 942724 had a related patch set uploaded (by Samwilson; author: Samwilson):

[mediawiki/extensions/Cargo@master] Allow feed display format to override 'unique_id'

https://gerrit.wikimedia.org/r/942724

but are you saying that sometimes you're providing that and it isn't an existing page

Here's the relevant part: |fields=CONCAT("Some text here. ", Tablename._pageName, ". ")=_pageName. So when you add http://wiki... to that you don't get a URL that works.

The principle I suppose is that the feed title might be the wiki page name, might include it, or might be something completely different.

I'm not sure what the relevance is of the linked discussion about removing unwanted commas

My mistake. I've changed that to the relevant talk page link.

[mediawiki/extensions/Cargo@master] Allow feed display format to override 'unique_id'

That looks great.

Change 942724 merged by jenkins-bot:

[mediawiki/extensions/Cargo@master] Allow feed display format to override 'id'

https://gerrit.wikimedia.org/r/942724