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Bug in Topic Subscriptions if captions are identical on different pages
Closed, DeclinedPublicBUG REPORT


There seems to be a bug in Topic subscriptions (cf. T263821):

I’ve made an edit request in Commons for gadget LargerGallery with caption Necessary update after change in code base and after creation hit the subscribe topic button.
Then, since it’s the same cause and almost the same fix, I went to the yet unexisting talk page for gadget DeferredDisplay, copy-pasted the content from LargerGallery request and adjusted for the other gadget. This means the caption is the same: Necessary update after change in code base.

After saving I was very surprised that this section was already displayed as being marked as topic subscribed. So, I opened Special:TopicSubscriptions only to see the subscription for the section in LargerGallery, nothing for the one in DeferredDisplay. And after I unsubscribed in DeferredDisplay (hit the button to the right of the caption) the subscription for LargerGallery was removed.

Of course, I would expect that this does not happen and both topics are distinguished despite the identical caption.

Event Timeline

This is a known limitation of DiscussionTools:

If the title, username and timestamp are identical, the topics are indistinguishable.

Thank you, @Esanders. That’s quite unpleasing, but because it’s documented, it means this ticket has to be closed, then.

But why are the different page names or probably better there internal page id numbers not taken into consideration?

But why are the different page names or probably better there internal page id numbers not taken into consideration?

A few reasons:

  • Comments & threads can appear on multiple pages due to template transclusion
  • Comments & threads are eventually archived and moved to another page

Having an identifier that is independent of the page title allows features that depends on it to not break when comments are archived, or viewed from the "wrong" transclusion level.

An option to work around this might be to change the timestamp format of signatures to include seconds, or add some other hidden identifier, but so far we have found this to be a relative rare edge case.

some other hidden identifier

The revision ID would be a perfect identifier. However, it would spam the talk page wikitext, which it may not be worth for such an edge case. (MassMessage could make use of it, though, as mass messages are likely to have conflicts.)

A few reasons:

Thank you for your answer.