unread: Make the n key respect the left sidebar filter.

[jai2201]

When going to the next unread message we should restrict
the streams according to the stream filter, if it is filled in.
And similarly for the topic filter, if you're currently
viewing "more topics".

So, modified the algorithm to iterate through the unread
actively-filtered topics first, then the other unread
topics in the stream, and then all the unfiltered
topics of other streams (no filters applied for any of those).

Fixes #21437.

Screenshots and screen captures:

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[zulipbot]

Hello @zulip/server-sidebars members, this pull request was labeled with the "area: left-sidebar" label, so you may want to check it out!

[jai2201]

@sayamsamal , Can you please review this PR.

[jai2201]

@alya can you please take a look at this.

[alya]

@sayamsamal please review this PR when you get a chance. Thanks!

[alya]

Since it looks like @sayamsamal is not currently available, @punchagan I wonder if you'd be up for doing an initial review on this PR?

[sayamsamal]

@alya Sorry for the delayed heads up, I have actually completed walking through and reviewing this PR.

Here are my observations,

• While using the topic filter

1. The 'n' key first goes through all the filtered list of topics.
2. Then it iterates over all the unread messages, irrespective of the topic filter applied.

• While using the stream filter

1. The 'n' key first goes through all the topics of the filtered stream(s)
2. Once all the unread messages from the filtered stream(s) are read, it stops iteration even if other unread messages exist.

From these observations, and having gone through the CZO and the issue, do we want the topic filter to reach the second step, where it iterates over all the unread messages, or should it stop once the filtered list of unread messages are iterated through?

FYI, @jai2201

[alya]

Hm, good question!

I don't have a super clear intuition on this, other than that we should be consistent between stream and topic filters. :)

@jai2201 would you be up for asking what folks think in a #design conversation?

[alya]

I also think either approach would be an improvement over the current state (as long as streams/topics are consistent), so if one is much easier to implement, we could start with that.

[zulipbot]

Heads up @jai2201, we just merged some commits that conflict with the changes you made in this pull request! You can review this repository's recent commits to see where the conflicts occur. Please rebase your feature branch against the upstream/main branch and resolve your pull request's merge conflicts accordingly.