Support drag and drop around spaces

[t3chguy]

Possible features:

• Reordering rooms and spaces
• Adding rooms/spaces to spaces

[robintown]

Depending on two different versions of react-beautiful-dnd is always an option, right? Apart from bundle size concerns

[t3chguy]

Whilst yes webpack and npm support dependency aliasing for this purpose, there is 0 guarantee from the lib that it supports this.

It might register globals which conflict, I think the time wasted debugging issues with a dnd library is better spent on other things and dnd can come later.

[daniellekirkwood]

I'm going to remove the Needs-Product label as it would be great to have a drag&drop functionality in the app.

Ideally;

• Subspaces can be drag&drop to move the ordering in the left panel (similarly to spaces).

• Question: Can subspaces be drag&drop to different Spaces? Should we do that Design, can we do that Engineering?

• Rooms can be drag&drop into Spaces or subspaces.

[ShadowJonathan]

Additional questions;

• If you drag a subspace between two spaces you own, would they "copy", or "move"?
• Similarly, if you drag a subspace from a non-owned space to an owned one, would they unambiguously copy?
• What about dragging a subspace from a space to the main bar? Would it be "pinned" in the sidebar? (Would this be "move" or "copy" as well?) (out of scope)

[t3chguy]

Keep in mind sometimes permissions might make it so you cannot move as you may not have the required permission to remove it from the "from" space.

What about dragging a subspace from a space to the main bar? Would it be "pinned" in the sidebar? (Would this be "move" or "copy" as well?)

This is out of scope as it'd require spec work.

[noantiq]

Hi! after opening an issue for dragging rooms into spaces (#22105) I was pointed here. I missed that a comment in this issue already reflects the use case since the issue title led me believe that this is only about re-ordering :D Maybe it would help to change the title or description of this issue accordingly?

[Reinachan]

Just adding that there is a spec for space maintainers to decide the room order in Matrix, m.space.child -> content -> order I'd suggest using that for specifying the order rooms appear in.
https://spec.matrix.org/v1.3/client-server-api/#ordering-1