The most notable change here is that when you are adding
subscribers to a stream as part of creating the stream,
you can now use the same essential pill-based UI for
adding users as we do when you edit subscribers for an
existing stream.
We don't try to exactly mimic the edit-stream UI or
implementation, since when you are adding subscribers
during create-stream, we are just updating a list in
memory, whereas in the edit-stream UI, we immediately
send info to the server.
Fixes#20499
For our Subscribers tab we want to enclose our
add-subscriber widget in a form for now, and we
continue to do so, but now we have the form tag
getting created in the parent template, not the
child.
Here is why:
We want to re-use our add-subscriber widget in an
upcoming commit for when you create streams.
In our create-stream UI, there is already an outer
<form>...</form> section of the HTML for the entire
process of creating a stream.
HTML does not yet you nest forms, and even though
browsers just silently ignore an inner form, we won't
want to create semantically incorrect HTML.
Therefore, we want the child template not to have
the form tags around them.
It's possible that we don't really even want to
enclose the input-pill widget and Add button inside
a form for the Subscribers tab, but tweaking that
for now is too risky. (We don't really take advantage
of the form tag in any meaningful way, since we
don't directly submit form data to the server, and
we can't use a single submit handler for the Enter
key and Add button due to some magic in our input
pills.)
You don't start auto-completing user groups with an @,
so the previous placeholder text made no sense.
There might be a better way to do autocomplete in
these add-subscriber input pills, but that is beyond
the scope of my current efforts.
Steve Howell