Filter form missing `id` triggers LiveView `missing_form_id` warning (no form recovery)

[mbaertschi]

Summary

The filter/search <form> rendered by Cinder.FilterManager has no id attribute. On phoenix_live_view 1.1+ this triggers the new missing_form_id diagnostic, and more importantly it means LiveView cannot perform form recovery for the filter form after a disconnect or crash.

Versions

• cinder 0.15.0 (latest)
• phoenix_live_view 1.2.1

Warning

Running any test that mounts a LiveView containing a <Cinder.collection> prints:

warning: Detected a form with phx-change but missing id:

    <form phx-change="filter_change" phx-submit="filter_change" phx-target="1"></form>

Without an id, LiveView will not be able to perform form recovery,
for more information see:
https://hexdocs.pm/phoenix_live_view/form-bindings.html#recovery-following-crashes-or-disconnects

Cause

lib/cinder/filter_manager.ex renders the filter form without an id in both branches:

• render_filter_controls_with_slot/2 — line 75
• render_filter_controls_default/1 — line 110

<form phx-change="filter_change" phx-submit="filter_change" phx-target={@target}>

Suggested fix

@table_id is already in scope in this module (e.g. it's used at line 109 for id={"#{@table_id}-filter-body"}), so the form can derive a stable, unique id from it:

<form id={"#{@table_id}-filter-form"} phx-change="filter_change" phx-submit="filter_change" phx-target={@target}>

Only one of the two branches renders per table, so a single "#{@table_id}-filter-form" scheme stays unique.

[sevenseacat]

Fixed by #190 :)