Single state struct for a MishkaGervaz form LiveView.

All per-request form state lives on t/0. Instead of scattering values across LiveView assigns, every consumer of the form pipeline reads from and writes to this struct, giving:

• One clearly-typed shape (t/0 and t:Static.t/0).
• One place to thread updates (update/2).
• One source of truth for events, the renderer, and tests.

Performance split

State is partitioned into two halves:

• static (t:Static.t/0) — configuration that never changes after init/3. Same struct reference for the lifetime of the form, which lets LiveView skip re-rendering nodes that depend only on it.
• Dynamic fields — user-interaction state (form values, current step, relation options, errors, …) that drive re-renders.

Sub-builders

init/3 composes its work from five overridable sub-builder modules. The DSL (state do … end) can override any of them per-resource, and the use macro accepts the same set as compile-time options.

• MishkaGervaz.Form.Web.State.FieldBuilder — resolved field configs.
• MishkaGervaz.Form.Web.State.GroupBuilder — group layout.
• MishkaGervaz.Form.Web.State.StepBuilder — wizard / tabs step plan.
• MishkaGervaz.Form.Web.State.Presentation — UI adapter, template, theme, features, debounce.
• MishkaGervaz.Form.Web.State.Access — master gate, action mapping, preload selection.

Override patterns

Override the entire state module:

defmodule MyApp.Form.State do
  use MishkaGervaz.Form.Web.State

  def init(id, resource, user) do
    state = super(id, resource, user)
    MishkaGervaz.Form.Web.State.update(state, mode: :update)
  end
end

Use update/2 (or struct/2) to mutate fields — the struct shape is fixed and there is no :custom_field. To carry your own data, attach it to state.static.config (read-only, set at build time) or stage it on state.field_values.

Override specific sub-builders:

defmodule MyApp.Form.State do
  use MishkaGervaz.Form.Web.State,
    field: MyApp.Form.FieldBuilder,
    group: MyApp.Form.GroupBuilder
end

Or override via DSL:

mishka_gervaz do
  form do
    state do
      field MyApp.Form.FieldBuilder
      group MyApp.Form.GroupBuilder
    end
  end
end

Override entire state module via DSL:

mishka_gervaz do
  form do
    state module: MyApp.Form.CustomState
  end
end

See MishkaGervaz.Form.Web.State.Helpers (shared utilities exposed to the macro and to user overrides), MishkaGervaz.Form.Web.Live, MishkaGervaz.Form.Web.Events, MishkaGervaz.Form.Web.DataLoader, MishkaGervaz.Form.Behaviours.Template, and the table-side counterpart MishkaGervaz.Table.Web.State.