Revert "fix: when validating, use empty starting point for forms"

This reverts commit a658a8085b.

lib/ash_phoenix/form/form.ex

@@ -847,7 +847,7 @@ defmodule AshPhoenix.Form do
                 end
 
               new_forms =
-                Enum.reduce(form_params, %{}, fn {index, params}, forms ->
+                Enum.reduce(form_params, forms, fn {index, params}, forms ->
                   case Enum.find(form.forms[key] || [], &matcher.(&1, params, form, key, index)) do
                     nil ->
                       create_action =
@@ -1516,6 +1516,29 @@ defmodule AshPhoenix.Form do
     |> Phoenix.HTML.Form.input_value(field)
   end
 
+  @doc """
+  Toggles the form to be ignored or not ignored.
+
+  To set this manually in an html form, use the field `:_ignored` and set it
+  to the string "true". Any other value will not result in the form being ignored.
+  """
+  @spec ignore(t()) :: t()
+  def ignore(form) do
+    if ignored?(form) do
+      %{form | params: Map.delete(form.params, "_ignore")}
+    else
+      %{form | params: Map.put(form.params, "_ignore", "true")}
+    end
+  end
+
+  @doc """
+  Returns true if the form is ignored
+  """
+  @spec ignored?(t()) :: boolean
+  def ignored?(form) do
+    form.params["_ignore"] == "true"
+  end
+
   @doc """
   Returns the parameters from the form that would be submitted to the action.
 
@@ -1534,6 +1557,9 @@ defmodule AshPhoenix.Form do
     only_touched? = Keyword.get(opts, :only_touched?, true)
     filter = opts[:filter] || fn _ -> true end
 
+    if form.params["_hidden"] do
+      raise "Cannot hide the top level form"
+    else
       form_keys =
         form.form_keys
         |> Keyword.keys()
@@ -1552,7 +1578,8 @@ defmodule AshPhoenix.Form do
         if hidden? do
           hidden = hidden_fields(form)
 
-        hidden_stringified = hidden |> Map.new(fn {field, value} -> {to_string(field), value} end)
+          hidden_stringified =
+            hidden |> Map.new(fn {field, value} -> {to_string(field), value} end)
 
           Map.merge(hidden_stringified, params)
         else
@@ -1660,6 +1687,7 @@ defmodule AshPhoenix.Form do
         with_set_params
       end
     end
+  end
 
   defp only_touched(form_keys, true, form) do
     Enum.filter(form_keys, fn {key, _} ->