improvement: make default page type configurable, defaulting to :offset

The getting started guide and ash installer set it to `:keyset`

closes #1413

documentation/tutorials/get-started.md

@@ -253,7 +253,9 @@ import Config
 
 config :helpdesk, :ash_domains, [Helpdesk.Support]
 
-config :ash, :include_embedded_source_by_default?, true
+config :ash,
+  include_embedded_source_by_default?: false,
+  default_page_type: :keyset
 ```
 
 ### Try our first resource out

lib/ash/actions/read/read.ex

@@ -1737,7 +1737,13 @@ defmodule Ash.Actions.Read do
           Ash.Page.Keyset.new(data, count, sort, original_query, more?, opts)
 
         action.pagination.offset? && action.pagination.keyset? ->
+          case Application.get_env(:ash, :default_page_type, :offset) do
+            :keyset ->
+              Ash.Page.Keyset.new(data, count, sort, original_query, more?, opts)
+
+            :offset ->
               Ash.Page.Offset.new(data, count, original_query, more?, opts)
+          end
 
         action.pagination.offset? ->
           Ash.Page.Offset.new(data, count, original_query, more?, opts)

lib/ash/resource/dsl.ex

@@ -1498,7 +1498,6 @@ defmodule Ash.Resource.Dsl do
     Ash.Resource.Verifiers.VerifyIdentityFields,
     Ash.Resource.Verifiers.EnsureAggregateFieldIsAttributeOrCalculation,
     Ash.Resource.Verifiers.ValidateRelationshipAttributes,
-    Ash.Resource.Verifiers.CountableActions,
     Ash.Resource.Verifiers.NoReservedFieldNames,
     Ash.Resource.Verifiers.ValidateAccept,
     Ash.Resource.Verifiers.ValidateActionTypesSupported,

lib/ash/resource/verifiers/countable_actions.ex

@@ -1,37 +0,0 @@
-defmodule Ash.Resource.Verifiers.CountableActions do
-  @moduledoc """
-  Ensures that countable paginated actions do not exist for resources that are not countable
-  """
-  use Spark.Dsl.Verifier
-
-  alias Spark.Dsl.Verifier
-
-  # sobelow_skip ["DOS.BinToAtom"]
-  def verify(dsl_state) do
-    dsl_state
-    |> Verifier.get_entities([:actions])
-    |> Enum.filter(fn action ->
-      action.type == :read && action.pagination && action.pagination.countable
-    end)
-    |> case do
-      [] ->
-        :ok
-
-      [action | _] ->
-        data_layer = Verifier.get_persisted(dsl_state, :data_layer)
-        resource = Verifier.get_persisted(dsl_state, :module)
-
-        if data_layer && data_layer.can?(resource, {:query_aggregate, :count}) do
-          :ok
-        else
-          {:error,
-           Spark.Error.DslError.exception(
-             module: resource,
-             path: [:actions, action.name],
-             message:
-               "Action cannot be countable, as the datalayer does not support counting queries"
-           )}
-        end
-    end
-  end
-end

lib/mix/tasks/install/ash.install.ex

@@ -57,7 +57,13 @@ defmodule Mix.Tasks.Ash.Install do
       "config.exs",
       :ash,
       [:include_embedded_source_by_default?],
-      true
+      false
+    )
+    |> Igniter.Project.Config.configure(
+      "config.exs",
+      :ash,
+      [:default_page_type],
+      :keyset
     )
     |> then(fn igniter ->
       if "--example" in argv do