improvement: add some atomic implementations

lib/ash/changeset/changeset.ex

@@ -567,30 +567,42 @@ defmodule Ash.Changeset do
         end
 
       %{validation: {module, validation_opts}, where: where}, changeset ->
-        with {:atomic, fields, condition_expr, error_expr} <-
-               module.atomic(changeset, validation_opts),
-             {:changing?, true} <-
-               {:changing?, Enum.any?(fields, &changing_attribute?(changeset, &1))},
-             {:atomic, condition} <- atomic_condition(where, changeset) do
-          case condition do
-            true ->
-              {:cont, validate_atomically(changeset, condition_expr, error_expr)}
+        case List.wrap(module.atomic(changeset, validation_opts)) do
+          [{:atomic, _, _, _} | _] = atomics ->
+            Enum.reduce_while(atomics, changeset, fn
+              {:atomic, fields, condition_expr, error_expr}, changeset ->
+                with {:changing?, true} <-
+                       {:changing?,
+                        fields == :* || Enum.any?(fields, &changing_attribute?(changeset, &1))},
+                     {:atomic, condition} <- atomic_condition(where, changeset) do
+                  case condition do
+                    true ->
+                      {:cont, validate_atomically(changeset, condition_expr, error_expr)}
 
-            false ->
-              {:cont, changeset}
+                    false ->
+                      {:cont, changeset}
 
-            condition ->
-              condition_expr =
-                Ash.Expr.expr(^condition and condition_expr)
+                    condition ->
+                      condition_expr =
+                        Ash.Expr.expr(^condition and condition_expr)
 
-              {:cont, validate_atomically(changeset, condition_expr, error_expr)}
-          end
-        else
-          :not_atomic ->
-            {:halt, :not_atomic}
+                      {:cont, validate_atomically(changeset, condition_expr, error_expr)}
+                  end
+                else
+                  {:changing?, false} ->
+                    {:cont, changeset}
 
-          {:changing?, false} ->
-            {:cont, changeset}
+                  :not_atomic ->
+                    {:halt, :not_atomic}
+                end
+            end)
+            |> case do
+              :not_atomic -> {:halt, :not_atomic}
+              changeset -> {:cont, changeset}
+            end
+
+          [value] ->
+            {:halt, value}
         end
     end)
   end
@@ -630,13 +642,24 @@ defmodule Ash.Changeset do
   Gets a reference to a field, or the current atomic update expression of that field.
   """
   def atomic_ref(changeset, field) do
-    if base_value = changeset.atomics[field] do
-      %{type: type, constraints: constraints} =
-        Ash.Resource.Info.attribute(changeset.resource, field)
+    case Keyword.fetch(changeset.atomics, field) do
+      {:ok, atomic} ->
+        %{type: type, constraints: constraints} =
+          Ash.Resource.Info.attribute(changeset.resource, field)
 
-      Ash.Expr.expr(type(^base_value, ^type, ^constraints))
-    else
-      Ash.Expr.expr(ref(^field))
+        Ash.Expr.expr(type(^atomic, ^type, ^constraints))
+
+      :error ->
+        case Map.fetch(changeset.attributes, field) do
+          {:ok, new_value} ->
+            %{type: type, constraints: constraints} =
+              Ash.Resource.Info.attribute(changeset.resource, field)
+
+            Ash.Expr.expr(type(^new_value, ^type, ^constraints))
+
+          :error ->
+            Ash.Expr.expr(ref(^field))
+        end
     end
   end
 

lib/ash/resource/validation.ex

@@ -48,8 +48,12 @@ defmodule Ash.Resource.Validation do
   @callback atomic?() :: boolean
   @callback atomic(changeset :: Ash.Changeset.t(), opts :: Keyword.t()) ::
               :ok
-              | {:atomic, involved_fields :: list(atom), condition_expr :: Ash.Expr.t(),
+              | {:atomic, involved_fields :: list(atom) | :*, condition_expr :: Ash.Expr.t(),
                  error_expr :: Ash.Expr.t()}
+              | [
+                  {:atomic, involved_fields :: list(atom) | :*, condition_expr :: Ash.Expr.t(),
+                   error_expr :: Ash.Expr.t()}
+                ]
               | :not_atomic
               | {:error, term()}
 

lib/ash/resource/validation/action_is.ex

@@ -15,6 +15,11 @@ defmodule Ash.Resource.Validation.ActionIs do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    validate(changeset, opts)
+  end
+
   @impl true
   def describe(opts) do
     [message: "must be %{action}", vars: %{action: opts[:action]}]

lib/ash/resource/validation/argument_does_not_equal.ex

@@ -43,6 +43,11 @@ defmodule Ash.Resource.Validation.ArgumentDoesNotEqual do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    validate(changeset, opts)
+  end
+
   @impl true
   def describe(opts) do
     [

lib/ash/resource/validation/argument_equals.ex

@@ -42,6 +42,11 @@ defmodule Ash.Resource.Validation.ArgumentEquals do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    validate(changeset, opts)
+  end
+
   @impl true
   def describe(opts) do
     [

lib/ash/resource/validation/argument_in.ex

@@ -42,6 +42,11 @@ defmodule Ash.Resource.Validation.ArgumentIn do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    validate(changeset, opts)
+  end
+
   @impl true
   def describe(opts) do
     [

lib/ash/resource/validation/attribute_in.ex

@@ -16,6 +16,7 @@ defmodule Ash.Resource.Validation.AttributeIn do
 
   use Ash.Resource.Validation
   alias Ash.Error.Changes.InvalidAttribute
+  require Ash.Expr
 
   @impl true
   def init(opts) do
@@ -42,11 +43,26 @@ defmodule Ash.Resource.Validation.AttributeIn do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    field_value = Ash.Changeset.atomic_ref(changeset, opts[:attribute])
+
+    {:atomic, [opts[:attribute]], Ash.Expr.expr(^field_value in ^opts[:list]),
+     Ash.Expr.expr(
+       error(^InvalidAttribute, %{
+         field: ^opts[:attribute],
+         value: ^field_value,
+         message: "must be in %{list}",
+         vars: %{field: ^opts[:attribute], list: ^opts[:list]}
+       })
+     )}
+  end
+
   @impl true
   def describe(opts) do
     [
-      message: "must equal %{value}",
-      vars: [field: opts[:attribute], value: opts[:value]]
+      message: "must be in %{list}",
+      vars: [field: opts[:attribute], list: opts[:list]]
     ]
   end
 end

lib/ash/resource/validation/changing.ex

@@ -4,6 +4,7 @@ defmodule Ash.Resource.Validation.Changing do
   use Ash.Resource.Validation
 
   alias Ash.Error.Changes.InvalidAttribute
+  require Ash.Expr
 
   @opt_schema [
     field: [
@@ -51,6 +52,22 @@ defmodule Ash.Resource.Validation.Changing do
     end
   end
 
+  @impl true
+  def atomic(changeset, opts) do
+    new_value = Ash.Changeset.atomic_ref(changeset, opts[:field])
+    old_value = Ash.Expr.expr(ref(^opts[:field]))
+
+    {:atomic, [opts[:field]], Ash.Expr.expr(^new_value != ^old_value),
+     Ash.Expr.expr(
+       error(^InvalidAttribute, %{
+         field: ^opts[:field],
+         value: ^new_value,
+         message: "must be changing",
+         vars: %{field: ^opts[:field]}
+       })
+     )}
+  end
+
   @impl true
   def describe(_opts) do
     [

lib/ash/resource/validation/compare.ex

@@ -4,6 +4,7 @@ defmodule Ash.Resource.Validation.Compare do
   use Ash.Resource.Validation
 
   alias Ash.Error.Changes.InvalidAttribute
+  require Ash.Expr
 
   @impl true
   def init(opts) do
@@ -67,6 +68,66 @@ defmodule Ash.Resource.Validation.Compare do
     end
   end
 
+  def atomic(changeset, opts) do
+    case Ash.Changeset.fetch_argument(changeset, opts[:attribute]) do
+      :error ->
+        ref = Ash.Changeset.atomic_ref(changeset, opts[:attribute])
+
+        opts
+        |> Keyword.take([
+          :greater_than,
+          :less_than,
+          :greater_than_or_equal_to,
+          :less_than_or_equal_to
+        ])
+        |> Enum.map(fn
+          {:greater_than, value} ->
+            {:atomic, [opts[:attribute]], Ash.Expr.expr(^ref <= ^value),
+             Ash.Expr.expr(
+               error(^InvalidAttribute, %{
+                 field: ^opts[:attribute],
+                 value: ^ref,
+                 message: "must be greater than %{greater_than}",
+                 vars: %{field: ^opts[:attribute], greater_than: ^value}
+               })
+             )}
+
+          {:less_than, value} ->
+            {:atomic, [opts[:attribute]], Ash.Expr.expr(^ref >= ^value),
+             Ash.Expr.expr(
+               error(^InvalidAttribute, %{
+                 field: ^opts[:attribute],
+                 value: ^ref,
+                 message: "must be less than %{less_than}",
+                 vars: %{field: ^opts[:attribute], less_than: ^value}
+               })
+             )}
+
+          {:greater_than_or_equal_to, value} ->
+            {:atomic, [opts[:attribute]], Ash.Expr.expr(^ref < ^value),
+             Ash.Expr.expr(
+               error(^InvalidAttribute, %{
+                 field: ^opts[:attribute],
+                 value: ^ref,
+                 message: "must be greater than or equal to %{greater_than_or_equal_to}",
+                 vars: %{field: ^opts[:attribute], greater_than_or_equal_to: ^value}
+               })
+             )}
+
+          {:less_than_or_equal_to, value} ->
+            {:atomic, [opts[:attribute]], Ash.Expr.expr(^ref > ^value),
+             Ash.Expr.expr(
+               error(^InvalidAttribute, %{
+                 field: ^opts[:attribute],
+                 value: ^ref,
+                 message: "must be less than or equal to %{less_than_or_equal_to}",
+                 vars: %{field: ^opts[:attribute], less_than_or_equal_to: ^value}
+               })
+             )}
+        end)
+    end
+  end
+
   @impl true
   def describe(opts) do
     [

test/actions/update_test.exs

@@ -105,6 +105,7 @@ defmodule Ash.Test.Actions.UpdateTest do
         accept([:name])
 
         validate attribute_equals(:name, "fred")
+        validate compare(:score, greater_than_or_equal_to: 0, less_than_or_equal_to: 10)
       end
 
       update :duplicate_name do
@@ -128,6 +129,7 @@ defmodule Ash.Test.Actions.UpdateTest do
       uuid_primary_key :id
       attribute :name, :string
       attribute :bio, :string
+      attribute :score, :integer
     end
 
     relationships do