From 57ec307420e1e1c826d07ea8f923504058ec4657 Mon Sep 17 00:00:00 2001
From: marco Dell'Olio <dellolio.marco@gmail.com>
Date: Sun, 29 Jun 2025 20:47:10 -0400
Subject: [PATCH] raise error if the constraint is created on a field that
 doesn't exist

---
 .../migration_generator.ex                    |  6 ++++
 test/migration_generator_test.exs             | 31 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/lib/migration_generator/migration_generator.ex b/lib/migration_generator/migration_generator.ex
index a5984a67..8a7df6e8 100644
--- a/lib/migration_generator/migration_generator.ex
+++ b/lib/migration_generator/migration_generator.ex
@@ -3125,6 +3125,12 @@ defmodule AshPostgres.MigrationGenerator do
             resource
             |> Ash.Resource.Info.attribute(attribute)
 
+          if is_nil(attr) do
+            raise """
+            Cannot create the check constraint '#{constraint.name}', the attribute '#{attribute}' does not exist in the resource '#{resource}' or is nil.
+            """
+          end
+
           attr.source || attr.name
         end)
 
diff --git a/test/migration_generator_test.exs b/test/migration_generator_test.exs
index e284e847..a315e13f 100644
--- a/test/migration_generator_test.exs
+++ b/test/migration_generator_test.exs
@@ -2425,6 +2425,37 @@ defmodule AshPostgres.MigrationGeneratorTest do
       assert File.read!(file) =~
                ~S[drop_if_exists constraint(:posts, :price_must_be_positive)]
     end
+
+    test "raise an error if the attribute does not exist or is nil" do
+      defposts do
+        attributes do
+          uuid_primary_key(:id)
+          attribute(:price, :integer, public?: true)
+        end
+
+        postgres do
+          check_constraints do
+            check_constraint(:whatever, "price_must_be_positive", check: ~S["price" > 0])
+          end
+        end
+      end
+
+      defdomain([Post])
+
+      error =
+        assert_raise RuntimeError, fn ->
+          AshPostgres.MigrationGenerator.generate(Domain,
+            snapshot_path: "test_snapshots_path",
+            migration_path: "test_migration_path",
+            quiet: true,
+            format: false,
+            auto_name: true
+          )
+        end
+
+      assert error.message =~
+               "Cannot create the check constraint 'price_must_be_positive', the attribute 'whatever' does not exist in the resource 'Elixir.Post' or is nil."
+    end
   end
 
   describe "polymorphic resources" do