improvement: Add support for field names in idenitity constraints (#478)

lib/data_layer.ex

@@ -2310,7 +2310,7 @@ defmodule AshPostgres.DataLayer do
          %Postgrex.Error{} = error,
          stacktrace,
          {:bulk_create, fake_changeset},
-         _resource
+         resource
        ) do
     case Ecto.Adapters.Postgres.Connection.to_constraints(error, []) do
       [] ->
@@ -2319,7 +2319,7 @@ defmodule AshPostgres.DataLayer do
       constraints ->
         {:error,
          fake_changeset
-         |> constraints_to_errors(:insert, constraints)
+         |> constraints_to_errors(:insert, constraints, resource)
          |> Ash.Error.to_ash_error()}
     end
   end
@@ -2372,7 +2372,7 @@ defmodule AshPostgres.DataLayer do
     {:error, Ash.Error.to_ash_error(error, stacktrace)}
   end
 
-  defp constraints_to_errors(%{constraints: user_constraints} = changeset, action, constraints) do
+  defp constraints_to_errors(%{constraints: user_constraints} = changeset, action, constraints, resource) do
     Enum.map(constraints, fn {type, constraint} ->
       user_constraint =
         Enum.find(user_constraints, fn c ->
@@ -2387,14 +2387,25 @@ defmodule AshPostgres.DataLayer do
 
       case user_constraint do
         %{field: field, error_message: error_message, type: type, constraint: constraint} ->
-          Ash.Error.Changes.InvalidAttribute.exception(
-            field: field,
-            message: error_message,
-            private_vars: [
-              constraint: constraint,
-              constraint_type: type
-            ]
-          )
+          identities = Ash.Resource.Info.identities(resource)
+          table = AshPostgres.DataLayer.Info.table(resource)
+
+          identity = Enum.find(identities, fn identity ->
+            "#{table}_#{identity.name}_index" == constraint
+          end)
+
+          field_names = if identity, do: identity.field_names, else: [field]
+
+          Enum.map(field_names, fn field_name ->
+            Ash.Error.Changes.InvalidAttribute.exception(
+              field: field_name,
+              message: error_message,
+              private_vars: [
+                constraint: constraint,
+                constraint_type: type
+              ]
+            )
+          end)
 
         nil ->
           Ecto.ConstraintError.exception(

mix.exs

@@ -165,7 +165,7 @@ defmodule AshPostgres.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
-      {:ash, ash_version("~> 3.4 and >= 3.4.48")},
+      {:ash, ash_version("~> 3.4 and >= 3.4.64")},
       {:ash_sql, ash_sql_version("~> 0.2 and >= 0.2.43")},
       {:igniter, "~> 0.5 and >= 0.5.16", optional: true},
       {:ecto_sql, "~> 3.12"},
@@ -197,7 +197,7 @@ defmodule AshPostgres.MixProject do
         [path: "../ash", override: true]
 
       "main" ->
-        [git: "https://github.com/ash-project/ash.git"]
+        [git: "https://github.com/ash-project/ash.git", override: true]
 
       version when is_binary(version) ->
         "~> #{version}"

priv/resource_snapshots/test_repo/orgs/20250210191116.json

@@ -0,0 +1,64 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "fragment(\"gen_random_uuid()\")",
+      "generated?": false,
+      "primary_key?": true,
+      "references": null,
+      "size": null,
+      "source": "id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "name",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "primary_key?": false,
+      "references": null,
+      "size": null,
+      "source": "department",
+      "type": "text"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "1D1BA9E1E272238D80C9861CAA67C4A85F675E3B052A15F4D5AC272551B820A7",
+  "identities": [
+    {
+      "all_tenants?": false,
+      "base_filter": null,
+      "index_name": "orgs_department_index",
+      "keys": [
+        {
+          "type": "string",
+          "value": "(LOWER(department))"
+        }
+      ],
+      "name": "department",
+      "nils_distinct?": true,
+      "where": null
+    }
+  ],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.AshPostgres.TestRepo",
+  "schema": null,
+  "table": "orgs"
+}

priv/test_repo/migrations/20250210191116_migrate_resources49.exs

@@ -0,0 +1,25 @@
+defmodule AshPostgres.TestRepo.Migrations.MigrateResources49 do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    alter table(:orgs) do
+      add(:department, :text)
+    end
+
+    create(unique_index(:orgs, ["(LOWER(department))"], name: "orgs_department_index"))
+  end
+
+  def down do
+    drop_if_exists(unique_index(:orgs, ["(LOWER(department))"], name: "orgs_department_index"))
+
+    alter table(:orgs) do
+      remove(:department)
+    end
+  end
+end

test/support/resources/organization.ex

@@ -10,6 +10,8 @@ defmodule AshPostgres.Test.Organization do
   postgres do
     table("orgs")
     repo(AshPostgres.TestRepo)
+
+    calculations_to_sql(lower_department: "LOWER(department)")
   end
 
   policies do
@@ -39,6 +41,15 @@ defmodule AshPostgres.Test.Organization do
   attributes do
     uuid_primary_key(:id, writable?: true)
     attribute(:name, :string, public?: true)
+    attribute(:department, :string, public?: true)
+  end
+
+  calculations do
+    calculate(:lower_department, :string, expr(fragment("LOWER(?)", department)))
+  end
+
+  identities do
+    identity(:department, [:lower_department], field_names: [:department_slug])
   end
 
   relationships do

test/unique_identity_test.exs

@@ -1,6 +1,7 @@
 defmodule AshPostgres.Test.UniqueIdentityTest do
   use AshPostgres.RepoCase, async: false
   alias AshPostgres.Test.Post
+  alias AshPostgres.Test.Organization
 
   require Ash.Query
 
@@ -19,6 +20,19 @@ defmodule AshPostgres.Test.UniqueIdentityTest do
                  end
   end
 
+  test "unique constraint field names are property set" do
+    Organization
+    |> Ash.Changeset.for_create(:create, %{name: "Acme", department: "Sales"})
+    |> Ash.create!()
+
+    assert {:error, %Ash.Error.Invalid{errors: [invalid_attribute]}} =
+             Organization
+             |> Ash.Changeset.for_create(:create, %{name: "Acme", department: "SALES"})
+             |> Ash.create()
+
+    assert %Ash.Error.Changes.InvalidAttribute{field: :department_slug} = invalid_attribute
+  end
+
   test "a unique constraint can be used to upsert when the resource has a base filter" do
     post =
       Post