improvement: Add nulls_distinct option to CustomIndex (#221)

.formatter.exs

@@ -25,6 +25,7 @@ spark_locals_without_parens = [
   migration_ignore_attributes: 1,
   migration_types: 1,
   name: 1,
+  nulls_distinct: 1,
   on_delete: 1,
   on_update: 1,
   polymorphic?: 1,

documentation/dsls/DSL:-AshPostgres.DataLayer.md

@@ -111,8 +111,9 @@ index ["column", "column2"], unique: true, where: "thing = TRUE"
 | [`using`](#postgres-custom_indexes-index-using){: #postgres-custom_indexes-index-using } | `String.t` |  | configures the index type. |
 | [`prefix`](#postgres-custom_indexes-index-prefix){: #postgres-custom_indexes-index-prefix } | `String.t` |  | specify an optional prefix for the index. |
 | [`where`](#postgres-custom_indexes-index-where){: #postgres-custom_indexes-index-where } | `String.t` |  | specify conditions for a partial index. |
-| [`message`](#postgres-custom_indexes-index-message){: #postgres-custom_indexes-index-message } | `String.t` |  | A custom message to use for unique indexes that have been violated |
 | [`include`](#postgres-custom_indexes-index-include){: #postgres-custom_indexes-index-include } | `list(String.t)` |  | specify fields for a covering index. This is not supported by all databases. For more information on PostgreSQL support, please read the official docs. |
+| [`nulls_distinct`](#postgres-custom_indexes-index-nulls_distinct){: #postgres-custom_indexes-index-nulls_distinct } | `boolean` |  | specify whether null values should be considered distinct for a unique index. |
+| [`message`](#postgres-custom_indexes-index-message){: #postgres-custom_indexes-index-message } | `String.t` |  | A custom message to use for unique indexes that have been violated |
 | [`all_tenants?`](#postgres-custom_indexes-index-all_tenants?){: #postgres-custom_indexes-index-all_tenants? } | `boolean` | `false` | Whether or not the index should factor in the multitenancy attribute or not. |
 
 

lib/custom_index.ex

@@ -11,6 +11,7 @@ defmodule AshPostgres.CustomIndex do
     :prefix,
     :where,
     :include,
+    :nulls_distinct,
     :message,
     :all_tenants?
   ]
@@ -54,15 +55,20 @@ defmodule AshPostgres.CustomIndex do
       type: :string,
       doc: "specify conditions for a partial index."
     ],
-    message: [
-      type: :string,
-      doc: "A custom message to use for unique indexes that have been violated"
-    ],
     include: [
       type: {:list, :string},
       doc:
         "specify fields for a covering index. This is not supported by all databases. For more information on PostgreSQL support, please read the official docs."
     ],
+    nulls_distinct: [
+      type: :boolean,
+      doc: "specify whether null values should be considered distinct for a unique index.",
+      default: false
+    ],
+    message: [
+      type: :string,
+      doc: "A custom message to use for unique indexes that have been violated"
+    ],
     all_tenants?: [
       type: :boolean,
       default: false,

lib/migration_generator/migration_generator.ex

@@ -2988,6 +2988,7 @@ defmodule AshPostgres.MigrationGenerator do
         end)
       end)
       |> Map.put_new(:include, [])
+      |> Map.put_new(:nulls_distinct, false)
       |> Map.put_new(:message, nil)
       |> Map.put_new(:all_tenants?, false)
     end)

lib/migration_generator/operation.ex

@@ -908,6 +908,7 @@ defmodule AshPostgres.MigrationGenerator.Operation do
           option(:prefix, index.prefix),
           option(:where, index.where),
           option(:include, index.include),
+          option(:nulls_distinct, index.nulls_distinct),
           option(:prefix, schema)
         ])
 

test/migration_generator_test.exs

@@ -298,6 +298,51 @@ defmodule AshPostgres.MigrationGeneratorTest do
     end
   end
 
+  describe "custom_indexes with `null_distinct: true`" do
+    setup do
+      on_exit(fn ->
+        File.rm_rf!("test_snapshots_path")
+        File.rm_rf!("test_migration_path")
+      end)
+
+      defposts do
+        postgres do
+          custom_indexes do
+            index([:uniq_one], nulls_distinct: true)
+            index([:uniq_two], nulls_distinct: false)
+            index([:uniq_custom_one])
+          end
+        end
+
+        attributes do
+          uuid_primary_key(:id)
+          attribute(:title, :string)
+        end
+      end
+
+      defapi([Post])
+      Mix.shell(Mix.Shell.Process)
+
+      AshPostgres.MigrationGenerator.generate(Api,
+        snapshot_path: "test_snapshots_path",
+        migration_path: "test_migration_path",
+        quiet: true,
+        format: false
+      )
+    end
+
+    test "it adds nulls_distinct option to create index migration" do
+      assert [custom_index_migration] =
+               Enum.sort(Path.wildcard("test_migration_path/**/*_migrate_resources*.exs"))
+
+      file = File.read!(custom_index_migration)
+
+      assert file =~ ~S<create index(:posts, [:uniq_one], nulls_distinct: true)>
+      assert file =~ ~S<create index(:posts, [:uniq_two])>
+      assert file =~ ~S<create index(:posts, [:uniq_custom_one])>
+    end
+  end
+
   describe "creating follow up migrations with a schema" do
     setup do
       on_exit(fn ->