feat: Add check_migrated option to migration generator (#40) (#43)

.formatter.exs

@@ -12,6 +12,7 @@ locals_without_parens = [
 ]
 
 [
+  import_deps: [:ash],
   inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
   locals_without_parens: locals_without_parens,
   export: [

lib/migration_generator/migration_generator.ex

@@ -16,11 +16,20 @@ defmodule AshPostgres.MigrationGenerator do
             quiet: false,
             format: true,
             dry_run: false,
+            check_generated: false,
             drop_columns: false
 
   def generate(apis, opts \\ []) do
     apis = List.wrap(apis)
-    opts = struct(__MODULE__, opts)
+
+    opts =
+      case struct(__MODULE__, opts) do
+        %{check_generated: true} = opts ->
+          %{opts | dry_run: true}
+
+        opts ->
+          opts
+      end
 
     {tenant_snapshots, snapshots} =
       apis
@@ -68,6 +77,8 @@ defmodule AshPostgres.MigrationGenerator do
           :ok
 
         operations ->
+          if opts.check_generated, do: exit({:shutdown, 1})
+
           operations
           |> sort_operations()
           |> streamline()

lib/mix/tasks/ash_postgres.generate_migrations.ex

@@ -16,6 +16,7 @@ defmodule Mix.Tasks.AshPostgres.GenerateMigrations do
   * `quiet` - messages for file creations will not be printed
   * `no_format` - files that are created will not be formatted with the code formatter
   * `dry_run` - no files are created, instead the new migration is printed
+  * `check_migrated` - no files are created, returns an exit(1) code if the current snapshots and resources don't fit
 
   #### Snapshots
 
@@ -77,6 +78,7 @@ defmodule Mix.Tasks.AshPostgres.GenerateMigrations do
           quiet: :boolean,
           no_format: :boolean,
           dry_run: :boolean,
+          check_migrated: :boolean,
           drop_columns: :boolean
         ]
       )

test/migration_generator_test.exs

@@ -388,4 +388,32 @@ defmodule AshPostgres.MigrationGeneratorTest do
                ~S[add :views, :integer]
     end
   end
+
+  describe "--check_migrated option" do
+    setup do
+      defposts do
+        attributes do
+          uuid_primary_key :id
+          attribute(:title, :string)
+        end
+      end
+
+      defapi([Post])
+
+      [api: Api]
+    end
+
+    test "returns code(1) if snapshots and resources don't fit", %{api: api} do
+      assert catch_exit(
+               AshPostgres.MigrationGenerator.generate(api,
+                 snapshot_path: "test_snapshot_path",
+                 migration_path: "test_migration_path",
+                 check_generated: true
+               )
+             ) == {:shutdown, 1}
+
+      refute File.exists?(Path.wildcard("test_migration_path2/**/*_migrate_resources*.exs"))
+      refute File.exists?(Path.wildcard("test_snapshots_path2/test_repo/posts/*.json"))
+    end
+  end
 end