fix: don't treat an already-run migration as unrecognised

piccolo/apps/migrations/commands/forwards.py

@@ -31,6 +31,11 @@ async def run_migrations(self, app_config: AppConfig) -> MigrationResult:
             app_name=app_config.app_name
         )
 
+        if self.migration_id in already_ran:
+            message = f"🏁 Migration {self.migration_id} has already been run"
+            print(message)
+            return MigrationResult(success=True, message=message)
+
         migration_modules: dict[str, MigrationModule] = (
             self.get_migration_modules(
                 app_config.resolved_migrations_folder_path

tests/apps/migrations/commands/test_forwards_backwards.py

@@ -9,7 +9,7 @@
 from piccolo.apps.migrations.commands.forwards import forwards
 from piccolo.apps.migrations.tables import Migration
 from piccolo.utils.sync import run_sync
-from tests.base import engines_only
+from tests.base import AsyncMock, engines_only
 from tests.example_apps.music.tables import (
     Band,
     Concert,
@@ -141,6 +141,35 @@ def test_forwards_unknown_migration(self, print_: MagicMock):
             in print_.mock_calls
         )
 
+    @patch("piccolo.apps.migrations.commands.forwards.print")
+    @patch(
+        "piccolo.apps.migrations.commands.forwards.Migration.get_migrations_which_ran",  # noqa: E501
+        new_callable=AsyncMock,
+    )
+    def test_already_ran(
+        self,
+        get_migrations_which_ran: MagicMock,
+        print_: MagicMock,
+    ):
+        """
+        When a specific migration ID has already run, but there are later
+        migrations which haven't, then the command should succeed rather than
+        reporting the migration as unrecognised.
+
+        https://github.com/piccolo-orm/piccolo/issues/1359
+
+        """
+        migration_id = "2020-12-17T18:44:30"
+
+        get_migrations_which_ran.return_value = [migration_id]
+
+        run_sync(forwards(app_name="music", migration_id=migration_id))
+
+        self.assertIn(
+            call(f"🏁 Migration {migration_id} has already been run"),
+            print_.mock_calls,
+        )
+
     @patch("piccolo.apps.migrations.commands.backwards.print")
     def test_backwards_unknown_migration(self, print_: MagicMock):
         """