Astronomer - Apache Airflow 3 Fundamentals DAG Authoring Study Guide

2: DAG versioning and DAG bundles (Airflow 3)

Airflow 3 introduced two pieces of infrastructure that jointly control which code a DAG run actually executes: automatic DAG versioning, which records a new version whenever the DAG's structure changes, and DAG bundles, which decide whether a rerun or backfill picks up the latest code or the historical commit that produced the run. This chapter covers when a version is recorded, how the UI exposes version history and preserves removed tasks in the grid view, how to register and choose between `LocalDagBundle` and `GitDagBundle`, how to declare bundles through `dag_bundle_config_list` and the equivalent environment variable, and how the `rerun_with_latest_version` override behaves when you deliberately want a rerun to jump to the newest code.