Python 3.14 Support

.github/actions/migration_tests/action.yml

@@ -31,9 +31,13 @@ runs:
         MIN_AIRFLOW_VERSION="$(
           python ./scripts/ci/testing/get_min_airflow_version_for_python.py "${PYTHON_VERSION}"
         )"
+        AIRFLOW_EXTRAS=""
+        if [[ "${MIN_AIRFLOW_VERSION}" =~ ^2\. ]]; then
+          AIRFLOW_EXTRAS="--airflow-extras pydantic"
+        fi
         breeze shell "${AIRFLOW_2_CMD}" \
           --use-airflow-version "${MIN_AIRFLOW_VERSION}" \
-          --airflow-extras pydantic \
+          ${AIRFLOW_EXTRAS} \
           --answer y &&
         breeze shell "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${DB_MANGERS}
                     ${AIRFLOW_3_CMD}" --no-db-cleanup
@@ -61,9 +65,13 @@ runs:
         MIN_AIRFLOW_VERSION="$(
           python ./scripts/ci/testing/get_min_airflow_version_for_python.py "${PYTHON_VERSION}"
         )"
+        AIRFLOW_EXTRAS=""
+        if [[ "${MIN_AIRFLOW_VERSION}" =~ ^2\. ]]; then
+          AIRFLOW_EXTRAS="--airflow-extras pydantic"
+        fi
         breeze shell "${AIRFLOW_2_CMD}" \
           --use-airflow-version "${MIN_AIRFLOW_VERSION}" \
-          --airflow-extras pydantic \
+          ${AIRFLOW_EXTRAS} \
           --answer y &&
         breeze shell "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${DB_MANGERS}
              ${AIRFLOW_3_CMD}" --no-db-cleanup

.github/workflows/run-unit-tests.yml

@@ -203,7 +203,9 @@ jobs:
         uses: ./.github/actions/migration_tests
         with:
           python-version: ${{ matrix.python-version }}
-        if: inputs.run-migration-tests == 'true' && inputs.test-group == 'core'
+        # Any new python version should be disabled below via `&& matrix.python-version != '3.xx'` until the first
+        # Airflow version that supports it is released - otherwise there's nothing to migrate back to.
+        if: inputs.run-migration-tests == 'true' && inputs.test-group == 'core' && matrix.python-version != '3.14'
       - name: >
           ${{ inputs.test-group }}:${{ inputs.test-scope }} Tests ${{ inputs.test-name }} ${{ matrix.backend-version }}
           Py${{ matrix.python-version }}:${{ env.PARALLEL_TEST_TYPES }}

.pre-commit-config.yaml

@@ -585,6 +585,7 @@ repos:
         exclude: >
           (?x)
           ^README\.md$|
+          ^pyproject\.toml$|
           ^generated/PYPI_README\.md$|
           ^airflow-core/docs/.*commits\.rst$|
           ^airflow-core/newsfragments/41368\.significant\.rst$|
@@ -816,6 +817,17 @@ repos:
           ^providers/.*/provider\.yaml$
         pass_filenames: false
         require_serial: true
+      - id: check-excluded-provider-markers
+        name: Check excluded-provider python_version markers in pyproject.toml
+        language: python
+        entry: ./scripts/ci/prek/check_excluded_provider_markers.py
+        files: >
+          (?x)
+          ^pyproject\.toml$|
+          ^providers/.*/provider\.yaml$
+        pass_filenames: false
+        require_serial: true
+        additional_dependencies: ['packaging>=25', 'pyyaml', 'tomli>=2.0.1', 'rich>=13.6.0']
       - id: update-reproducible-source-date-epoch
         name: Update Source Date Epoch for reproducible builds
         language: python

Dockerfile

@@ -810,7 +810,15 @@ function common::get_constraints_location() {
         echo
         echo "${COLOR_BLUE}Downloading constraints from ${AIRFLOW_CONSTRAINTS_LOCATION} to ${HOME}/constraints.txt ${COLOR_RESET}"
         echo
-        curl -sSf -o "${HOME}/constraints.txt" "${AIRFLOW_CONSTRAINTS_LOCATION}"
+        if ! curl -sSf -o "${HOME}/constraints.txt" "${AIRFLOW_CONSTRAINTS_LOCATION}"; then
+            echo
+            echo "${COLOR_YELLOW}Constraints file not found at ${AIRFLOW_CONSTRAINTS_LOCATION} (new Python version being bootstrapped?).${COLOR_RESET}"
+            echo "${COLOR_YELLOW}Falling back to no-constraints installation.${COLOR_RESET}"
+            echo
+            AIRFLOW_CONSTRAINTS_LOCATION=""
+            # Create an empty constraints file so --constraint flag still works
+            touch "${HOME}/constraints.txt"
+        fi
     else
         echo
         echo "${COLOR_BLUE}Copying constraints from ${AIRFLOW_CONSTRAINTS_LOCATION} to ${HOME}/constraints.txt ${COLOR_RESET}"

Dockerfile.ci

@@ -750,7 +750,15 @@ function common::get_constraints_location() {
         echo
         echo "${COLOR_BLUE}Downloading constraints from ${AIRFLOW_CONSTRAINTS_LOCATION} to ${HOME}/constraints.txt ${COLOR_RESET}"
         echo
-        curl -sSf -o "${HOME}/constraints.txt" "${AIRFLOW_CONSTRAINTS_LOCATION}"
+        if ! curl -sSf -o "${HOME}/constraints.txt" "${AIRFLOW_CONSTRAINTS_LOCATION}"; then
+            echo
+            echo "${COLOR_YELLOW}Constraints file not found at ${AIRFLOW_CONSTRAINTS_LOCATION} (new Python version being bootstrapped?).${COLOR_RESET}"
+            echo "${COLOR_YELLOW}Falling back to no-constraints installation.${COLOR_RESET}"
+            echo
+            AIRFLOW_CONSTRAINTS_LOCATION=""
+            # Create an empty constraints file so --constraint flag still works
+            touch "${HOME}/constraints.txt"
+        fi
     else
         echo
         echo "${COLOR_BLUE}Copying constraints from ${AIRFLOW_CONSTRAINTS_LOCATION} to ${HOME}/constraints.txt ${COLOR_RESET}"
@@ -1729,6 +1737,7 @@ ENV AIRFLOW_REPO=${AIRFLOW_REPO}\
     AIRFLOW_VERSION_SPECIFICATION="" \
     PIP_PROGRESS_BAR=${PIP_PROGRESS_BAR} \
     ADDITIONAL_PIP_INSTALL_FLAGS=${ADDITIONAL_PIP_INSTALL_FLAGS} \
+    INCLUDE_PRE_RELEASE="true" \
     CASS_DRIVER_BUILD_CONCURRENCY=${CASS_DRIVER_BUILD_CONCURRENCY} \
     CASS_DRIVER_NO_CYTHON=${CASS_DRIVER_NO_CYTHON}
 

airflow-core/docs/installation/prerequisites.rst

@@ -20,7 +20,7 @@ Prerequisites
 
 Airflow® is tested with:
 
-* Python: 3.10, 3.11, 3.12, 3.13
+* Python: 3.10, 3.11, 3.12, 3.13, 3.14
 
 * Databases:
 

airflow-core/pyproject.toml

@@ -36,12 +36,11 @@ description = "Core packages for Apache Airflow, schedule and API server"
 readme = { file = "README.md", content-type = "text/markdown" }
 license = "Apache-2.0"
 license-files = ["LICENSE", "NOTICE"]
-# We know that it will take a while before we can support Python 3.14 because of all our dependencies
-# It takes about 4-7 months after Python release before we can support it, so we limit it to <3.14
-# proactively. This way we also have a chance to test it with Python 3.14 and bump the upper binding
-# and manually mark providers that do not support it yet with !-3.14 - until they support it - which will
-# also exclude resolving uv workspace dependencies for those providers.
-requires-python = ">=3.10,!=3.14"
+# Supporting new Python releases typically takes 4-7 months due to all our dependencies.
+# We proactively exclude the next major version to avoid dependency conflicts, then test it and
+# bump the upper binding once ready. Providers that don't support it yet are marked with
+# != constraint - until they support it - which also excludes resolving uv workspace dependencies.
+requires-python = ">=3.10,!=3.15"
 authors = [
     { name = "Apache Software Foundation", email = "dev@airflow.apache.org" },
 ]
@@ -60,6 +59,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
     "Topic :: System :: Monitoring",
 ]
 
@@ -80,7 +80,8 @@ dependencies = [
     # The 1.13.0 of alembic marked some migration code as SQLAlchemy 2+ only so we limit it to 1.13.1
     "alembic>=1.13.1, <2.0",
     "argcomplete>=1.10",
-    "asgiref>=2.3.0",
+    "asgiref>=2.3.0; python_version < '3.14'",
+    "asgiref>=3.11.1; python_version >= '3.14'",
     "attrs>=22.1.0, !=25.2.0",
     "cadwyn>=6.0.4",
     "colorlog>=6.8.2",
@@ -103,7 +104,8 @@ dependencies = [
     "jinja2>=3.1.5",
     "jsonschema>=4.19.1",
     "lazy-object-proxy>=1.2.0",
-    'libcst >=1.8.2',
+    'libcst >=1.8.2; python_version < "3.14"',
+    'libcst >=1.8.6; python_version >= "3.14"',
     "linkify-it-py>=2.0.0",
     "lockfile>=0.12.2",
     "methodtools>=0.4.7",
@@ -138,8 +140,7 @@ dependencies = [
     "rich-argparse>=1.0.0",
     "rich>=13.6.0",
     "setproctitle>=1.3.3",
-    # SQLAlchemy >=2.0.36 fixes Python 3.13 TypingOnly import AssertionError caused by new typing attributes (__static_attributes__, __firstlineno__)
-    "sqlalchemy[asyncio]>=2.0.36",
+    "sqlalchemy[asyncio]>=2.0.48",
     "svcs>=25.1.0",
     "tabulate>=0.9.0",
     "tenacity>=8.3.0",
@@ -173,7 +174,8 @@ dependencies = [
 "async" = [
     "eventlet>=0.37.0",
     "gevent>=25.4.1",
-    "greenlet>=3.1.0",
+    "greenlet>=3.1.0; python_version < '3.14'",
+    "greenlet>=3.3.2; python_version >= '3.14'",
     "greenback>=1.2.1",
 ]
 "graphviz" = [

airflow-core/src/airflow/typing_compat.py

@@ -29,4 +29,5 @@
 if sys.version_info >= (3, 11):
     from typing import Self, Unpack, assert_never
 else:
+    # TODO: Remove once Python 3.10 support is dropped (EOL 2026)
     from typing_extensions import Self, Unpack, assert_never

airflow-core/tests/unit/always/test_example_dags.py

@@ -66,6 +66,9 @@
 IGNORE_EXAMPLE_DAGS: tuple[str, ...] = (
     # These example dags require suspended providers, eg: google dataflow dependent on the Apache Beam provider,
     # but it's in the suspended list, we can't import the dag
+    # Ray uses pydantic v1 internally, which fails to infer types in Python 3.14.
+    # TODO: remove once ray releases a version with Python 3.14 support.
+    "providers/google/tests/system/google/cloud/ray/example_ray_job.py",
     "providers/google/tests/system/google/cloud/dataflow/example_dataflow_go.py",
     "providers/google/tests/system/google/cloud/dataflow/example_dataflow_java_streaming.py",
     "providers/google/tests/system/google/cloud/dataflow/example_dataflow_native_java.py",

airflow-core/tests/unit/api_fastapi/auth/managers/simple/conftest.py

@@ -18,6 +18,7 @@
 
 from __future__ import annotations
 
+import contextlib
 import os
 
 import pytest
@@ -33,7 +34,7 @@
 @pytest.fixture
 def auth_manager():
     auth_manager = SimpleAuthManager()
-    if os.path.exists(auth_manager.get_generated_password_file()):
+    with contextlib.suppress(FileNotFoundError):
         os.remove(auth_manager.get_generated_password_file())
     return auth_manager
 

airflow-core/tests/unit/api_fastapi/common/test_http_access_log.py

@@ -123,7 +123,7 @@ async def lifespan_app(scope, receive, send):
     import asyncio
 
     with structlog.testing.capture_logs() as logs:
-        asyncio.get_event_loop().run_until_complete(middleware({"type": "lifespan"}, None, None))
+        asyncio.run(middleware({"type": "lifespan"}, None, None))
 
     assert logs == []
 

airflow-core/tests/unit/executors/test_local_executor.py

@@ -41,10 +41,16 @@
 
 pytestmark = pytest.mark.db_test
 
-# Runtime is fine, we just can't run the tests on macOS
-skip_spawn_mp_start = pytest.mark.skipif(
-    multiprocessing.get_context().get_start_method() == "spawn",
-    reason="mock patching in test don't work with 'spawn' mode (default on macOS)",
+# Mock patching doesn't work across process boundaries with 'spawn' (default on macOS)
+# or 'forkserver' (default on Linux with Python 3.14+).
+skip_non_fork_mp_start = pytest.mark.skipif(
+    multiprocessing.get_start_method() != "fork",
+    reason="mock patching in test doesn't work with non-fork multiprocessing start methods",
+)
+
+skip_fork_mp_start = pytest.mark.skipif(
+    multiprocessing.get_start_method() == "fork",
+    reason="tests non-fork (lazy-spawning) behavior",
 )
 
 
@@ -68,7 +74,7 @@ def test_supports_multi_team(self):
     def test_serve_logs_default_value(self):
         assert LocalExecutor.serve_logs
 
-    @skip_spawn_mp_start
+    @skip_non_fork_mp_start
     @mock.patch.object(gc, "unfreeze")
     @mock.patch.object(gc, "freeze")
     def test_executor_worker_spawned(self, mock_freeze, mock_unfreeze):
@@ -82,6 +88,33 @@ def test_executor_worker_spawned(self, mock_freeze, mock_unfreeze):
 
         executor.end()
 
+    @skip_fork_mp_start
+    @mock.patch.object(gc, "unfreeze")
+    @mock.patch.object(gc, "freeze")
+    def test_executor_lazy_worker_spawning(self, mock_freeze, mock_unfreeze):
+        """On non-fork start methods, workers are spawned lazily and gc.freeze is not called."""
+        executor = LocalExecutor(parallelism=3)
+        executor.start()
+
+        try:
+            # No workers should be pre-spawned
+            assert len(executor.workers) == 0
+            mock_freeze.assert_not_called()
+            mock_unfreeze.assert_not_called()
+
+            # Simulate a queued message so _check_workers spawns one worker on demand
+            with executor._unread_messages:
+                executor._unread_messages.value = 1
+            executor.activity_queue.put(None)  # poison pill so the worker exits cleanly
+            executor._check_workers()
+
+            assert len(executor.workers) == 1
+            # gc.freeze is still not used for non-fork
+            mock_freeze.assert_not_called()
+        finally:
+            executor.end()
+
+    @skip_non_fork_mp_start
     @mock.patch("airflow.sdk.execution_time.supervisor.supervise")
     def test_execution(self, mock_supervise):
         success_tis = [
@@ -182,7 +215,7 @@ def test_gauge_executor_metrics(self, mock_stats_gauge, mock_trigger_tasks, mock
         mock_stats_gauge.assert_has_calls(calls)
 
     @skip_if_force_lowest_dependencies_marker
-    @pytest.mark.execution_timeout(5)
+    @pytest.mark.execution_timeout(30)
     def test_clean_stop_on_signal(self):
         import signal
 
@@ -303,8 +336,15 @@ def test_multiple_team_executors_isolation(self):
 
             # Verify each executor has its own workers dict
             assert team_a_executor.workers is not team_b_executor.workers
-            assert len(team_a_executor.workers) == 2
-            assert len(team_b_executor.workers) == 3
+
+            if LocalExecutor.is_mp_using_fork:
+                # fork pre-spawns all workers at start()
+                assert len(team_a_executor.workers) == 2
+                assert len(team_b_executor.workers) == 3
+            else:
+                # forkserver/spawn use lazy spawning
+                assert len(team_a_executor.workers) == 0
+                assert len(team_b_executor.workers) == 0
 
             # Verify each executor has its own unread_messages counter
             assert team_a_executor._unread_messages is not team_b_executor._unread_messages
@@ -327,8 +367,11 @@ def test_global_executor_without_team_name(self):
 
         executor.start()
 
-        # Verify workers were created
-        assert len(executor.workers) == 2
+        if LocalExecutor.is_mp_using_fork:
+            assert len(executor.workers) == 2
+        else:
+            # forkserver/spawn use lazy spawning
+            assert len(executor.workers) == 0
 
         executor.end()
 
@@ -338,7 +381,7 @@ def test_supports_callbacks_flag_is_true(self):
         executor = LocalExecutor()
         assert executor.supports_callbacks is True
 
-    @skip_spawn_mp_start
+    @skip_non_fork_mp_start
     @mock.patch("airflow.executors.workloads.callback.execute_callback_workload")
     def test_process_callback_workload(self, mock_execute_callback):
         mock_execute_callback.return_value = (True, None)