Issue deprecation warning for plugins registering ti_deps

This is removed in Airflow3 via #45713

airflow/plugins_manager.py

@@ -27,6 +27,7 @@
 import os
 import sys
 import types
+import warnings
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Iterable
 
@@ -431,6 +432,17 @@ def initialize_ti_deps_plugins():
     registered_ti_dep_classes = {}
 
     for plugin in plugins:
+        if not plugin.ti_deps:
+            continue
+
+        from airflow.exceptions import RemovedInAirflow3Warning
+
+        warnings.warn(
+            "Using custom `ti_deps` on operators has been removed in Airflow 3.0",
+            RemovedInAirflow3Warning,
+            stacklevel=1,
+        )
+
         registered_ti_dep_classes.update(
             {qualname(ti_dep.__class__): ti_dep.__class__ for ti_dep in plugin.ti_deps}
         )

tests/plugins/test_plugins_manager.py

@@ -28,6 +28,7 @@
 
 import pytest
 
+from airflow.exceptions import RemovedInAirflow3Warning
 from airflow.hooks.base import BaseHook
 from airflow.listeners.listener import get_listener_manager
 from airflow.plugins_manager import AirflowPlugin
@@ -270,6 +271,17 @@ class AirflowAdminMenuLinksPlugin(AirflowPlugin):
             ),
         ]
 
+    def test_deprecate_ti_deps(self):
+        class DeprecatedTIDeps(AirflowPlugin):
+            name = "ti_deps"
+
+            ti_deps = [mock.MagicMock()]
+
+        with mock_plugin_manager(plugins=[DeprecatedTIDeps()]), pytest.warns(RemovedInAirflow3Warning):
+            from airflow import plugins_manager
+
+            plugins_manager.initialize_ti_deps_plugins()
+
     def test_should_not_warning_about_fab_plugins(self, caplog):
         class AirflowAdminViewsPlugin(AirflowPlugin):
             name = "test_admin_views_plugin"

tests/serialization/test_dag_serialization.py

@@ -539,6 +539,7 @@ def sorted_serialized_dag(dag_dict: dict):
         return actual, expected
 
     @pytest.mark.db_test
+    @pytest.mark.filterwarnings("ignore::airflow.exceptions.RemovedInAirflow3Warning")
     def test_deserialization_across_process(self):
         """A serialized DAG can be deserialized in another process."""
 
@@ -1596,6 +1597,7 @@ def test_deps_sorted(self):
             "airflow.ti_deps.deps.trigger_rule_dep.TriggerRuleDep",
         ]
 
+    @pytest.mark.filterwarnings("ignore::airflow.exceptions.RemovedInAirflow3Warning")
     def test_error_on_unregistered_ti_dep_serialization(self):
         # trigger rule not registered through the plugin system will not be serialized
         class DummyTriggerRule(BaseTIDep):
@@ -1634,6 +1636,7 @@ def test_error_on_unregistered_ti_dep_deserialization(self):
             SerializedBaseOperator.deserialize_operator(serialize_op)
 
     @pytest.mark.db_test
+    @pytest.mark.filterwarnings("ignore::airflow.exceptions.RemovedInAirflow3Warning")
     def test_serialize_and_deserialize_custom_ti_deps(self):
         from test_plugin import CustomTestTriggerRule