Fix failure for None task summaries

Alternative fix to #23908 - with added typing.

airflow/models/abstractoperator.py

@@ -101,6 +101,7 @@ class AbstractOperator(LoggingMixin, DAGNode):
 
     owner: str
     task_id: str
+    is_mapped: ClassVar[bool]
 
     HIDE_ATTRS_FROM_UI: ClassVar[FrozenSet[str]] = frozenset(
         (

airflow/www/utils.py

@@ -40,6 +40,7 @@
 
 from airflow import models
 from airflow.models import errors
+from airflow.models.abstractoperator import AbstractOperator
 from airflow.models.dagrun import DagRun
 from airflow.models.taskinstance import TaskInstance
 from airflow.utils import timezone
@@ -128,7 +129,7 @@ def get_mapped_summary(parent_instance, task_instances):
     }
 
 
-def get_task_summary(dag_run: DagRun, task, session: Session) -> Optional[Dict[str, Any]]:
+def get_task_summary(dag_run: DagRun, task: AbstractOperator, session: Session) -> Optional[Dict[str, Any]]:
     task_instance = (
         session.query(TaskInstance)
         .filter(

airflow/www/views.py

@@ -32,7 +32,7 @@
 from functools import wraps
 from json import JSONDecodeError
 from operator import itemgetter
-from typing import Any, Callable, Dict, List, Optional, Set, Tuple, Union
+from typing import Any, Callable, Dict, Iterable, List, Optional, Set, Tuple, Union
 from urllib.parse import parse_qsl, unquote, urlencode, urlparse
 
 import lazy_object_proxy
@@ -126,6 +126,7 @@
 from airflow.utils.session import NEW_SESSION, create_session, provide_session
 from airflow.utils.state import State, TaskInstanceState
 from airflow.utils.strings import to_boolean
+from airflow.utils.task_group import TaskGroup
 from airflow.utils.timezone import td_format, utcnow
 from airflow.version import version
 from airflow.www import auth, utils as wwwutils
@@ -250,15 +251,26 @@ def _safe_parse_datetime(v):
         abort(400, f"Invalid datetime: {v!r}")
 
 
-def task_group_to_grid(task_item_or_group, dag, dag_runs, session):
+def task_group_to_grid(
+    task_item_or_group: Union[AbstractOperator, TaskGroup],
+    dag: DAG,
+    dag_runs: Iterable[DagRun],
+    session: Session,
+) -> Dict[str, Any]:
     """
     Create a nested dict representation of this TaskGroup and its children used to construct
     the Graph.
     """
     if isinstance(task_item_or_group, AbstractOperator):
+        task_instances: List[Dict[str, Any]] = [
+            ts
+            for ts in filter(
+                None, (wwwutils.get_task_summary(dr, task_item_or_group, session) for dr in dag_runs)
+            )
+        ]
         return {
             'id': task_item_or_group.task_id,
-            'instances': [wwwutils.get_task_summary(dr, task_item_or_group, session) for dr in dag_runs],
+            'instances': task_instances,
             'label': task_item_or_group.label,
             'extra_links': task_item_or_group.extra_links,
             'is_mapped': task_item_or_group.is_mapped,
@@ -267,9 +279,11 @@ def task_group_to_grid(task_item_or_group, dag, dag_runs, session):
     # Task Group
     task_group = task_item_or_group
 
-    children = [task_group_to_grid(child, dag, dag_runs, session) for child in task_group.topological_sort()]
+    children: List[Dict[str, Any]] = [
+        task_group_to_grid(child, dag, dag_runs, session) for child in task_group.topological_sort()
+    ]
 
-    def get_summary(dag_run, children):
+    def get_summary(dag_run: DagRun, children: List[Dict[str, Any]]):
         child_instances = [child['instances'] for child in children if 'instances' in child]
         child_instances = [item for sublist in child_instances for item in sublist]