[AIRFLOW-5621] - Failure callback is not triggered when marked Failed on UI

[bharathpalaksha]

Make sure you have checked all steps below.

Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title.

Description

• When a task is marked 'Failed' on UI, on_failure_callback on the task is not triggered.

Tests

• My PR adds the following unit tests
  test_mark_failure_on_failure_callback

Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

[codecov-io]

Codecov Report

Merging #7025 into master will decrease coverage by 0.13%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7025      +/-   ##
==========================================
- Coverage   84.86%   84.72%   -0.14%     
==========================================
  Files         680      680              
  Lines       38644    38751     +107     
==========================================
+ Hits        32795    32833      +38     
- Misses       5849     5918      +69

Impacted Files	Coverage Δ
airflow/jobs/local_task_job.py	89.74% <100%> (+0.41%)	⬆️
airflow/kubernetes/volume_mount.py	44.44% <0%> (-55.56%)	⬇️
airflow/kubernetes/volume.py	52.94% <0%> (-47.06%)	⬇️
airflow/kubernetes/pod_launcher.py	45.25% <0%> (-46.72%)	⬇️
airflow/kubernetes/refresh_config.py	50.98% <0%> (-23.53%)	⬇️
...rflow/contrib/operators/kubernetes_pod_operator.py	78.75% <0%> (-20%)	⬇️
airflow/jobs/scheduler_job.py	88.84% <0%> (-0.46%)	⬇️
airflow/models/dagrun.py	96.15% <0%> (-0.44%)	⬇️
airflow/models/dag.py	90.62% <0%> (-0.34%)	⬇️
airflow/models/baseoperator.py	96.25% <0%> (ø)	⬆️
... and 6 more

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[potiuk]

I will gladly approve it. However I think this one should be mentioned in UPDATING.md ! It's a change that people might not expect.

[bharathpalaksha]

@potiuk I have made the changes to UPDATING.md