[Airflow 3.x] AIRFLOW__EMAIL__DEFAULT_EMAIL_ON_FAILURE config exists but is not read by SDK

[erinforman]

Apache Airflow version

3.1.4 (also affects 3.0.x, 3.1.x)

What happened?

The configuration option default_email_on_failure (and default_email_on_retry) is documented in the Configuration Reference and present in the config template, but the Airflow 3 SDK does not read this value.

Configuration (documented and present in config template):

# config_templates/config.yml
default_email_on_failure:
  description: |
    Whether email alerts should be sent when a task failed
  version_added: 2.0.0
  type: boolean
  default: "True"

SDK behavior (ignores config):

# airflow/sdk/bases/operator.py - Line 217
OPERATOR_DEFAULTS: dict[str, Any] = {
    "email_on_failure": True,  # Hardcoded, does not read from config
    "email_on_retry": True,
}

Airflow 2.x behavior (read from config):

# airflow/models/baseoperator.py
email_on_failure: bool = conf.getboolean("email", "default_email_on_failure", fallback=True)

What you think should happen instead?

One of the following:

1. Option A (Preferred): The SDK should read the config value like Airflow 2.x did, maintaining backward compatibility for users who set these configs.

2. Option B: If the config is intentionally no longer used, it should be marked as deprecated in the configuration reference and config template, with a note directing users to set email_on_failure explicitly in default_args instead.

Currently there's an inconsistency:

• The operator parameters (email, email_on_failure) are deprecated with warnings pointing to SmtpNotifier (PR Deprecating email, email_on_retry, email_on_failure in BaseOperator #47146)
• The config options (default_email_on_failure) are still documented without deprecation notices, but are silently ignored

How to reproduce

1. Set environment variable:

   export AIRFLOW__EMAIL__DEFAULT_EMAIL_ON_FAILURE=False

2. Create a DAG with email set but no explicit email_on_failure:

   default_args = {
       "email": ["team@example.com"],
       # email_on_failure not set - should inherit from config
   }

3. Trigger a task failure

4. Expected (Airflow 2.x behavior): No email sent (config is False)

5. Actual (Airflow 3.x behavior): Email attempted (SDK hardcodes True)

Operating System

Linux / macOS

Versions of Apache Airflow Providers

N/A - core issue

Deployment

Docker-Compose, Kubernetes (Helm)

Deployment details

No response

Anything else?

Related:

• PR Deprecating email, email_on_retry, email_on_failure in BaseOperator #47146 deprecated the operator parameters but didn't address the config options
• The mailing list discussion "[DISCUSS] Drop email integration from Airflow Core" focused on operator-level changes

Workaround: Explicitly set email_on_failure=False in default_args:

default_args = {
    "email": ["team@example.com"],
    "email_on_failure": False,  # Must be explicit in Airflow 3
}

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[chen0427ok]

Hi, I would like to work on this issue.
I have gone through the description and the related config options, and I plan to investigate why AIRFLOW__EMAIL__DEFAULT_EMAIL_ON_FAILURE is not picked up by the Task SDK and add tests to cover the expected behavior.

Could you please let me know if anyone is already working on this, or if there are any additional requirements or design preferences before I get started?

If it is available, may I take this issue?

[potiuk]

Feel free - we have no idea if others are working (but that's not a problem) - and I think expectation in here are all described here.

[erinforman]

@chen0427ok feel free to pick it up. thank you!

[justinpakzad]

Can I give this one a go if nobody is currently working on it? Cheers.

[potiuk]

Feel free - unless @chen0427ok objects