Three config.yml options are never read: color_log_error_keywords, color_log_warning_keywords, ignore_first_depends_on_past_by_default

[kutsibalci]

Apache Airflow version

main at 299ca2c85 (also present in 3.2.x).

What happened?

Three options in airflow-core/src/airflow/config_templates/config.yml are never read. Their names do not appear anywhere else in the repository — not in Python, not in the React UI, not in the Helm chart, not in the docs.

config.yml	option	added	references outside config.yml
:1140	[logging] color_log_error_keywords	2.10.0	0
:1148	[logging] color_log_warning_keywords	2.10.0	0
:2737	[scheduler] ignore_first_depends_on_past_by_default	2.3.0	0

None of the three carries version_deprecated or deprecation_reason, so they are presented as current settings: config.yml drives both the generated airflow.cfg and the configuration reference. Someone reading the docs sets one of these and nothing happens, with no warning.

The two color_log_*_keywords entries say the keywords "should display the line in red color in UI". Nothing reads them, and error_keywords / warning_keywords appear nowhere else either — including the 597 .tsx files under airflow-core/src/airflow/ui, so it is not a case of the UI having taken the setting over under a camelCase name.

ignore_first_depends_on_past_by_default is the one I would most like a second opinion on, because it is a scheduling setting rather than a cosmetic one and its description promises real behaviour ("first task instance of a task ignore depends_on_past setting").

I could not check when each stopped being read — my clone is shallow. If that matters I am happy to look again with full history.

What you think should happen instead?

Whichever you prefer — the project already has both patterns:

• mark them with version_deprecated / deprecation_reason, the way [traces] otel_debug_traces_on is marked ("This parameter is no longer used"), so they stay listed but honestly; or
• remove the entries.

I did not want to pick, since removing a listed option is a compatibility decision and the deprecation path is yours.

How to reproduce

$ grep -rI -w color_log_error_keywords . | grep -v config_templates/config.yml | wc -l
0
$ grep -rI -w color_log_warning_keywords . | grep -v config_templates/config.yml | wc -l
0
$ grep -rI -w ignore_first_depends_on_past_by_default . | grep -v config_templates/config.yml | wc -l
0

grep -rI covers every text file in the tree, not just Python.

Anything else?

How this was found, and what I ruled out. I parsed every option out of config.yml (323 options across 25 sections) and compared it against every place the code names a section and an option together (509 distinct pairs).

The raw comparison flagged 49 options. All but three were false positives, and the reasons are worth stating so nobody repeats them:

• Keyword form. conf.getboolean(section="secrets", key="use_cache", fallback=False) — the two strings are not adjacent.
• Factory helpers. _config_int_factory("dag_processor", "parsing_processes") and _config_bool_factory("scheduler", "catchup_by_default") never mention conf.
• Aliased import. airflow_conf.getboolean("core", "dags_are_paused_at_creation") in models/dag.py.
• Whole-section reads. conf.getsection("sentry") and conf.getsection(section, team_name=...) in BaseExecutor pull every option in [sentry] and [api] at once.
• Indirection through a dict. sql_alchemy_connect_args_async is live but reached via {"async": "sql_alchemy_connect_args_async"} in settings.py:354, so its name is never next to "database".
• My own reading error. I first looked for is_deprecated: true and found none, which made [traces] otel_debugging_on and [traces] otel_debug_traces_on look dead. config.yml marks retirement with version_deprecated / deprecation_reason, and both of those are already marked. They are not part of this report.

Only the three above survived, and each was then checked with a whole-repository search across all file types rather than trusting the comparison.

Are you willing to submit PR?

• Yes I am willing to submit a PR — happy to do either the deprecation markers or the removals, once you say which.

Gen AI usage

AI-assisted (Claude Code, Opus 5). The comparison script and this report were produced with the tool. I verified the findings myself before filing: I confirmed each of the three names has zero occurrences outside config.yml across every file type including the TypeScript UI, read settings.py to see how sql_alchemy_connect_args_async is actually reached, read the [metrics] and [traces] blocks to find the version_deprecated markers I had initially missed, and went through each false-positive class above one at a time instead of reporting the script's raw output. I understand the finding and take responsibility for it.

Code of Conduct

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