Use the libyaml FullLoader when libyaml is available - #70943
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The YAML helper modules promise that YAML operations use the faster C implementation whenever libyaml is installed. For FullLoader that promise was never kept: the branch that looked up CFullLoader discarded its result, so callers always received the pure-Python loader.
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August 3, 2026 12:57
rjgoyln
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bugraoz93,
dheerajturaga,
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August 3, 2026 12:57
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Summary
These YAML helpers promise the libyaml C implementation whenever it is available.
safe_loadanddumpdeliver it;FullLoadernever has — the__getattr__branch that looks upCFullLoaderdiscards the result and falls through to the pure-Python loader, so the fast path has always been dead code.Change
The module exists in three copies —
airflow.utils,airflow.sdk,airflowctl.ctl.utils— all carrying the same defect, and all three are fixed here. Unifying them is out of scope and already tracked by a TODO in the airflow-ctl copy.Tests
One test per copy, each failing without its fix.
CFullLoaderis injected rather than assumed, so the assertion holds whether or not the machine running the tests has libyaml compiled in.Behavior change
No in-tree caller reads
FullLoaderthrough these wrappers, so nothing in Airflow changes. External callers now receiveCFullLoader, which does not see constructors registered viayaml.add_constructor(tag, fn).Was generative AI tooling used to co-author this PR?
Generated-by: Claude Code (Opus 5) following the guidelines