Follow-up to v2.9.19: deriving lastBuildDate from _meta.last_updated only moved
the drift one level — that analysis timestamp is itself bumped on every publish
even when the ranked content is unchanged, so feed.xml kept differing between
develop and master. Use the freshest item's content date instead (the items only
change when the ranking actually changes). Verified: deterministic across reruns,
and the develop and master digests both yield 2026-06-18, so feed.xml is now
byte-identical across branches — the drift is fully eliminated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
rss_generator set <lastBuildDate> to datetime.utcnow(), so every republish
rewrote it even when the digest was unchanged — leaving a 1-line develop<->master
drift in v2-docs/feed.xml (the residual after the PR Guardian drift fix). Derive
it from the digest's _meta.last_updated (the actual analysis date), falling back
to the most recent item date, so the feed is a pure function of its input:
regenerating unchanged content now yields byte-identical output. Verified
deterministic across repeated runs.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
