changelog-armed.sh asks only whether the TOP section agrees with VERSION.
A PR that replaces '## X.Y.Z — DATE' with its own '## Unreleased' block —
git merges the edit cleanly, and a shipped section is silently absorbed into
Unreleased. The damage only surfaces at the next release, when
release-notes.sh cannot find the section it extracts by heading.
Add changelog-monotonic.sh: the set of '^## X.Y.Z' headings on a branch must
be a superset of the set at the merge base. Release headings are append-only,
so the rule has no legitimate violation — and the ceremony's stamp passes by
construction, adding X.Y.Z and removing none.
Its own script, not a clause in changelog-armed.sh: the input is a git
history rather than two files, no base ref is a SKIP rather than a failure,
and changelog-armed.sh is driven by test/release.sh against constructed
non-git trees that cannot express the failure at all.
CI checks out with fetch-depth: 0 and sets CHANGELOG_MONOTONIC_STRICT=1, so
an unreachable base ref goes red there instead of degrading to the skip a
local run is allowed.
Closes#122
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
ce57070c14