FORMAT_MAJOR becomes 1 and FORMAT_MINOR restarts at 0. The decoder
stops being exact-major-only: it classifies three ways through a named
FormatEpoch carried on FixedHeader, so major 0 is decoded deliberately
as legacy rather than refused. Old readers already fail closed on an
unknown major, so that half needed no mechanism — which is why the major
is the right carrier, and why the header's immutability, fatal to
FORMAT_MINOR as a provenance field, is what makes it sound as an epoch
field.
The matrix: a major-0 bundle with no base may open; one carrying a base
is refused; one attempting to add a base is refused and told to repack.
That last row is the non-inheritance rule. Three errors, none of which
degrades to read-only: two permanent legacy/repack errors, and
ReductionAuthorityUnavailable, which is temporary, names P13-S27, and
must not say repack — a major-1 container is already the right epoch.
Until P13-S27 lands, both major-1 base boundaries are closed: opening a
major-1 bundle that already carries a base, and committing one into it.
Neither may be left open while the epoch asserts a validation that never
ran.
Text projection cannot mint a base. serialize_document staged a carried
base into a fresh bundle and build_manifest wrote it, so an old or
hand-authored document could be laundered straight through the boundary.
All three sides now refuse: projection, parsing, and a new dedicated
SerializeError variant — none of which existed to be "retained".
COMPANION_VERSION moves to 0.14.0 and the corpus is rebuilt to 20
vectors and ten rejection classes, with canonical_bases reach dropping
2 -> 0. That is a real capability loss and is recorded as one.
Corruption keeps precedence in both epochs: a corrupt major-1 base fails
as malformed, never as the temporary authority error a user would
reasonably retry.
All 11 mutations were run and observed, not reasoned about. M4 is the
signing one — with the legacy commit refusal removed, a legacy container
gains a base in place, which is exactly the counterexample that killed
FORMAT_MINOR. M11 confirms the third error is distinct while test 3
stays green, proving the mutation stayed inside the major-1 branches. M7
fails on both epoch halves. M8 falls through to
SerializeError::Bundle(ReductionAuthorityUnavailable), confirming the
text layer's own refusal is what the test asserts.
Two touch-table gaps surfaced during execution, both the same shape: a
.tex requirement addition moves hardcoded counts in
requirement_labels.rs, and the companion bump moves a second normative
version literal spelled version~0.13.0 rather than (0 13 0). Neither
file was in any touch table; the second was caught only because a test
exists for exactly that failure.
P13-S27 is unblocked — its pin 2a is resolved from outside, as its own
prohibition required — and inherits three obligations: both interim
refusals converted to validation, M8's deferred laundering
demonstration, and pin 3c's two suspended conformance assertions.
P13-S16 remains blocked on S27.
Workspace green at 1569.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Levi Neuwirth
bc06706e41