fix: no-op operations skip their lock; reset-window restores anchor on the committed baseline (#735, #736) by pbean · Pull Request #737 · bmad-code-org/bmad-loop

pbean · 2026-08-26T18:07:58Z

Closes #735
Closes #736

Both issues are review residuals PR #726 filed rather than patched, because each
remedy changes a decision that PR had reviewed and pinned. They land together
because they are one family — every defect in this program sits at a lock's edge.
Each was swept as a class rather than patched per report.

#736 — a lock taken for work that will not write

sprintstatus.advance acquired the board lock before _advance_locked discovered
there was nothing to write, so an idempotent replay — bmad-loop confirm against
a story the board already records as done, a designed path — could fail on lock
contention, or on a StateRootError from deriving the sidecar path, for work it
was never going to do. That is the third instance of one shape; #726 fixed the
other two (archive_closed over a missing ledger, empty batches). The issue asks
for the class, so the class is what this sweeps.

Every read-dependent no-op now takes one advisory pre-lock read and answers
from it:

sprintstatus.advance — absent row, or a row already at or past target.
deferredwork: _mark_done_many, mark_open_many, record_decision,
append_entries_published, archive_closed — ids all already done, a decision
on an entry that is not there, specs that all dedupe, nothing eligible to
archive.
Missing-ledger is_file guards above the lock in _mark_done_many,
mark_open_many and record_decision, matching what archive_closed already
did. append_entries_published deliberately gets none: an absent ledger there
means CREATE, which is a write.

The probe is advisory in the strict sense. Only a "would write nothing" answer
is acted on, and such a call linearizes at the probe's read — it publishes no
bytes, so there is nothing for a rival to interleave with. Every other answer,
and any exception raised while probing, falls through to the hold, which re-reads
and decides authoritatively; a malformed board still raises SprintStatusError
from under the lock. Each probe runs the same pure decision helper the locked
pass runs, so it cannot answer "no write" where the authority would write. Making
that possible is what the first deferredwork commit does: it extracts
_apply_done_many / _apply_open_many / _apply_appends /
_eligible_for_archive from the locked bodies with zero behavior change, and
rewires those bodies through them, so probe and authority are literally one body.

The invariant the module docstrings state is therefore relaxed, deliberately and
narrowly: from "the lock is held across every read" to "the lock is held across
every read that decides the published bytes." #736's body quotes the old
assertion as the thing a fix has to change, and it did:
test_advance_holds_the_lock_across_every_read_and_the_write is renamed, not
deleted, to test_the_reads_that_decide_the_published_bytes_are_inside_the_lock
(the old name is in its docstring for greps). Its assertion goes from
events[1:-1] == ["load", "load", "write"] to events[:enter] == ["load"] — one
advisory read, pinned to exactly one — plus the unchanged
events[enter+1:-1] == ["load", "load", "write"] for the deciding reads and the
write.

#735 — a post-reset observation used as a write anchor

Engine._restore_ledger anchored its reset_owned compare-and-set on the ledger
as observed the instant _rollback_or_pause returned. That read is taken after
the very git reset --hard it is meant to attest to, so a rival writing a tracked
ledger inside that window becomes the observation: current == observed then
holds, the branch labels the rival's text reset-owned, and the restore overwrites
it. Reading sooner narrows the window and cannot close it.

Exploration found the same shape at three write arms, not the one filed, and
all three are fixed: _restore_ledger, _restore_defer_ledger and
SweepEngine._ensure_migration.

The governing rule the fix encodes: a post-reset observation may justify a
SKIP, never a WRITE. Skips stay observation-based — declining to act is safe
whoever wrote those bytes. Every write arm is now anchored on something the rival
cannot have authored: the ledger's committed blob at task.baseline_commit, read
out of git through the existing verify.worktree_file_bytes_at_revision. That is
exactly what reset --hard republished. The probe runs outside the lock,
because it spawns git and ledger_lock may never span a subprocess (#286).

Supporting pieces:

New _ledger_rel() — the repo-relative derivation extracted out of
_ledger_is_gits_to_restore, which is rebased on it with byte-identical
observable behavior (its five existing tests pass untouched).
New _ledger_baseline_text(task) — (True, text) / (True, None) determinate
absence / (False, None) no anchor. Newlines are normalized \r\n,\r → \n
to match read_text's universal-newline mode; without that the anchor would be
silently never-true on Windows and every such restore would degrade to a skip.
Its fault direction is inverted from the gits probe, deliberately: that one
degrades to True because its consumer is an unlink and uncertainty must never
delete; this one degrades to no anchor because its only consumer is a write
arm and uncertainty must never write. Nothing escapes the helper — GitError
is a plain Exception and the attempt's net is (OSError, StateRootError), so
a leak would replace an in-flight RunPaused in that finally.
One new journal kind, ledger-baseline-probe-failed ({story_key, error}). It
needs no registration: there is no journal-kind registry or enum, machine.py
and documents.py never read kind, so this is not a --json contract change
and needs no schema bump.
SweepEngine._ensure_migration splits its top-of-attempt read so absence
survives (rewrite: str | None beside new_text: str) and deletes the
now-dead observed read, which had no skip arm to serve.

Each site degrades in the direction its own semantics allow, and none of them
writes without an anchor: _restore_ledger skips
(ledger-restore-skipped-diverged — a retraction cannot be expressed as an
append), _restore_defer_ledger merges by appending the entries disk has lost
(defer-ledger-restore-diverged — appending cannot destroy anybody's write), and
the sweep escalates for a human (sweep-migration-restore-diverged — it has no
merge to fall back to). An untracked or absent-at-baseline sweep ledger has no
blob, so its anchor is the rejected rewrite the attempt itself graded, down to
None == None when the session deleted the ledger outright.

Released-behavior deltas

An at-or-past/absent-row advance and the deferredwork no-ops no longer contend
on their lock at all, and now SUCCEED where lock-OSError/StateRootError
previously failed them — that is the fix; the write arms still fail loudly.
bmad-loop sweep --archive with nothing eligible under a dead lock / no state
root: rc 1 ("may hold its ledger lock") → rc 0 ("no closed entries to archive").
An ELIGIBLE archive under a dead lock still fails exactly as before.
_restore_ledger: the reset_owned CAS anchor trusts a post-reset observation and can overwrite a concurrent writer #735: the doubly-degraded path (gits probe fault + blob probe fault) previously
could still write via reset_owned; now it skips/merges/escalates — two failed
probes are maximal uncertainty. A probe fault in the sweep now pauses the sweep
with the "changed underneath" escalation.
ABA residuals stay residual (documented, not fixed): a rival writing text
byte-equal to the committed blob (or, sweep-untracked, to the rejected rewrite),
or landing before the sweep's top-of-attempt read, is indistinguishable in
principle.

Also in this class: a defer restore whose baseline blob cannot be read now merges
where it previously overwrote on the observation. No knowledge is lost either
way, but the published bytes differ when a rival is present. And a sweep migration
restore over an EXTERNAL ledger — no repo-relative name, so no anchor — now
escalates rather than writing.

Declined, with rationale

archive_closed's ELIGIBLE dry_run stays under the hold. Running the
preview inside the lock is a deliberate one-code-path design, not an oversight:
there is one body rather than a locked and an unlocked one. Only the
nothing-eligible case joins the probe class, because it is not a code path at
all — the probe answers it with [] before either branch is reached. Verified
byte-identical to origin/main from if dry_run: to the end of the function.
The CAS restores' under-lock skips stay. Their acquisition is load-bearing
for the write-arm decision that follows it, so it is not a lock taken for
nothing. The defect at those sites was the anchor, which is _restore_ledger: the reset_owned CAS anchor trusts a post-reset observation and can overwrite a concurrent writer #735's half of this
PR — no probe was added there that skips the lock.

Tests

+1038 / −32 across four files; 22 net-new test functions (23 definitions, one of
them the rename above) collecting 47 cases.

tests/test_sprintstatus_advance.py (+213/−12) — the renamed ordering test,
plus no-lock rows for at-or-past and absent, a no-op that succeeds when no state
root is derivable, a malformed-board fall-through, and a racing test proving the
authoritative never-regress decision is still made under the lock.
tests/test_deferredwork.py (+268/−13) — a NOOP_MUTATORS table over all ten
public entry points driving test_a_read_dependent_noop_takes_no_lock and
test_a_noop_mutation_succeeds_when_no_state_root_is_derivable, plus
test_mutators_take_no_lock_for_a_missing_ledger and
test_a_failing_probe_read_falls_through_to_the_locked_path (5 rows).
tests/test_engine.py (+426/−5) — the _restore_ledger: the reset_owned CAS anchor trusts a post-reset observation and can overwrite a concurrent writer #735 defect proof (a rival writing inside
the reset window survives), the _ledger_baseline_text unit rows including the
CRLF normalization guard and the two degrade directions, the defer-restore
merge, and a positive control that the write arm still fires on the blob anchor.
tests/test_sweep.py (+131/−2) — migration restore escalates on a tracked
rival, on an untracked rival, and on a baseline probe fault.

Two pre-existing deferredwork tests were rewritten because the probe made their
documented ablations go green: test_mark_open_many_writes_nothing_when_no_id_is_eligible
and test_record_decision_returns_false_for_a_missing_entry now assert
acquisitions == [] and point at test_a_failing_probe_read_falls_through_to_the_locked_path,
which faults only the probe read and so is the remaining grader of all five
under-lock no-write guards. Three ablation records were requalified for the same
reason — one that said "hoist the read above the lock" (now the production shape,
so it needed "AND WRITE FROM IT") and two that named the deleted expression
current == observed.

Note on grading, since it is easy to get wrong here: on a probe-fault row the
acquisition count is the oracle, never the raise — the probe's own uncaught
error is the same class from the same reader, so pytest.raises alone stays green
with the try/except deleted. And a restore-WRITE assertion over a tracked
ledger is vacuous, because reset --hard puts the file back regardless; those
rows grade the rival's survival, the journal kind, or the escalation reason.

The final audit caught one pre-existing test this PR had quietly made vacuous, and
fixed it. test_defer_skips_restore_for_a_ledger_the_reset_never_touched carried
the ablation "delete the _ledger_is_gits_to_restore gate and the rival entry is
clobbered by the snapshot" — true before this branch, green on it. The write arm
is now anchored and current == expected, and an untracked ledger has no blob at
the baseline, so expected is None and the arm cannot fire whether the gate runs
or not; control falls to the append-only merge, which writes nothing. The gate's
remaining job on that path is to short-circuit above the git spawn and the lock, so
that is what the test now asserts (probed == []), with the record rewritten to
say why the data oracles stopped discriminating. Re-ablated: it reds on the new
assertion. One further record was requalified — a sentence saying that hoisting
read#1 above the lock does not redden a racing row, which is still true but now
describes production, since the #736 probe is that hoisted read.

Audits

Lock spans reach no subprocess. An AST call-graph over src/bmad_loop,
module-qualified and resolved through the class MRO: 11 lock spans, 0 reaching
a subprocess spawn — the same count and the same zero as fix: serialize deferred-work ledger and sprint board writers cross-process (#286, #469) #726's audit. The
zero was not believed until the checker fired on a sensitivity control:
Engine._ledger_is_gits_to_restore → verify.path_tracked → verify._run_git → subprocess.run, a chain that really exists and sits outside every lock. Five
spans have a path that exists only through an unknown-receiver edge; every one
of those was adjudicated to re.Match.start() (from a finditer loop) colliding
by name with probe._ProbeLauncher.start.
advance takes the board lock before discovering a no-op, so an idempotent confirm replay can fail on contention #736 inventory. All five probes verified in place — below every validation,
above the lock, try enclosing only the probe, except Exception, returning the
same value the locked body returns, and running the same extracted helper. Three
is_file guards present with their under-hold rechecks intact;
append_entries_published has none and documents why. No probe or guard acquires
anything.
Ablations. Every negative assertion in this PR was ablation-proven during the
phase that wrote it — the guard, probe or anchor deleted, the row confirmed to
red on its intended assertion, then restored. 38 ablations across the four
implementation commits, run singly, none green. The final pass re-audited all 186
ablation records in the four touched test files against the code as it now
stands, looking for records staled either by an expression being renamed or by a
read moving above a lock: one was stale, is described above, and is fixed and
re-ablated. cp backups throughout, never git checkout — restoring an ablation
with git checkout deletes the fix it was grading.

Summary by CodeRabbit

Bug Fixes
- Read-only or already-completed operations now avoid unnecessary lock acquisition.
- Concurrent ledger updates are preserved during rollback and migration restoration.
- Restoration safely stops when the original ledger state cannot be verified, preventing unintended overwrites.
- External, untracked, and symlinked ledgers can be restored safely when supported.
- Baseline handling is more reliable, including tracked files, missing baselines, and newline normalization.
- Probe failures fall back to authoritative validation and locked execution.
Documentation
- Updated feature documentation to describe lock-free no-op checks and safer ledger restoration behavior.

#736)

…ed mutators (#736) Each locked read->edit->write folded its ids (or specs, or eligible entries) inline, so the decision only existed inside the hold. Extract each fold to a module-level pure helper — `_apply_done_many`, `_apply_open_many`, `_apply_appends`, `_eligible_for_archive` — and rewire the locked bodies through them, the argument `_apply_append`'s extraction already makes for the batched appender. Zero behavior change: the helpers are the same statements, the reads and the `atomic_write_text` call sites do not move. This is the shared body an advisory pre-lock probe needs so probe and authority cannot drift; the probes themselves land next. `_apply_done_many` carries `undo_owner` deliberately — the reopenable arm's LINE_BREAK refusal is part of the decision, so a hand-rolled scan for open entries would answer differently.

…ger lock (#736) Third instance of the class #726 closed twice here already: a lock taken for an operation that will not write turns a previously successful no-op into a failure. The acquisition can raise `OSError`, and deriving the sidecar path raises `runs.StateRootError` wherever no state root is nameable — so a replayed rollback, a re-run defer and `sweep --archive` over a ledger holding nothing closed could all fail at a lock they had no write to serialize. Two guards and five advisory probes, all above the lock and below every validation: - Missing-ledger `is_file` guards on `_mark_done_many`, `mark_open_many` and `record_decision`, the pattern `archive_closed` already kept. The rechecks under the hold stay — creation can race the answer. `append_entries_published` deliberately gets none: an absent ledger there means CREATE, which is a write. - One advisory pre-lock read per mutator, running the same pure decision helper the locked pass runs. Only a "would write nothing" answer is acted on, and such a call linearizes at the probe read — it publishes no bytes. Every other answer, and any fault during the probe, falls through to the hold, which re-reads and decides authoritatively. `archive_closed`'s probe sits above the `dry_run` branch, so a nothing-eligible dry run skips the lock too; an eligible one still runs under the hold, where the one code path is. Tests: NOOP_MUTATORS, the deliberate inverse of LOCKED_MUTATORS, drives `test_a_read_dependent_noop_takes_no_lock` and `test_a_noop_mutation_succeeds_when_no_state_root_is_derivable` over all ten public entry points, plus `test_mutators_take_no_lock_for_a_missing_ledger`. `test_a_failing_probe_read_falls_through_to_the_locked_path` faults only the probe read, which is what keeps the under-lock no-write guards ablation-provable now that the probe answers those same inputs first — the two rewritten tests say so and point at it. 18 ablations run singly; every one reddened its intended oracle.

…aseline blob (#735)

…mitted baseline (#735)

…735, #736) CHANGELOG gains the two consolidated `### Fixed` entries: the #736 advisory pre-lock probes and the #735 blob-derived restore anchors, each naming its released-behavior delta. docs/FEATURES.md: the rollback-paths sentence now describes the restores as compare-and-set whose WRITE anchors on the committed baseline blob, with the post-reset observation authorizing only the skips, and names the degrade each site takes when no anchor can be derived. The board-lock and ledger-lock bullets both gain the relaxed invariant: the hold covers every read that decides the published bytes, and a read-dependent no-op is answered by one advisory pre-lock read that takes no lock. Two test changes the completeness audit forced, no mechanism code: - tests/test_engine.py: `test_defer_skips_restore_for_a_ledger_the_reset_never_touched` had gone VACUOUS. Its ablation ("delete the `_ledger_is_gits_to_restore` gate and the rival entry is clobbered") passed green on HEAD, because the #735 write arm is now `anchored and current == expected` and an untracked ledger has no blob at the baseline, so the arm cannot fire with or without the gate. Adds the oracle that does grade it — the gate short-circuits above the baseline probe, so above the git spawn and the lock — and rewrites the record to say why the data oracles no longer discriminate. Re-ablated: reds on `assert probed == []`. - tests/test_sprintstatus_advance.py: requalified the record in `test_a_racing_writers_flip_survives_a_concurrent_advance` that said hoisting read#1 above the lock does not redden the row. Still true, but it now describes production — the #736 probe IS that hoisted read — so it says so, and says why this row is what makes it safe.

coderabbitai · 2026-08-26T18:08:52Z

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Walkthrough

The change adds advisory no-op probes for sprint-status and deferred-ledger mutations. It changes reset-spanning ledger restores to use committed baseline or rejected-rewrite anchors, with skip, merge, or escalation for missing and divergent anchors.

Changes

Serialization and ledger restoration

Layer / File(s)	Summary
Sprint-status advisory probing `src/bmad_loop/sprintstatus.py`, `tests/test_sprintstatus_advance.py`, `docs/FEATURES.md`	`advance` probes for absent or already-satisfied rows before lock acquisition. Write decisions remain authoritative under the board lock.
Deferred-ledger batch probes `src/bmad_loop/deferredwork.py`, `tests/test_deferredwork.py`, `CHANGELOG.md`	Close, reopen, decision, append, and archive operations reuse shared helpers. Proven no-ops skip locking. Writes and probe failures use the locked path.
Committed-baseline restore anchors `src/bmad_loop/engine.py`, `src/bmad_loop/sweep.py`, `tests/test_engine.py`, `tests/test_sweep.py`, `docs/FEATURES.md`, `CHANGELOG.md`	Restore paths use committed baseline or rejected-rewrite anchors. Divergent, missing, external, and symlinked ledger cases avoid unsafe direct overwrites.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: 🔵 Low · up to b168a

The PR improves no-op locking and reset-restore anchoring, but repository-local symlinks to external ledgers may still be misclassified during restoration and some test-contract documentation may need cleanup. The change is mergeable with explicit owner follow-up on these bounded risks.

Suggested reviewers: dracic

Poem

A rabbit probed the ledger light
And skipped the lock when bytes stayed still
Git held the baseline tight
Rival writes escaped the quill
The tests marked every guarded hill

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes both primary changes: lock-free no-op handling and committed-baseline anchoring for reset-window restores. It is concise and specific.
Linked Issues check	✅ Passed	The changes satisfy `#735` by anchoring ledger restoration and migration writes to committed or rejected-rewrite content, with protection for concurrent writes and unsafe paths. The changes satisfy `#736`…
Out of Scope Changes check	✅ Passed	The source changes, documentation updates, and regression tests directly support the linked issue objectives. No unrelated code changes are evident.
Docstring Coverage	✅ Passed	Docstring coverage is 83.08% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 65 functions across 7 files.

Full details: Linked Issues check

Explanation

The changes satisfy #735 by anchoring ledger restoration and migration writes to committed or rejected-rewrite content, with protection for concurrent writes and unsafe paths. The changes satisfy #736 by adding advisory pre-lock probes for sprint-status and deferred-work no-ops while retaining authoritative locked decisions for writes and probe failures.

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Actionable comments posted: 2

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Inline comments:
In `@docs/FEATURES.md`:
- Line 39: Update the opening lock-invariant wording in the sprintstatus.advance
documentation so it no longer claims the lock covers all three reads
unconditionally; state that the lock covers the authoritative reads and write
when an advance may write, while the no-write probe occurs before the lock. Keep
the remaining explanation and behavior unchanged.

In `@src/bmad_loop/sweep.py`:
- Around line 1049-1056: The restore logic around _ledger_baseline_text must use
rewrite as the expected anchor when _ledger_is_gits_to_restore(task) returns
false for a proven external ledger, preventing the rejected rewrite from being
treated as divergence. Preserve the existing no-anchor behavior when the
baseline probe fails, and keep the ledger_lock-protected comparison unchanged.

Apply the same fix in `@CHANGELOG.md` around lines 236 - 276.

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pbean · 2026-08-26T18:16:51Z

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chatgpt-codex-connector · 2026-08-26T18:21:53Z

Codex Review: Didn't find any major issues. Nice work!

Reviewed commit: 47ad336f92

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`_ledger_rel` answers three ways on purpose — derived, fault, and proven external — but `_ledger_baseline_text` collapsed the last two into "no anchor". Proven external is determinate, not uncertain: the path resolved cleanly and still fell outside the root, so no revision of this repo can name it and `reset --hard` cannot have republished it. That is the same determinate absence as a baseline commit that lacks the path, and it now answers the same way. Both engine sites gate on `_ledger_is_gits_to_restore` before probing, so neither could reach the collapsed answer. The sweep's migration restore does not, and its own comment already claimed the not-git-owned case anchors on the rejected rewrite — for an untracked ledger inside the tree it did, via `(True, None)`; for an external one it did not. A failed migration over an `implementation_artifacts` dir configured outside the repo tree — a supported shape `ProjectPaths.rebased` deliberately leaves put — therefore stranded the half-migrated rewrite on disk and escalated with "the ledger changed underneath the failed migration attempt", which nothing had. Reported by CodeRabbit on PR #737; reproduced before the fix.

pbean · 2026-08-26T19:09:51Z

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chatgpt-codex-connector

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chatgpt-codex-connector · 2026-08-26T19:14:41Z

+            blob = verify.worktree_file_bytes_at_revision(
+                self.workspace.root, task.baseline_commit, rel
+            )


Distinguish tracked symlinks from regular ledger blobs

When deferred-work.md is itself a tracked symlink—a supported POSIX shape—this probe returns the symlink blob's payload (the target pathname), not the ledger contents read through the link. After a failed sweep migration, _safe_reset restores only the symlink and cannot revert its external target, so expected becomes that pathname while current remains the rejected rewrite; the restore therefore always reports divergence and leaves the malformed ledger for manual recovery. Detect mode 120000 and treat this as a reset-untouched ledger whose safe anchor is the rewrite that was graded, like an external ledger.

Useful? React with 👍 / 👎.

Valid, and fixed in 6a7a508b — good catch, this one is a regression this PR introduced.

Reproduced before changing anything: a tracked ledger symlinked into the repo, plus a failed sweep migration, gave sweep-migration-restore-diverged, left the half-migrated rewrite on the target, and escalated with "the ledger changed underneath the failed migration attempt". Pre-#735 the anchor was current == observed — contents against contents — which worked; the blob anchor replaced it with a pathname against contents, so it is silently never-true. Same failure mode the CRLF normalization a few lines up already exists to prevent.

Your reading of the support question is right, and stronger than stated: atomic_write_text follows symlinks by default, and its docstring says the default was chosen so "a ledger symlinked into the repo keeps being a symlink and the real file is what gets rewritten". So this is a shape the write path was designed around, not an incidental one.

Fixed via the existing verify.path_is_non_regular_at_revision rather than a bespoke 120000 check — it already answers "not mode 100644/100755" for trees, symlinks and gitlinks, and its docstring already reasons about exactly this. Kept inside the probe's existing try, so a fault still degrades to (False, None) and the no-anchor refusal is untouched. Semantics: reset --hard restores the link and cannot reach through it, so the reset republished no ledger text — determinate absence, which each caller then fills with its own anchor (the rejected rewrite, at the sweep).

Regression test added and ablated: dropping the arm reddens it on the restored-text assertion.

chatgpt-codex-connector · 2026-08-26T19:14:41Z

  created inside the window went with it. A tracked ledger absent at snapshot time is
  still never deleted, and is now answered before any lock is taken. A write or lock fault
  is journaled as `ledger-restore-failed` and preserves an in-flight pause, as before.
+- **A read-dependent no-op is answered before its lock is taken** (#736). A lock acquired for


Condense the changelog entries

Condense these two additions into terse, imperative release-note bullets and keep the detailed concurrency rationale in the commit message or behavior documentation. Together they add 44 lines of implementation narrative, examples, failure analysis, and residual limitations, which makes the changelog difficult to scan and directly violates the repository's changelog format rule.

AGENTS.md reference: AGENTS.md:L68-L68

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Partly valid — condensed in 6a7a508b, though not to imperative bullets.

The core point holds and I measured it rather than eyeballing it. Across the Unreleased section the median entry is 5 continuation lines; these two were 21 and 24, near the section maximum of 37. They are now 11 and 13 — the deep internals (per-mutator enumeration, blow-by-blow root cause, the linearization argument) moved to the commit messages and the code comments, where they already live.

I kept the user-facing behavior deltas rather than compressing them away, since those are what a reader scans for: sweep --archive with nothing eligible now exiting 0 rather than 1, and each site's degrade direction.

Declining the "imperative" half of the suggestion. AGENTS.md:68 does say "terse, scannable, imperative", but that governs body style, not the bolded headline — settled empirically over this section: 154 of 154 entries lead with a bold noun phrase and 0 with an imperative verb (A 48×, The 22×, An 6×). Rewriting these two to "Prevent …" / "Answer …" would make them the only outliers in the file. The terse/scannable half is the part that was genuinely being violated, and that is the part I applied.

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4593-4603: 🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Resolve the ledger path before classifying repository ownership.

When implementation_artifacts is a repository-local symlink to a shared external directory, ledger.relative_to(root) succeeds before the symlink target is resolved. This marks the external ledger as git-owned. The later Git baseline then describes the symlink, not the ledger contents, and can prevent the valid restore path.

Classify with resolved paths first. This matches _ledger_in_repo semantics.

Proposed fix

         ledger = self.workspace.paths.deferred_work
         root = self.workspace.root
         try:
-            return ledger.relative_to(root).as_posix(), None
-        except ValueError:
-            try:
-                return ledger.resolve().relative_to(root.resolve()).as_posix(), None
-            except (OSError, RuntimeError) as e:
-                return None, e
-            except ValueError:
-                return None, None
+            return ledger.resolve().relative_to(root.resolve()).as_posix(), None
+        except (OSError, RuntimeError) as e:
+            return None, e
+        except ValueError:
+            return None, None

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In `@src/bmad_loop/engine.py` around lines 4593 - 4603, Update the ledger
ownership classification around the deferred-work path to resolve both ledger
and repository root before attempting the relative-path check, matching
_ledger_in_repo semantics; preserve the existing return values and exception
handling while ensuring symlinks to external directories are classified as
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Outside diff comments:
In `@src/bmad_loop/engine.py`:
- Around line 4593-4603: Update the ledger ownership classification around the
deferred-work path to resolve both ledger and repository root before attempting
the relative-path check, matching _ledger_in_repo semantics; preserve the
existing return values and exception handling while ensuring symlinks to
external directories are classified as external.

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…735) Git stores a tracked symlink as a blob holding the TARGET PATHNAME, and `worktree_file_bytes_at_revision` filters on type `blob` without looking at the mode. A ledger symlinked into the repo therefore anchored on a pathname compared against ledger text — silently never-true, the same failure mode the newline normalization already guards against. That shape is supported on purpose: `atomic_write_text` follows symlinks by DEFAULT precisely so such a ledger "keeps being a symlink and the real file is what gets rewritten". `reset --hard` restores the link and cannot reach through it, so the reset republishes no ledger text there — the existing `verify.path_is_non_regular_at_revision` names exactly that shape, and it now answers determinate absence like a proven-external ledger, leaving each caller its own anchor. Reproduced before the fix, and the new test ablated against it. Also condenses the two #735/#736 changelog entries (21 and 24 continuation lines) toward the section's median of 5, per AGENTS.md's terse/scannable rule. Headlines stay bold noun phrases, which is the section's actual form in 154 of 154 entries. Both reported by codex on PR #737.

pbean · 2026-08-26T19:24:02Z

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chatgpt-codex-connector · 2026-08-26T19:28:14Z

+                # such a ledger keeps being a symlink. Determinate absence of
+                # republished text, exactly like a proven-external ledger.
+                return True, None


Do not treat symlink-target absence as reset-owned

When the tracked ledger is a symlink and another process deletes its target during the reset window, reset --hard restores only the link and does not produce the observed None. Returning (True, None) nevertheless makes both _restore_ledger and _restore_defer_ledger accept current == expected as reset-owned and rewrite the snapshot, undoing the concurrent deletion. The fresh evidence after the prior fix is that this absence anchor now reaches these two restore callers, whereas the migration caller substitutes the rejected rewrite; non-regular paths need a distinct no-reset-content result that cannot authorize those write arms.

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Valid, and fixed in b5e1938a — this was the sharpest finding on the PR. You were right on both the mechanism and the reason it only became reachable now.

Confirmed: _ledger_baseline_text answered a bool, which merged two different facts into one write authorization —

the baseline determinately has no ledger, so reset --hard deleted it and a missing file on disk is the reset's own work; and

the reset republished no text here at all (proven external, or a non-regular baseline entry), where a missing file means somebody deleted the target.

6a7a508b returned the first for the second. And your point about reachability is exactly why it mattered: a symlinked ledger is tracked, so unlike the external case it does not short-circuit at _ledger_is_gits_to_restore — it reached both engine restore arms, where None == None held and the snapshot went back over the deletion. That inverts this program's own governing rule: observation may justify a skip, never a write.

Fixed by encoding the third state rather than widening the boolean. _LedgerAnchor is now BASELINE / NO_RESET_CONTENT / NONE:

only BASELINE authorizes a reset-owned write, so both engine arms refuse the symlink case (_restore_ledger skips, _restore_defer_ledger falls to its append-only merge, which cannot destroy a rival's write);

the sweep accepts either, because it substitutes its own anchor (the rejected rewrite) and so never compares against a bare None — which is the asymmetry you identified.

New direction pin added and ablated: widening the arm back to is not NONE recreates the deleted target and reddens the test. Full suite 7002 → 7004.

`_ledger_baseline_text` answered a bool, which merged two different facts into one write authorization: * the baseline determinately has no ledger, so `reset --hard` DELETED it and a missing file on disk is the reset's own work; and * the reset republished no text here at all (proven external, or a non-regular baseline entry such as a symlink), where a missing file means somebody deleted the target. The symlink arm added in 6a7a508 returned the first for the second. A symlinked ledger IS tracked, so unlike the external case it does not short-circuit at `_ledger_is_gits_to_restore` — it reached both engine restore arms, where `None == None` then read a rival's deletion as reset-owned and wrote the snapshot back over it. That inverts this program's own rule: observation may justify a skip, never a write. `_LedgerAnchor` now carries BASELINE / NO_RESET_CONTENT / NONE. Only BASELINE authorizes a reset-owned write; the sweep accepts either, because it supplies its own anchor (the rejected rewrite) and so never compares against a bare `None`. The defer restore degrades to its append-only merge, which cannot destroy a rival's write. New direction pin ablated: widening the arm to `is not NONE` undoes the rival's deletion and reddens the test. Reported by codex on PR #737.

`_ledger_rel` tries the lexical `relative_to` before falling back to `resolve()`, and nothing in the suite said why. A reviewer proposed collapsing it to resolve-first on PR #737; the whole suite stayed green under that change, which is exactly the gap this row closes. Resolve-first regresses the #552 shape: a registered-but-not-serving WSL UNC provider raises WinError 64 on a path that is perfectly nameable lexically, so a derived rel becomes `(None, fault)`. The fault degrades then cost real behavior — the baseline anchor drops to NONE, the retraction skips, the defer restore falls to its merge, and the sweep escalates, all for a ledger sitting in an ordinary place in the repo. Ablated against that exact reorder: both assertions red.

pbean · 2026-08-26T19:44:07Z

@coderabbitai — on the outside-diff-range comment for engine.py:4593-4603 ("Resolve the ledger path before classifying repository ownership"): declining, with evidence. The premise is half right, both stated consequences are refuted, and the proposed diff would introduce a regression.

I built the shape you described — implementation_artifacts as a repo-local symlink to a shared external dir — and probed it directly:

REL:      ("_bmad-output/implementation-artifacts/deferred-work.md", None)
GITS:     False
ANCHOR:   (BASELINE, None)
DIVERGED: False      RESTORED: True

True: the lexical relative_to does succeed before any resolve, exactly as you said.
Refuted — "This marks the external ledger as git-owned": GITS is False. Git stores implementation-artifacts as a symlink blob and does not track children through it, so path_tracked says no.
Refuted — "can prevent the valid restore path": the restore completes. No divergence journaled, pre-migration text back on disk.

The proposed diff is also actively harmful. Making _ledger_rel resolve first breaks the #552 shape — a registered-but-not-serving WSL UNC provider raises WinError 64 on a path that is perfectly nameable lexically. Same probe, with your diff applied versus current:

your diff:  REL=(None, OSError(...WinError 64)),  ANCHOR=(NONE, None)
current:    REL=("_bmad-output/.../deferred-work.md", None),  ANCHOR=(BASELINE, <committed text>)

So a ledger sitting in an ordinary place inside the repo loses its anchor entirely: the retraction skips, the defer restore drops to its merge, and the sweep escalates. The lexical-first ordering is load-bearing, not stylistic.

Worth noting your suggestion passed the full suite — nothing pinned that ordering. That gap is real, so I added test_ledger_rel_derives_lexically_before_resolving in 696fdbbc, ablated against your exact reorder (both assertions red). Thanks — the finding did not land, but chasing it closed a genuine hole.

One note for the record: at that shape the anchor answers (BASELINE, None), which would be the wrong state if it ever reached a write arm. It cannot today — GITS is False, so both engine restores short-circuit before consulting it, and the sweep substitutes its own anchor either way. Left as-is rather than spending a second git probe on an unreachable path.

pbean · 2026-08-26T19:44:12Z

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coderabbitai · 2026-08-26T19:44:30Z

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@pbean Thanks for the detailed evidence. I withdraw the finding.

_ledger_rel must derive the lexical repository-relative path before it calls resolve(). In this case, lexical relativity does not imply Git ownership because path_tracked correctly returns False for children below the symlink.

The WinError 64 case also makes the ordering necessary. A resolve-first implementation would turn a usable repository-relative path into a path-resolution fault and remove the committed-baseline anchor.

The new test_ledger_rel_derives_lexically_before_resolving covers the missing invariant. The unreachable (BASELINE, None) state does not affect a write arm under the current path_tracked == False guard and sweep-specific anchor handling.

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Learnt from: pbean
URL: https://github.com/bmad-code-org/bmad-loop/pull/737

Timestamp: 2026-08-26T19:44:29.533Z
Learning: In `src/bmad_loop/engine.py`, `Engine._ledger_rel` must call lexical `Path.relative_to()` before `Path.resolve()`. A lexically repository-relative ledger can remain nameable when resolution fails with the WSL UNC WinError 64 condition. Lexical relativity does not establish Git ownership: `path_tracked` determines whether Git tracks the path, including repository-local symlinks whose children point to external directories. The regression test `test_ledger_rel_derives_lexically_before_resolving` protects this ordering.

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🧠 Learnings used

Learnt from: pbean
Repo: bmad-code-org/bmad-loop PR: 737
File: src/bmad_loop/sweep.py:1049-1056
Timestamp: 2026-08-26T19:22:01.239Z
Learning: In `src/bmad_loop/engine.py`, `Engine._ledger_rel` distinguishes a derived repository-relative ledger path, a path-resolution fault, and a proven external ledger path. `Engine._ledger_baseline_text` must preserve this distinction: a proven external ledger has a determinate absent Git baseline and returns `(True, None)`, while a probe or resolution fault returns `(False, None)`. In `src/bmad_loop/sweep.py`, migration restore then uses the rejected `rewrite` as the compare-and-set anchor only for the determinate absent-baseline case.

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chatgpt-codex-connector · 2026-08-26T19:49:35Z

 - Ledger archiving (`sweep --archive`, optionally `--before DATE` to bound by close date; `--dry-run` previews): moves closed (`status: done <ISO date>`) entries to sibling `deferred-work-archive.md` (body preserved, an `archived: <date>` marker appended), leaving an id-preserving stub (`status: done <date>` + `archived: <date>`) so grep and `closes_deferred` cross-references keep resolving and the live ledger stays proportional to open work rather than all history. The stub keeps load-bearing field lines — `gate:` (validate's closed-gate report keeps speaking), `origin:`/`source_spec:` (the harvest-replay dedupe stays status-agnostic), and the reopenable-close undo tail (a paused sweep's bundle rollback still works). Reopening an archived stub — what that rollback does — demotes its `archived:` stamp to `archived-body:` rather than dropping it: the entry is live work again, so the stamp would be a lie and its shape would strand the entry outside every future archive, but the body its close moved out is still in the archive file and that line is what a later triage follows to it. Deterministic, no LLM, atomic writes with crash-safe ordering (archive before ledger; a retry keyed on id + close date completes the move without duplicate bodies). Refuses while any engine run is live or its liveness is unverifiable — it is the one out-of-band ledger writer. When the ledger is tracked, the move is durable only once both files are committed; a gitignored ledger — the default shape — or an artifact dir outside the repo has nothing to commit. Unrelated to `bmad-loop archive <run-id>` (run-tarball archiving).
 - Sweeps are their own resumable runs (`bmad-loop resume <id>`). An escalated bundle resolves like a story escalation, including intent-gap patch-restore: `bmad-loop resolve <id> --restore-patch <path>` re-arms the bundle spec to `in-review` and the re-driven bundle session resumes review on the re-applied patch instead of re-implementing.
- Ledger writes serialize across processes (#286/#469). Every orchestrator mutation of `deferred-work.md` — an append, a close, a reopen, a recorded decision, `sweep --archive`'s two-file rewrite — holds an advisory lock for its whole read-modify-write, so a second `bmad-loop run`, a run plus a sweep, or a run plus the TUI decision modal can no longer both read, both edit, and let the last atomic write win (lost entries, silently reverted closures, two appenders minting the same `DW-<n>`); multi-row work is batched into one locked pass rather than one per row. The lock is a sidecar under the state root (`<state root>/locks/<digest>-<basename>.lock`), never beside the ledger, because the ledger is tracked by design and the engine stages with `git add -A`; it is keyed on the resolved path, so every spelling of one file contends on one lock while two worktrees' in-tree ledgers correctly get their own. Readers stay lock-free — every writer already replaces the file atomically, so a reader sees one whole version or another. The wait is platform-asymmetric: POSIX blocks, while Windows bounds it at roughly ten seconds and then surfaces contention as an error rather than proceeding unlocked. A dev or review session's own ledger writes are deliberately outside this — the orchestrator sequences its writes against the sessions it dispatches. The rollback paths that span a `git reset --hard` cannot be covered by a lock at all, so each is instead compare-and-set against the ledger as observed the instant the rollback returned, degrading to a journaled `defer-ledger-restore-diverged`, `ledger-restore-skipped-diverged` or `sweep-migration-restore-diverged` rather than writing over a concurrent writer; and a failed commit reopens exactly the entries the story itself closed, journaling `deferred-close-rolled-back` with their ids and `deferred-close-reopen-unmatched` for an entry whose undo marker a foreign edit has displaced.
+- Ledger writes serialize across processes (#286/#469). Every orchestrator mutation of `deferred-work.md` — an append, a close, a reopen, a recorded decision, `sweep --archive`'s two-file rewrite — holds an advisory lock for its whole read-modify-write, so a second `bmad-loop run`, a run plus a sweep, or a run plus the TUI decision modal can no longer both read, both edit, and let the last atomic write win (lost entries, silently reverted closures, two appenders minting the same `DW-<n>`); multi-row work is batched into one locked pass rather than one per row. The lock is a sidecar under the state root (`<state root>/locks/<digest>-<basename>.lock`), never beside the ledger, because the ledger is tracked by design and the engine stages with `git add -A`; it is keyed on the resolved path, so every spelling of one file contends on one lock while two worktrees' in-tree ledgers correctly get their own. Readers stay lock-free — every writer already replaces the file atomically, so a reader sees one whole version or another. The wait is platform-asymmetric: POSIX blocks, while Windows bounds it at roughly ten seconds and then surfaces contention as an error rather than proceeding unlocked. A dev or review session's own ledger writes are deliberately outside this — the orchestrator sequences its writes against the sessions it dispatches. Here too the hold covers every read that decides the **published bytes** rather than every read: a mutator whose work turns out to be a no-op — ids already done, a decision on an entry that is not there, specs that all dedupe, nothing eligible to archive, or no ledger at all — is answered from one advisory pre-lock read running the same pure decision helper the locked pass runs, and takes no lock (#736), so a replayed rollback or a `sweep --archive` over a ledger holding nothing closed cannot fail on a lock it had no write to serialize. Only a would-write-nothing answer is acted on; anything else, and any fault while probing, falls through to the hold. `append_entries_published` deliberately keeps no missing-ledger answer — an absent ledger there means create, which is a write. The rollback paths that span a `git reset --hard` cannot be covered by a lock at all, so each is instead compare-and-set — and the **write** is anchored on the ledger's committed blob at the run's baseline commit, the text that reset republished, read out of git before the lock rather than off a working tree a rival could have written inside the reset window (#735); the sweep's untracked ledger, which has no blob, anchors instead on the rejected rewrite the attempt itself graded. A post-reset observation still authorizes the **skips** — declining to act is safe whoever wrote those bytes — and never a write. Divergence, and an anchor no probe could derive (journaled `ledger-baseline-probe-failed`, from an unreadable blob, an external ledger or a run with no baseline commit), degrade each site in its own direction rather than writing over a concurrent writer: `defer-ledger-restore-diverged` merges by appending the entries disk has since lost, `ledger-restore-skipped-diverged` skips, and `sweep-migration-restore-diverged` escalates for a human to re-run the sweep. And a failed commit reopens exactly the entries the story itself closed, journaling `deferred-close-rolled-back` with their ids and `deferred-close-reopen-unmatched` for an entry whose undo marker a foreign edit has displaced.


Correct the documented baseline-probe outcomes

When the ledger is external or task.baseline_commit is absent, _ledger_baseline_text returns NO_RESET_CONTENT or NONE without appending ledger-baseline-probe-failed; moreover, an external ledger can still authorize the sweep restore using the rejected rewrite, while the other restore paths short-circuit when Git does not own it. This behavior reference instead classifies both cases as journaled probe failures that make every site degrade, which gives operators the wrong recovery behavior and tells them to look for an event that is never emitted. Reserve that event for actual probe/decoding faults and describe these determinate cases separately.

AGENTS.md reference: AGENTS.md:L1-L3

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Valid, fixed in 5cf58d79. Docs only — and the external half of it is stale because of the fixes earlier in this thread, so thank you for catching the knock-on.

Both claims checked against the code:

"an external ledger" — answers NO_RESET_CONTENT and journals nothing. Its journal.append sits inside if fault is not None:, so the determinate case never reaches it. And it does not make every site degrade: the sweep restore completes on the rejected rewrite; only the engine's two restores stand down.

"a run with no baseline commit" — answers NONE and returns before any journal call. That silence is deliberate, and pinned by a test asserting the event list is empty: nothing failed, so the write arm stands down rather than filing a row an operator would have to triage.

So the parenthetical was wrong twice, and your framing of the cost is the right one — it pointed operators at an event that is never emitted for two of the three causes it listed. That event is now reserved for what actually emits it: an unreadable blob or a failed path resolution.

Also widened the anchor sentence just above it, which still said "the sweep's untracked ledger". After 6a7a508b and b5e1938a that set is untracked, configured outside the repo tree, or symlinked into it — and it now also records that the engine's two restores decline to read a missing file there as the reset's own work, which is the distinction your earlier P1 forced.

Suite 7004 passed, pyright 0, trunk clean.

The ledger-lock bullet listed "an external ledger" and "a run with no baseline commit" as causes of a journaled `ledger-baseline-probe-failed` that degrades every site. Neither is true: * an external ledger answers NO_RESET_CONTENT, journals nothing, and the sweep restore still completes on the rejected rewrite — only the engine's two restores stand down; and * a run with no baseline commit answers NONE and deliberately journals nothing, so the write arm stands down silently rather than filing a row an operator would have to triage. Only an unreadable blob or a failed path resolution emit that event. As written the reference sent operators looking for a row that is never logged. The anchor sentence above it also still said "untracked", which the last two commits widened to untracked, external, or symlinked. Reported by codex on PR #737. Docs only — no behavior change.

pbean · 2026-08-26T20:05:42Z

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chatgpt-codex-connector · 2026-08-26T20:09:54Z

+            # `NO_RESET_CONTENT` anchor plus a missing file is a rival's
+            # deletion, not the reset's. The append-only merge below is the
+            # right degrade — it cannot destroy a rival's write.
+            if anchor is _LedgerAnchor.BASELINE and current == expected:


Preserve symlink-target deletions during defer restore

When the tracked ledger is a symlink and another process deletes its target during the defer reset window, this NO_RESET_CONTENT case falls through to _merge_snapshot_entries(current or "", snapshot); with current is None, every snapshot entry is considered missing and the subsequent atomic write recreates the target, undoing the concurrent deletion. Fresh evidence after the earlier symlink fix is that only the direct baseline overwrite was gated here—the append-only fallback still treats absence as content to merge over. Skip restoration when this anchor has no reset-owned content and the target is absent.

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Valid, fixed in e4dc35d3. You were right, and specifically right about what my previous fix left uncovered — I gated the direct overwrite and then asserted in the commit message that the append-only merge "cannot destroy a rival's write." That was true and beside the point.

Reproduced before changing anything: with the target unlinked, _restore_defer_ledger recreated it, holding the snapshot's DW-1.

The mechanism is exactly as you described. _merge_snapshot_entries(current or "", snapshot) turned a ledger that is GONE into a ledger where every snapshot entry is merely missing, so the merge appended them all and wrote the file back. The immunity I claimed covers a rival's WRITE only — the merge never removes anything — but resurrecting what a rival DELETED is the same overwrite wearing different clothes. And the tracked symlink is what reaches it: git owns the link, so the _ledger_is_gits_to_restore gate lets it through, while reset --hard restores the link and never the target.

Fixed slightly more broadly than "NO_RESET_CONTENT plus absent target", because the hazard is not specific to that anchor. Any path reaching the merge with current is None is a deletion this restore cannot attribute to the reset — the arm above already claims the one absence that IS the reset's own work (a baseline determinately lacking the ledger, where None == None holds and the snapshot is written). So the merge now runs only on a ledger that is actually present, and a missing one falls through to defer-ledger-restore-diverged with no ids merged. That also covers NONE (a probe fault) plus an absent file, where recreating would have been just as unprovable.

One thing your finding shook out: the new path left collided unbound in the journal call, since the merge no longer always runs. Caught immediately by the regression test — it now initializes beside merged and flat_remainder.

Ablated: restoring current or "" brings the target back and reddens. Suite 7004 → 7005, pyright 0, trunk clean.

Gating the DIRECT overwrite on a BASELINE anchor was not enough at this site, because it degrades to an append-only merge rather than to a skip. That merge is immune to a rival's WRITE — it only ever adds — but it read `current or ""`, so a ledger that is GONE looked like one where every snapshot entry is merely missing, and it wrote them all back. Recreating a file a rival deleted is the same overwrite wearing different clothes. A tracked symlink is the shape that reaches it: git owns it, so the `_ledger_is_gits_to_restore` gate lets it through, while `reset --hard` restores only the link and never the target a rival unlinked. The merge now runs only on a ledger that is actually there. A missing one falls through to the divergence journal — the arm above already claimed the single absence that IS the reset's own work, a baseline that determinately lacks the ledger. `collided` joins the other two accumulators at their pre-lock initialization, since the merge no longer always runs. Ablated: restoring `current or ""` recreates the target and reddens. Reported by codex on PR #737.

pbean · 2026-08-26T20:19:43Z

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chatgpt-codex-connector

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chatgpt-codex-connector · 2026-08-26T20:24:14Z

+                # this site supplies its own text for the no-reset-content case
+                # (`rewrite`, which it graded), so `expected` is never the bare
+                # `None` that would read a rival's deletion as the reset's work.
+                if anchor is not _LedgerAnchor.NONE and current == expected:


Accept an already-restored symlink ledger

When a failed migration replaces a tracked ledger symlink with a regular file—as atomic-save editors commonly do—reset --hard restores the symlink while leaving its external target at the original text. The resulting current is therefore already correct but differs from the rejected regular-file rewrite used as expected, so this condition reports false divergence and escalates every retry. Treat current == text as an already-completed restore before requiring the rewrite anchor.

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Valid, fixed in b168a96e. Reproduced before changing anything, and your causal chain held end to end — with no rival anywhere:

DIVERGED: True IS_SYMLINK: True TARGET_IS_LEGACY: True SESSIONS: 1

The ledger was already correct and the sweep escalated over it, spending the attempt budget so the second attempt never dispatched. This is the #736 principle showing up at the restore: an operation with nothing to write must not fail.

One correction worth recording, because your suggested phrasing — treat current == text as an already-completed restore before requiring the anchor — is too broad if taken literally, and I tried it that way first. On a BASELINE anchor the reset republishes the committed text, so current == text is the ordinary post-reset state on every tracked ledger. Accepting it there retires the divergence check and the probe-fault escalation along with it. Two existing tests caught that immediately (..._write_failure_propagates_and_keeps_the_ledger and ..._escalates_when_the_baseline_probe_fails).

So the arm is scoped to NO_RESET_CONTENT, which is precisely the situation your finding describes: only where the reset restored no text of its own is "the ledger is already correct" information the anchor cannot supply. The tracked path is byte-for-byte unchanged.

Ablated: dropping the arm journals sweep-migration-restore-diverged, restores the "changed underneath" accusation, and drops the run back to one session. Suite 7005 → 7006, pyright 0, trunk clean.

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🧹 Nitpick comments (1)

tests/test_engine.py (1)
13113-13114: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Remove the duplicated skipif decorator and correct the cross-referenced test name.

Line 13113 and line 13114 apply the same skipif marker to test_defer_restore_never_resurrects_a_deleted_symlink_target. One is enough.

The docstring at line 13171 names test_ledger_baseline_text_answers_determinate_absence. This file defines that row as test_ledger_baseline_text_reports_absence_at_baseline (line 12998), so the reference does not resolve.
🧹 Proposed fixes
-@pytest.mark.skipif(sys.platform == "win32", reason="POSIX symlinks")
 `@pytest.mark.skipif`(sys.platform == "win32", reason="POSIX symlinks")
 def test_defer_restore_never_resurrects_a_deleted_symlink_target(project, tmp_path):
-    file as proof, because only there did the reset actually delete it — which is
-    exactly what `test_ledger_baseline_text_answers_determinate_absence` pins.
+    file as proof, because only there did the reset actually delete it — which is
+    exactly what `test_ledger_baseline_text_reports_absence_at_baseline` pins.
Based on learnings, in-file ablation records are durable test-contract documentation, so the named pinning test must be accurate.

Also applies to: 13161-13178
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In `@tests/test_engine.py` around lines 13113 - 13114, Remove the duplicate skipif
decorator from test_defer_restore_never_resurrects_a_deleted_symlink_target, and
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Nitpick comments:
In `@tests/test_engine.py`:
- Around line 13113-13114: Remove the duplicate skipif decorator from
test_defer_restore_never_resurrects_a_deleted_symlink_target, and update its
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…735, #736) A restore that finds the ledger already holding the text it would write is DONE, not divergent — the #736 principle applied at the restore. Reachable with no rival at all. A migration session that atomic-saves — write-temp-then-rename, how most editors and many CLIs write — replaces a tracked symlink with a regular file. `reset --hard` puts the link back, and the external target it can never reach was therefore never rewritten, so the ledger is already correct. But `rewrite`, read off that regular file, is the rejected migration text, so demanding the anchor reported a divergence that did not happen, escalated, and spent the attempt budget: the second attempt never dispatched. Scoped to a NO_RESET_CONTENT anchor deliberately. On BASELINE the reset republishes the committed text, so `current == text` is the ORDINARY post-reset state; accepting it there retires the divergence check and the probe-fault escalation with it — which is exactly what the first, unscoped attempt did, and what two existing tests caught. Ablated: dropping the arm journals the divergence, restores the "changed underneath" accusation, and drops the run back to one session. Reported by codex on PR #737.

pbean · 2026-08-26T20:33:43Z

@codex review

chatgpt-codex-connector · 2026-08-26T20:38:01Z

Codex Review: Didn't find any major issues. Another round soon, please!

Reviewed commit: b168a96eb6

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t added 6 commits August 26, 2026 10:01

fix(sprintstatus): answer a no-op advance before taking the board lock (

94de03e

#736)

fix(engine): anchor the reset-owned ledger restore on the committed b…

b2d4331

…aseline blob (#735)

fix(engine,sweep): anchor the defer and migration restores on the com…

bf34d38

…mitted baseline (#735)

coderabbitai Bot reviewed Aug 26, 2026

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Comment thread docs/FEATURES.md Outdated

Comment thread src/bmad_loop/sweep.py Outdated

This was referenced Aug 26, 2026

advance takes the board lock before discovering a no-op, so an idempotent confirm replay can fail on contention #736

Closed

_restore_ledger: the reset_owned CAS anchor trusts a post-reset observation and can overwrite a concurrent writer #735

Closed

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t added 2 commits August 26, 2026 12:39

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#736 — a lock taken for work that will not write

#735 — a post-reset observation used as a write anchor

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