Master removed the stdio demo (#702c8cc30) — accept the deletion; this
branch's packChunks passthrough survives in acp-demo (auto-merged), and
cli-demo/tui-demo arrived from master without one (the follow-up snapshot
PR decides which demos expose the switch). Generated catalogs regenerated
over merged sources; the hand-written session.md durability paragraph
re-weaves this branch's lossless-encoding wording with master's invariant-
companion sentence.
Master's Zstandard physical encoding (#416) and this branch's packed chunk
rows compose as orthogonal layers: packChunks shapes the logical storage
records, compression shapes the physical bytes. The backend keeps both
config keys; eventLines(events, packChunks) replaces master's singular
eventLine helper and feeds encodeMaterialization/encodeEventBatch so packed
rows flow through either encoding. Demo apps carry both passthroughs. The
packed-row layout tests pin compression: 'none' (they assert textual line
tags) and read through rawLogPath; zstd spec fixtures inline
JSON.stringify for verbatim lines.
Conflicts: the two generated catalog docs (regenerated over merged sources)
and the jsonl backend README storage-layout bullets — master's required
delegationDepth header field weaves with this branch's storage-record/packed
row wording.
Conflicts: the four generated catalog docs (regenerated over merged sources),
session index.ts exports (keep chunk-rows exports + master's SessionSurface
re-export), stdio/acp demo config schema and persistence wiring (thread
packChunks through master's DEFAULT_PERSISTENCE_ROOT/UI shape), stdio README
config table, and the jsonl spec import line. The packed-chunk fixture also
gains the provenance field master made required on assistant/message.
A subagent child's recursion depth lived only in runtime AgentOptions,
so a persisted child came back from resume counted as top-level and
maxDepth stopped binding after every restart. Add
SessionHeader.delegationDepth, round-trip it through the JSONL and
SQLite backends (SQLite schema v5), restore it on agent-loop resume,
and write it when the in-process backends create a child. The seam now
owns the shared depth vocabulary (delegationDepthOf): the persisted
header is authoritative and monotone — runtime options may deepen it
but never lower it.
Declare MoveFileExW's return value as Koffi int and model it as a numeric 32-bit Win32 BOOL. The previous Koffi bool declaration represented a one-byte C boolean and could read the native return register with the wrong ABI.
Test zero and nonzero results explicitly and assert the binding result type while preserving the existing write-through flags, error translation, and durable directory race behavior.
Providers stream token-sized deltas, so a session log stores hundreds of
near-identical assistant/chunk lines whose JSON envelopes dwarf their
payloads (~56x measured on a real DeepSeek session, 73% of file bytes).
Add a lossless storage codec to dsh-session: packChunkRuns() folds each
run of >=3 consecutive same-block delta chunks into one storage row --
text-chunks / reasoning-chunks / tool-call-chunks, bare slash-less tags
like the header line's 'session' so rows cannot be confused with session
events -- and decodeStorageRecord() expands rows back to the exact
original events (seq0/time0 + dt gap array reconstruct every member's
seq/time; tool-call rows carry the run-constant id/name). The encoder
whitelists exact shapes and stores anything unrecognized verbatim; the
decoder validates row-tagged values and fails loud on malformation.
The JSONL backend gains a packChunks config (default false). Writing
packs only when enabled -- default-off output stays byte-identical to
the previous layout, so snapshot goldens are untouched. Reading is
layout-blind: scanLog always decodes rows and now checks seq contiguity
with a cursor instead of the line index, so packed, unpacked, and mixed
files all load identically. Fixture readers (llm-replay parseSessionLog,
acp-snapshot normalizeSessionLog) share the codec; the normalizer zeroes
a row's time0/dt exactly like an event's time. The two demo bundles
plumb packChunks from cordis.yml to the backend.
Measured on a real coding session: 105 KB -> 42 KB (-60%), 475 lines ->
74, with reasoning/tool-call heavy sessions saving the most. Covered by
example + fast-check round-trip codec tests, backend packed/mixed/torn-
tail specs, and an end-to-end demo run loading a packed log through a
default-config backend.
