feat(session): project the inherited-history boundary into the log

A plugin owning a standalone open/close bracket cannot tell a dead marker
from a live one: an unmatched `compact/start` reads identically whether the
previous writer died mid-compaction or a compaction is running now.
`Session.firstLiveSeq` already holds that answer exactly, but only in memory.

Append the log-only `session/inherited` event at that seq from the seeded
constructor — the single waist all six seeded-start paths pass through
(resume, configured startup on a persisted id, `sessions.fork()`, a subagent
fork child, `adopt()`'s live prefix, and a bare seeded `create`). Read it
through the new `isInheritedSeq(events, seq)`.

The constructor placement means persistence needs no changes: the marker is
already in `events` when a backend captures the creation seed, so it rides
the ordinary seed path with no load-time write. It also covers fork, where
the inherited bracket's owner may still be running — the case a
persistence-layer boundary could not reach.

Activity ordering excludes the boundary through `lastActivityTime()`, since
lazy resume makes browsing a pickup and the three call sites would otherwise
float every opened session to the top of a picker or list.
This commit is contained in:
Hypatia May
2026-07-30 11:38:51 +08:00
parent 2a53806275
commit b341155652
41 changed files with 850 additions and 122 deletions

View File

@@ -23,7 +23,7 @@ export * from './types.ts'
export type { AssistantMessage, ToolResultMessage, UserMessage } from '@deepseek-ai/dsh-llm'
export { isJsonValue, snapshotJsonValue } from './json.ts'
export type { JsonValue } from './json.ts'
export { interruptedTurnClosers, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from './repair.ts'
export { interruptedTurnClosers, isInheritedSeq, lastActivityTime, TOOL_NOT_STARTED, TOOL_OUTCOME_UNKNOWN } from './repair.ts'
export { decodeStorageRecord, packChunkRuns } from './chunk-rows.ts'
export type { ChunkRow, StorageRecord } from './chunk-rows.ts'
export type { SessionSurface, SurfaceFoldReplacement, SurfaceFoldResult } from './surface.ts'
@@ -388,8 +388,12 @@ export class Session {
* log as a publication substitute (telemetry adoption) start here. Distinct
* from `header.seedLength`, the DURABLE fork-lineage boundary: a resumed
* session's constructor seed is its full stored log, while its header keeps
* the original fork value — this field is the in-process construction fact
* and is deliberately not persisted.
* the original fork value — this field is the in-process construction fact.
*
* Not persisted itself: a nonzero value is projected into the log as the
* `session/inherited` event at this seq, which is what a consumer reading
* STORED history reads. Prefer this field in-process — it is exact before
* the marker's write reaches storage.
*/
readonly firstLiveSeq: number
@@ -427,6 +431,13 @@ export class Session {
}
this.firstLiveSeq = this.log.length
this.header = snapshotSessionHeader(id, header)
// Appended here so the marker is already in `events` when a backend
// captures the creation seed: no load-time write. Re-marking is skipped
// because a cold session is resumed on first touch, so repeatedly opening
// one must not grow its log per open.
if (this.firstLiveSeq > 0 && this.log.at(-1)?.type !== 'session/inherited') {
this.append('session/inherited', {})
}
}
/** Cached immutable public snapshot of the private append-only log. */