feat(compact): move pairing helpers (PR1 round 1)

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Hypatia May
2026-07-15 13:22:44 +08:00
parent 34bb75b2d2
commit cc546c4580
17 changed files with 525 additions and 376 deletions

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@@ -6,7 +6,7 @@ This package is the interface tier of the compaction capability, split so each c
| Package | Role |
|---|---|
| `@deepseek-ai/dsh-compact` (this) | the interface: abstract service + `compact/*` events + `CompactionResult` + the shared transcript renderer (`renderTranscript`/`renderContentBlocks`) |
| `@deepseek-ai/dsh-compact` (this) | the interface: abstract service + `compact/*` events + `CompactionResult` + tool-pairing boundary helpers + the shared transcript renderer (`renderTranscript`/`renderContentBlocks`) |
| `@deepseek-ai/dsh-compact-basic` | a backend: chars-per-token estimation (`charsPerToken`, default 4) + token-budget retention + `llm.stream()` summarization |
| `@deepseek-ai/dsh-tool-compact` (deferred) | the model-facing `/compact` tool over `ctx.compact` |
@@ -23,6 +23,12 @@ Both methods are **abstract** — the backend owns the entire strategy (token es
`compactIfNeeded` takes a required `signal`; `compactRegion`'s is optional. A backend that summarizes via `ctx.llm.stream()` **must** forward it into the call's `GenerateOptions.signal`, so an abort or fiber dispose tears down the in-flight summarization instead of leaving an orphaned model call running past the cancellation. The session being compacted comes from the agent context; the turn that the `compact/*` events belong to is recoverable from the log (the currently-open turn), so the backend stamps it from the log rather than trusting a caller-supplied value.
## Tool-pairing boundaries
The interface exports `toolPairingBalancedBefore(session, node)` and `toolPairingBalancedAfter(session, node)` for snapping and validating compaction edges. A safe edge has no unanswered assistant tool call crossing it. Each helper validates the node's seq against current surface membership and resolves the trailing edge from its cached positional successor, so a stale caller-held `node.next` cannot choose the cut.
The private per-session cache is keyed by `session.surface.replaceGeneration` and the processed surface-node count. An unchanged generation extends the fold with unseen tail nodes only; a log-only append with no new surface node does no event reads, while a replacement generation rebuilds current membership, successors, and balances. Missing event seqs and a `tool/result` without a preceding open call reject as corrupt surface state.
## Surface contract
`SurfaceEventType` is a closed union — only `user/message`, `assistant/message`, `tool/result`, `context/message`, and `steering/message` may carry `surfaceOp`. A `compact/*` event therefore **cannot** appear on the surface. A successful compaction instead: