init claude-code

services/compact/grouping.ts

@@ -0,0 +1,63 @@
+import type { Message } from '../../types/message.js'
+
+/**
+ * Groups messages at API-round boundaries: one group per API round-trip.
+ * A boundary fires when a NEW assistant response begins (different
+ * message.id from the prior assistant). For well-formed conversations
+ * this is an API-safe split point — the API contract requires every
+ * tool_use to be resolved before the next assistant turn, so pairing
+ * validity falls out of the assistant-id boundary. For malformed inputs
+ * (dangling tool_use after resume/truncation) the fork's
+ * ensureToolResultPairing repairs the split at API time.
+ *
+ * Replaces the prior human-turn grouping (boundaries only at real user
+ * prompts) with finer-grained API-round grouping, allowing reactive
+ * compact to operate on single-prompt agentic sessions (SDK/CCR/eval
+ * callers) where the entire workload is one human turn.
+ *
+ * Extracted to its own file to break the compact.ts ↔ compactMessages.ts
+ * cycle (CC-1180) — the cycle shifted module-init order enough to surface
+ * a latent ws CJS/ESM resolution race in CI shard-2.
+ */
+export function groupMessagesByApiRound(messages: Message[]): Message[][] {
+  const groups: Message[][] = []
+  let current: Message[] = []
+  // message.id of the most recently seen assistant. This is the sole
+  // boundary gate: streaming chunks from the same API response share an
+  // id, so boundaries only fire at the start of a genuinely new round.
+  // normalizeMessages yields one AssistantMessage per content block, and
+  // StreamingToolExecutor interleaves tool_results between chunks live
+  // (yield order, not concat order — see query.ts:613). The id check
+  // correctly keeps `[tu_A(id=X), result_A, tu_B(id=X)]` in one group.
+  let lastAssistantId: string | undefined
+
+  // In a well-formed conversation the API contract guarantees every
+  // tool_use is resolved before the next assistant turn, so lastAssistantId
+  // alone is a sufficient boundary gate. Tracking unresolved tool_use IDs
+  // would only do work when the conversation is malformed (dangling tool_use
+  // after resume-from-partial-batch or max_tokens truncation) — and in that
+  // case it pins the gate shut forever, merging all subsequent rounds into
+  // one group. We let those boundaries fire; the summarizer fork's own
+  // ensureToolResultPairing at claude.ts:1136 repairs the dangling tu at
+  // API time.
+  for (const msg of messages) {
+    if (
+      msg.type === 'assistant' &&
+      msg.message.id !== lastAssistantId &&
+      current.length > 0
+    ) {
+      groups.push(current)
+      current = [msg]
+    } else {
+      current.push(msg)
+    }
+    if (msg.type === 'assistant') {
+      lastAssistantId = msg.message.id
+    }
+  }
+
+  if (current.length > 0) {
+    groups.push(current)
+  }
+  return groups
+}