Function compactViaReactive

src/commands/compact/compact.ts:140–229

(
  messages: Message[],
  context: ToolUseContext,
  customInstructions: string,
  reactive: NonNullable<typeof reactiveCompact>,
)

}

async function compactViaReactive(
  messages: Message[],
  context: ToolUseContext,
  customInstructions: string,
  reactive: NonNullable<typeof reactiveCompact>,
): Promise<{
  type: 'compact'
  compactionResult: CompactionResult
  displayText: string
}> {
  context.onCompactProgress?.({
    type: 'hooks_start',
    hookType: 'pre_compact',
  })
  context.setSDKStatus?.('compacting')

  try {
    // Hooks and cache-param build are independent — run concurrently.
    // getCacheSharingParams walks all tools to build the system prompt;
    // pre-compact hooks spawn subprocesses. Neither depends on the other.
    const [hookResult, cacheSafeParams] = await Promise.all([
      executePreCompactHooks(
        { trigger: 'manual', customInstructions: customInstructions || null },
        context.abortController.signal,
      ),
      getCacheSharingParams(context, messages),
    ])
    const mergedInstructions = mergeHookInstructions(
      customInstructions,
      hookResult.newCustomInstructions,
    )

    context.setStreamMode?.('requesting')
    context.setResponseLength?.(() => 0)
    context.onCompactProgress?.({ type: 'compact_start' })

    const outcome = await reactive.reactiveCompactOnPromptTooLong(
      messages,
      cacheSafeParams,
      { customInstructions: mergedInstructions, trigger: 'manual' },
    )

    if (!outcome.ok) {
      // The outer catch in `call` translates these: aborted → "Compaction
      // canceled." (via abortController.signal.aborted check), NOT_ENOUGH →
      // re-thrown as-is, everything else → "Error during compaction: …".
      switch (outcome.reason) {
        case 'too_few_groups':
          throw new Error(ERROR_MESSAGE_NOT_ENOUGH_MESSAGES)
        case 'aborted':
          throw new Error(ERROR_MESSAGE_USER_ABORT)
        case 'exhausted':
        case 'error':
        case 'media_unstrippable':
          throw new Error(ERROR_MESSAGE_INCOMPLETE_RESPONSE)
      }
    }