Function outputDagDownstream

packages/cli/src/commands/dag.ts:408–471

(
  dag: BlockDependencyDag,
  _blocks: DeepnoteBlock[],
  blockMap: BlockMap,
  options: DagDownstreamOptions
)

}

function outputDagDownstream(
  dag: BlockDependencyDag,
  _blocks: DeepnoteBlock[],
  blockMap: BlockMap,
  options: DagDownstreamOptions
): void {
  // Find the block by ID or label
  const blockId = findBlockId(options.block, dag.nodes, blockMap)

  if (!blockId) {
    if (options.output === 'json') {
      outputJson({ success: false, error: `Block not found: ${options.block}` })
    } else {
      logError(`Block not found: ${options.block}`)
    }
    throw new DagHandledError(ExitCode.InvalidUsage)
  }

  const downstreamIds = getDownstreamBlocksForBlocksIds(dag, [blockId])
  const sourceInfo = blockMap.get(blockId)

  if (options.output === 'json') {
    outputJson({
      source: {
        id: blockId,
        label: sourceInfo?.label ?? blockId,
        type: sourceInfo?.type ?? 'unknown',
        notebook: sourceInfo?.notebookName ?? 'unknown',
      },
      downstream: downstreamIds.map(id => {
        const info = blockMap.get(id)
        return {
          id,
          label: info?.label ?? id,
          type: info?.type ?? 'unknown',
          notebook: info?.notebookName ?? 'unknown',
        }
      }),
      count: downstreamIds.length,
    })
    return
  }

  const c = getChalk()

  // Text output
  const sourceLabel = sourceInfo?.label ?? blockId
  output(`${c.bold('Downstream Impact')} for ${c.cyan(sourceLabel)}`)
  output('')

  if (downstreamIds.length === 0) {
    output(c.dim('No downstream blocks depend on this block.'))
    return
  }

  output(`${c.yellow(downstreamIds.length)} block${downstreamIds.length === 1 ? '' : 's'} will need to re-run:`)
  output('')