Function diagnoseBlockFailure

packages/cli/src/utils/analysis.ts:760–795

(
  blockId: string,
  dag: BlockDependencyDag,
  lintResult: LintResult,
  blockMap: Map<string, BlockInfo>
)

 * Diagnose why a block might have failed by analyzing its dependencies.
 */
export function diagnoseBlockFailure(
  blockId: string,
  dag: BlockDependencyDag,
  lintResult: LintResult,
  blockMap: Map<string, BlockInfo>
): FailureDiagnosis {
  const node = dag.nodes.find(n => n.id === blockId)
  const info = blockMap.get(blockId)

  // Find upstream blocks (blocks that this block depends on)
  const upstream: UpstreamBlock[] = []
  const incomingEdges = dag.edges.filter(e => e.to === blockId)

  for (const edge of incomingEdges) {
    const sourceNode = dag.nodes.find(n => n.id === edge.from)
    const sourceInfo = blockMap.get(edge.from)
    if (sourceNode && sourceInfo) {
      upstream.push({
        id: edge.from,
        label: sourceInfo.label,
        variables: sourceNode.outputVariables.filter(v => node?.inputVariables.includes(v) ?? false),
      })
    }
  }

  // Find lint issues related to this block
  const relatedIssues = lintResult.issues.filter(issue => issue.blockId === blockId)

  return {
    blockId,
    blockLabel: info?.label ?? blockId,
    upstream,
    relatedIssues,
    usedVariables: node?.inputVariables ?? [],
  }
}

/**
 * Build a block map from a DeepnoteFile for use with diagnosis functions.