Function checkUndefinedVariables

packages/cli/src/utils/analysis.ts:285–320

* Check for variables used but never defined.

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

 * Check for variables used but never defined.
 */
function checkUndefinedVariables(dag: BlockDependencyDag, blockMap: Map<string, BlockInfo>): LintIssue[] {
  const issues: LintIssue[] = []

  // Collect all defined variables
  const definedVars = new Set<string>()
  for (const node of dag.nodes) {
    for (const v of node.outputVariables) {
      definedVars.add(v)
    }
  }

  // Check each block's input variables
  for (const node of dag.nodes) {
    const info = blockMap.get(node.id)
    if (!info) continue

    for (const inputVar of node.inputVariables) {
      // Skip built-in variables and common globals
      if (isBuiltinOrGlobal(inputVar)) continue

      if (!definedVars.has(inputVar)) {
        issues.push({
          severity: 'error',
          code: 'undefined-variable',
          message: `Variable "${inputVar}" is used but never defined`,
          blockId: node.id,
          blockLabel: info.label,
          notebookName: info.notebookName,
          details: { variable: inputVar },
        })
      }
    }
  }

  return issues
}

/**
 * Check for circular dependencies between blocks.