shadow.ts

/**
 * @fileoverview Shadow-bin detection. A "shadow bin" is a binary
 * exposed by a transitively-installed `node_modules/.bin` directory
 * rather than the system installation. Callers (`findRealBin`)
 * deliberately walk past these to find the real interpreter.
 */

/**
 * Check if a directory path contains any shadow bin patterns.
 *
 * @example
 * ```typescript
 * isShadowBinPath('/tmp/project/node_modules/.bin')  // true
 * isShadowBinPath('/usr/local/bin')                   // false
 * ```
 */
export function isShadowBinPath(dirPath: string | undefined): boolean {
  if (!dirPath) {
    return false
  }
  // Check for node_modules/.bin pattern (Unix and Windows)
  const normalized = dirPath.replace(/\\/g, '/')
  return normalized.includes('node_modules/.bin')
}