agentsqripts/lib/utils/pattern-detector/conditions/hasEarlyExit.js

Comprehensive static code analysis toolkit for identifying technical debt, security vulnerabilities, performance issues, and code quality problems

/**
 * @file Check for early exit conditions in code blocks
 * @description Single responsibility: Detect control flow statements that exit early
 * 
 * This utility analyzes code blocks to identify early exit conditions that affect
 * control flow analysis. It's essential for performance and complexity analysis,
 * helping determine if loops or functions have early termination conditions that
 * impact algorithmic complexity calculations.
 * 
 * Design rationale:
 * - Focuses on control flow statements that change execution path
 * - Uses regex pattern matching for reliable keyword detection
 * - Boundary checking prevents array index errors
 * - Conservative approach includes all relevant exit mechanisms
 */

/**
 * Analyze code lines for early exit control flow statements
 * 
 * Technical function: Scans specified line range for keywords that cause early exit
 * 
 * Implementation rationale:
 * - Math.max/Math.min provide robust boundary protection against invalid indices
 * - Regular expression matches common early exit patterns efficiently
 * - Sequential scanning allows early return optimization for performance
 * - Covers both JavaScript and Node.js specific exit mechanisms
 * 
 * Control flow analysis strategy:
 * - 'break': Exits loops early, affects complexity analysis
 * - 'return': Exits functions early, critical for algorithm analysis
 * - 'continue': Skips loop iterations, affects performance patterns
 * - 'throw': Exception-based early exit, impacts error handling analysis
 * - 'process.exit': Node.js application termination, critical for server analysis
 * 
 * Pattern matching considerations:
 * - Regex uses word boundaries implicitly through context
 * - No word boundary anchors used to catch partial matches (e.g., in strings)
 * - Case-sensitive matching for JavaScript keyword precision
 * - Escaped dot in 'process\.exit' prevents wildcard matching
 * 
 * Performance optimization:
 * - Early return when first match found (short-circuit evaluation)
 * - O(n) time complexity where n is number of lines in range
 * - Regex compilation happens once and is cached by JavaScript engine
 * - Boundary calculation done once before loop starts
 * 
 * Boundary handling:
 * - Negative startIndex safely clamped to 0
 * - endIndex beyond array length safely clamped to array.length
 * - Empty ranges (start >= end) return false without error
 * - Invalid array input would cause TypeError (intended behavior)
 * 
 * Limitations and trade-offs:
 * - String matching may have false positives in comments or string literals
 * - Doesn't parse JavaScript AST for perfect accuracy (trade-off for performance)
 * - Conservative approach may flag legitimate uses in strings
 * - Simple pattern matching chosen over complex parsing for reliability
 * 
 * Alternative approaches considered:
 * - AST parsing: Rejected for performance overhead in pattern detection
 * - Individual string.includes checks: Rejected as less efficient than single regex
 * - Complete tokenization: Rejected as overkill for this specific detection
 * 
 * @param {string[]} lines - Array of code lines to analyze
 * @param {number} startIndex - Starting line index (inclusive, will be clamped to valid range)
 * @param {number} endIndex - Ending line index (exclusive, will be clamped to valid range)
 * @returns {boolean} True if any early exit pattern found within specified range
 * @example
 *   hasEarlyExit(['if (x) {', '  return false;', '}'], 0, 3) // returns true
 *   hasEarlyExit(['for (let i = 0; i < 10; i++) {', '  if (found) break;', '}'], 1, 2) // returns true
 */
function hasEarlyExit(lines, startIndex, endIndex) {
  const start = Math.max(0, startIndex);
  const end = Math.min(lines.length, endIndex);
  
  for (let i = start; i < end; i++) {
    if (/break|return|continue|throw|process\.exit/.test(lines[i])) {
      return true;
    }
  }
  
  return false;
}

module.exports = hasEarlyExit;