Add CLI command typo detection (#34836)

[MitchLewis930]

User description

PR_040

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PR Type

Enhancement, Tests

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Description

• Add CLI command typo detection using Levenshtein distance algorithm

• Detect and suggest corrections for mistyped Next.js commands

• Export commands object for typo detection module access

• Add comprehensive integration tests for typo detection

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Diagram Walkthrough

flowchart LR
  A["User enters typo<br/>e.g., 'buidl'"] --> B["getProjectDir detects<br/>invalid input"]
  B --> C["detectTypo calculates<br/>Levenshtein distance"]
  C --> D["Match found<br/>distance ≤ 2"]
  D --> E["Suggest correction<br/>Did you mean 'build'?"]
  E --> F["Exit with error"]

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File Walkthrough

	Relevant files
Enhancement	detect-typo.ts Implement typo detection with Levenshtein distance              packages/next/lib/detect-typo.ts Implement minDistance function using dynamic programming to calculate Levenshtein distance Implement detectTypo function to find closest matching command within threshold Filter and sort potential typos by distance, returning best match or null +44/-0    get-project-dir.ts Integrate typo detection into directory validation              packages/next/lib/get-project-dir.ts Import commands object and detectTypo function Add typo detection logic when directory is not found Display helpful error message suggesting correct command Exit process when typo is detected +13/-0    next.ts Export commands object for module access                                  packages/next/bin/next.ts Export commands object to make it accessible to other modules Enable typo detection module to access available CLI commands +1/-1
Tests	index.test.js Add integration tests for typo detection                                  test/integration/cli/test/index.test.js Add new test case detects command typos with multiple typo scenarios Test typos for common commands: build, export, start, dev Verify error messages suggest correct commands Validate typo detection works across various misspellings +20/-0

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[qodo-code-review]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
⚪	Algorithmic complexity Description: The Levenshtein implementation in minDistance() runs in O(m*n) time with no early-exit/short-circuit despite accepting a threshold parameter, so a very long user-controlled input (propagated from CLI args via getProjectDir()) can cause excessive CPU/memory usage (algorithmic complexity DoS). detect-typo.ts [1-28] Referred Code // the minimum number of operations required to convert string a to string b. function minDistance(a: string, b: string, threshold: number): number { const m = a.length const n = b.length if (m < n) { return minDistance(b, a, threshold) } if (n === 0) { return m } let previousRow = Array.from({ length: n + 1 }, (_, i) => i) for (let i = 0; i < m; i++) { const s1 = a[i] let currentRow = [i + 1] for (let j = 0; j < n; j++) { const s2 = b[j] const insertions = previousRow[j + 1] + 1 ... (clipped 7 lines)
Ticket Compliance
⚪	🎫 No ticket provided Create ticket/issue
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
⚪	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Hard process exit: The new typo-detection path terminates via process.exit(1) inside getProjectDir, which may prevent callers from handling the error and can be non-graceful depending on runtime context. Referred Code if (typeof dir === 'string') { const detectedTypo = detectTypo(dir, Object.keys(commands)) if (detectedTypo) { Log.error( `"next ${dir}" does not exist. Did you mean "next ${detectedTypo}"?` ) process.exit(1) } Learn more about managing compliance generic rules or creating your own custom rules

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🟡 - Partial Compliant
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⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
High-level	Relocate command typo detection logic Move the command typo detection logic from the getProjectDir function to the main command dispatcher in packages/next/bin/next.ts. This separates command parsing from directory handling. Examples: packages/next/lib/get-project-dir.ts [23-41] if (err.code === 'ENOENT') { if (typeof dir === 'string') { const detectedTypo = detectTypo(dir, Object.keys(commands)) if (detectedTypo) { Log.error( `"next ${dir}" does not exist. Did you mean "next ${detectedTypo}"?` ) process.exit(1) } ... (clipped 9 lines) Solution Walkthrough: Before: // in 'packages/next/lib/get-project-dir.ts' export function getProjectDir(dir?: string) { try { // ... try to resolve directory } catch (err: any) { if (err.code === 'ENOENT') { // If directory not found, check if it was a command typo const detectedTypo = detectTypo(dir, Object.keys(commands)) if (detectedTypo) { Log.error(`Did you mean "next ${detectedTypo}"?`) process.exit(1) } // ... otherwise, it's a real missing directory Log.error(`Invalid project directory provided...`) process.exit(1) } throw err } } After: // in 'packages/next/bin/next.ts' const command = argv._[0] if (commands[command]) { // ... execute valid command } else { // Handle unknown command before treating it as a directory const detectedTypo = detectTypo(command, Object.keys(commands)); if (detectedTypo) { log.error(`Did you mean "next ${detectedTypo}"?`); process.exit(1); } // ... then proceed with original unknown command/directory logic log.error('Unknown command:', command); process.exit(1); } Suggestion importance[1-10]: 9 __ Why: This suggestion correctly identifies a significant design flaw, where command typo detection is improperly coupled with file system error handling, and proposes a much cleaner, more robust architectural solution.	High
General	Make typo detection case-insensitive Make typo detection case-insensitive by converting both the user input and the command options to lowercase before calculating the distance. packages/next/lib/detect-typo.ts [31-44] export function detectTypo(input: string, options: string[], threshold = 2) { + const normalizedInput = input.toLowerCase() const potentialTypos = options .map((o) => ({ option: o, - distance: minDistance(o, input, threshold), + distance: minDistance(o.toLowerCase(), normalizedInput, threshold), })) .filter(({ distance }) => distance <= threshold && distance > 0) .sort((a, b) => a.distance - b.distance) if (potentialTypos.length) { return potentialTypos[0].option } return null } Apply / Chat Suggestion importance[1-10]: 7 __ Why: This is a valuable improvement that makes the typo detection case-insensitive, which is the expected behavior for CLI commands, thus enhancing the feature's robustness.	Medium
	Remove unused function parameter Remove the unused threshold parameter from the minDistance function signature and its recursive call, as it is not used in the function's logic. packages/next/lib/detect-typo.ts [2-8] // the minimum number of operations required to convert string a to string b. -function minDistance(a: string, b: string, threshold: number): number { +function minDistance(a: string, b: string): number { const m = a.length const n = b.length if (m < n) { - return minDistance(b, a, threshold) + return minDistance(b, a) } ... [To ensure code accuracy, apply this suggestion manually] Suggestion importance[1-10]: 5 __ Why: The suggestion correctly identifies that the threshold parameter in minDistance is unused, and removing it is a valid way to clean up the code.	Low
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