refactor: Coerce --detection-depth into number

src/cli/args.ts

@@ -68,7 +68,7 @@ export interface ArgsOptions {
   // (see the snyk-mvn-plugin or snyk-gradle-plugin)
   _doubleDashArgs: string[];
   _: MethodArgs;
-  [key: string]: boolean | string | MethodArgs | string[]; // The two last types are for compatibility only
+  [key: string]: boolean | string | number | MethodArgs | string[]; // The two last types are for compatibility only
 }
 
 export function args(rawArgv: string[]): Args {
@@ -227,6 +227,10 @@ export function args(rawArgv: string[]): Args {
     }
   }
 
+  if (argv.detectionDepth !== undefined) {
+    argv.detectionDepth = Number(argv.detectionDepth);
+  }
+
   if (argv.skipUnresolved !== undefined) {
     if (argv.skipUnresolved === 'false') {
       argv.allowMissing = false;

src/cli/index.ts

@@ -1,3 +1,4 @@
+#!/usr/bin/env node
 import 'source-map-support/register';
 import * as Debug from 'debug';
 import * as pathLib from 'path';
@@ -39,6 +40,7 @@ import {
   SupportedUserReachableFacingCliArgs,
 } from '../lib/types';
 import { SarifFileOutputEmptyError } from '../lib/errors/empty-sarif-output-error';
+import { InvalidDetectionDepthValue } from '../lib/errors/invalid-detection-depth-value';
 
 const debug = Debug('snyk');
 const EXIT_CODES = {
@@ -261,6 +263,14 @@ async function main() {
       throw new FileFlagBadInputError();
     }
 
+    if (
+      typeof args.options.detectionDepth !== 'undefined' &&
+      (args.options.detectionDepth <= 0 ||
+        Number.isNaN(args.options.detectionDepth))
+    ) {
+      throw new InvalidDetectionDepthValue();
+    }
+
     validateUnsupportedSarifCombinations(args);
 
     validateOutputFile(args.options, 'json', new JsonFileOutputBadInputError());

src/lib/errors/invalid-detection-depth-value.ts

@@ -0,0 +1,10 @@
+import { CustomError } from './custom-error';
+
+export class InvalidDetectionDepthValue extends CustomError {
+  constructor() {
+    const msg = `Unsupported value for --detection-depth flag. Expected a positive integer.`;
+    super(msg);
+    this.code = 422;
+    this.userMessage = msg;
+  }
+}