fix: extra error handling and debugging [IAC-3138]

src/cli/commands/test/iac/scan.ts

@@ -1,5 +1,6 @@
 import * as cloneDeep from 'lodash.clonedeep';
 import * as assign from 'lodash.assign';
+import * as debugLib from 'debug';
 
 import {
   IacFileInDirectory,
@@ -30,6 +31,8 @@ import { getRepositoryRootForPath } from '../../../../lib/iac/git';
 import { getInfo } from '../../../../lib/project-metadata/target-builders/git';
 import { buildMeta, GitRepository, GitRepositoryFinder } from './meta';
 
+const debug = debugLib('snyk-iac');
+
 export async function scan(
   iacOrgSettings: IacOrgSettings,
   options: any,
@@ -109,6 +112,7 @@ export async function scan(
         iacScanFailures = [...iacScanFailures, ...(failures || [])];
         iacIgnoredIssuesCount += ignoreCount;
       } catch (error) {
+        debug(`Scan error for path ${path}: ${error}`);
         res = formatTestError(error);
       }
 
@@ -161,6 +165,8 @@ function formatTestError(error) {
   } else if (typeof error !== 'object') {
     errorResponse = new Error(error);
   } else {
+    // we should not get here, but if we do, we want to log the thrown object
+    debug('Unexpected error object:', safeStringify(error));
     try {
       errorResponse = JSON.parse(error.message);
     } catch (unused) {
@@ -170,6 +176,17 @@ function formatTestError(error) {
   return errorResponse;
 }
 
+function safeStringify(obj: unknown): string {
+  try {
+    return JSON.stringify(obj);
+  } catch (e) {
+    if (e instanceof Error) {
+      return `Error stringifying object: ${e.message}`;
+    }
+    return `Error stringifying object`;
+  }
+}
+
 class CurrentWorkingDirectoryTraversalError extends CustomError {
   public filename: string;
   public projectRoot: string;

src/lib/snyk-test/iac-test-result.ts

@@ -1,6 +1,9 @@
 import pick = require('lodash.pick');
 import { CustomError } from '../errors';
 import { BasicResultData, SEVERITY, TestDepGraphMeta } from './legacy';
+import * as debugLib from 'debug';
+
+const debug = debugLib('snyk-iac');
 
 export interface AnnotatedIacIssue {
   id: string;
@@ -58,10 +61,24 @@ const IAC_ISSUES_KEY = 'infrastructureAsCodeIssues';
 export function mapIacTestResult(
   iacTest: IacTestResponse,
 ): MappedIacTestResponse | IacTestError {
-  if (iacTest instanceof CustomError) {
+  if (iacTest instanceof Error) {
     return mapIacTestError(iacTest);
   }
 
+  if (!iacTest.result) {
+    // This is an unexpected scenario, we should always have a result object,
+    // but if we don't, we should handle it gracefully.
+    debug(`invalid scan result: ${iacTest}`);
+    const errorMessage = iacTest.path
+      ? `Invalid result for ${iacTest.path}`
+      : 'Invalid result';
+    return mapIacTestError(
+      new CustomError(
+        `${errorMessage}. Please run the command again with the \`-d\` flag and contact [email protected] with the contents of the output`,
+      ),
+    );
+  }
+
   const infrastructureAsCodeIssues =
     iacTest?.result?.cloudConfigResults.map(mapIacIssue) || [];
   const {
@@ -76,10 +93,10 @@ export function mapIacTestResult(
   };
 }
 
-export function mapIacTestError(error: CustomError) {
+export function mapIacTestError(error: Error) {
   return {
     ok: false,
-    code: error.code,
+    code: error instanceof CustomError ? error.code : undefined,
     error: error.message,
     path: (error as any).path,
   };