fix: use consistent message for JSON.parse() errors

lib/chain-error.ts

@@ -0,0 +1,33 @@
+/**
+ * (C) Copyright IBM Corp. 2023.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Given two Error instances 'error' and 'causedBy', this function will
+ * update 'error' by chaining 'causedBy' to it.
+ * Specifically, 'causedBy''s message and stack will be appended
+ * to 'error''s message and stack, respectively, to simulate chained Errors.
+ *
+ * @param error the Error object to be updated
+ * @param causedBy an Error object that represents the cause of 'error'
+ * @returns 'error' after updating its message and stack fields
+ */
+export function chainError(error: Error, causedBy: Error): Error {
+  error.message += ` ${causedBy.toString()}`;
+  if (causedBy.stack) {
+    error.stack += `\nCaused by: ${causedBy.stack}`;
+  }
+  return error;
+}

lib/request-wrapper.ts

@@ -36,6 +36,7 @@ import {
 import logger from './logger';
 import { streamToPromise } from './stream-to-promise';
 import { CookieInterceptor } from './cookie-support';
+import { chainError } from './chain-error';
 
 /**
  * Retry configuration options.
@@ -577,9 +578,9 @@ function ensureJSONResponseBodyIsObject(response: any): any | string {
   try {
     dataAsObject = JSON.parse(response.data);
   } catch (e) {
-    logger.error('Response body was supposed to have JSON content but JSON parsing failed.');
-    logger.error(`Malformed JSON string: ${response.data}`);
-    throw e;
+    logger.verbose('Response body was supposed to have JSON content but JSON parsing failed.');
+    logger.verbose(`Malformed JSON string: ${response.data}`);
+    throw chainError(new Error('Error processing HTTP response:'), e);
   }
 
   return dataAsObject;

test/unit/request-wrapper.test.js

@@ -59,6 +59,7 @@ const requestWrapperInstance = new RequestWrapper();
 const warnLogSpy = jest.spyOn(logger, 'warn').mockImplementation(() => {});
 const errorLogSpy = jest.spyOn(logger, 'error').mockImplementation(() => {});
 const debugLogSpy = jest.spyOn(logger, 'debug').mockImplementation(() => {});
+const verboseLogSpy = jest.spyOn(logger, 'verbose').mockImplementation(() => {});
 
 describe('axios', () => {
   let env;
@@ -706,14 +707,14 @@ describe('sendRequest', () => {
     mockAxiosInstance.mockResolvedValue(axiosResolveValue);
 
     await expect(requestWrapperInstance.sendRequest(parameters)).rejects.toThrow(
-      'Unexpected end of JSON input'
+      'Error processing HTTP response: SyntaxError: Unexpected end of JSON input'
     );
-    expect(errorLogSpy).toHaveBeenCalledTimes(2);
-    expect(errorLogSpy.mock.calls[0][0]).toBe(
+    expect(verboseLogSpy).toHaveBeenCalledTimes(2);
+    expect(verboseLogSpy.mock.calls[0][0]).toBe(
       'Response body was supposed to have JSON content but JSON parsing failed.'
     );
-    expect(errorLogSpy.mock.calls[1][0]).toBe('Malformed JSON string: {"key": "value"');
-    errorLogSpy.mockClear();
+    expect(verboseLogSpy.mock.calls[1][0]).toBe('Malformed JSON string: {"key": "value"');
+    verboseLogSpy.mockClear();
   });
 
   // Need to rewrite this to test instantiation with userOptions
@@ -754,6 +755,7 @@ describe('formatError', () => {
     warnLogSpy.mockClear();
     errorLogSpy.mockClear();
     debugLogSpy.mockClear();
+    verboseLogSpy.mockClear();
   });
 
   const basicAxiosError = {
@@ -967,12 +969,12 @@ describe('formatError', () => {
 
     expect(() => {
       requestWrapperInstance.formatError(newAxiosError);
-    }).toThrow('Unexpected end of JSON input');
-    expect(errorLogSpy).toHaveBeenCalledTimes(2);
-    expect(errorLogSpy.mock.calls[0][0]).toBe(
+    }).toThrow('Error processing HTTP response: SyntaxError: Unexpected end of JSON input');
+    expect(verboseLogSpy).toHaveBeenCalledTimes(2);
+    expect(verboseLogSpy.mock.calls[0][0]).toBe(
       'Response body was supposed to have JSON content but JSON parsing failed.'
     );
-    expect(errorLogSpy.mock.calls[1][0]).toBe(
+    expect(verboseLogSpy.mock.calls[1][0]).toBe(
       'Malformed JSON string: { "errorMessage": "some error"'
     );
   });
@@ -992,6 +994,7 @@ describe('gzipRequestBody', () => {
     gzipSpy.mockClear();
     errorLogSpy.mockClear();
     debugLogSpy.mockClear();
+    verboseLogSpy.mockClear();
   });
 
   it('should return unaltered data if encoding header is already set to gzip', async () => {