core: filter out duplicate error messages

lib/common/util.js

@@ -33,6 +33,7 @@ var request = require('request').defaults({
 });
 var retryRequest = require('retry-request');
 var through = require('through2');
+var uniq = require('array-uniq');
 
 /** @const {object} gcloud-node's package.json file. */
 var PKG = require('../../package.json');
@@ -81,13 +82,13 @@ var ApiError = createErrorClass('ApiError', function(errorBody) {
 
   if (errorBody.errors && errorBody.errors.length === 1) {
     messages.push(errorBody.errors[0].message);
-  } else if (errorBody.response.body) {
+  } else if (errorBody.response && errorBody.response.body) {
     messages.push(errorBody.response.body.toString());
   } else if (!errorBody.message) {
     messages.push('Error during request.');
   }
 
-  this.message = messages.join(' - ');
+  this.message = uniq(messages).join(' - ');
 });
 
 /**

package.json

@@ -83,6 +83,7 @@
   ],
   "dependencies": {
     "JSONStream": "^1.0.7",
+    "array-uniq": "^1.0.2",
     "arrify": "^1.0.0",
     "async": "^1.4.2",
     "concat-stream": "^1.5.0",

test/common/util.js

@@ -203,6 +203,22 @@ describe('common/util', function() {
 
       assert.strictEqual(apiError.message, expectedErrorMessage);
     });
+
+    it('should filter out duplicate errors', function() {
+      var expectedErrorMessage = 'Error during request.';
+
+      var error = {
+        code: 100,
+        message: expectedErrorMessage,
+        response: {
+          body: expectedErrorMessage
+        }
+      };
+
+      var apiError = new util.ApiError(error);
+
+      assert.strictEqual(apiError.message, expectedErrorMessage);
+    });
   });
 
   describe('extendGlobalConfig', function() {