Ensure relationships can have multiple errors

Previously we would clobber pre-existing errors, so only the latest
error in the array would show. Now we correctly show everything.

Author: Lee Richmond

src/util/validation-errors.ts

@@ -55,8 +55,18 @@ export default class ValidationErrors {
     } else {
       let relatedAccumulator = {}
       this._processResource(relatedAccumulator, meta);
-      relatedObject.errors = relatedAccumulator
-    }
 
+      // make sure to assign a new error object, instead of mutating
+      // the existing one, otherwise js frameworks with object tracking
+      // won't be able to keep up. Validate vue.js when changing this code:
+      let newErrs = {}
+      Object.keys(relatedObject.errors).forEach((key) => {
+        newErrs[key] = relatedObject.errors[key]
+      });
+      Object.keys(relatedAccumulator).forEach((key) => {
+        newErrs[key] = relatedAccumulator[key]
+      });
+      relatedObject.errors = newErrs
+    }
   }
 }

test/integration/validations-test.ts

@@ -59,6 +59,26 @@ const resetMocks = function() {
                 }
               }
             }
+          },
+          {
+            code: 'unprocessable_entity',
+            status: '422',
+            title: 'Validation Error',
+            detail: 'base some error',
+            meta: {
+              relationship: {
+                name: 'books',
+                type: 'books',
+                ['temp-id']: 'abc1',
+                relationship: {
+                  name: 'genre',
+                  type: 'genres',
+                  id: '1',
+                  attribute: 'base',
+                  message: 'some error'
+                }
+              }
+            }
           }
         ]
       }
@@ -176,8 +196,11 @@ describe('validations', function() {
     instance.save({ with: { books: 'genre' }}).then((success) => {
       expect(instance.isPersisted()).to.eq(false);
       expect(success).to.eq(false);
+
+      // note we're validating multiple properties
       expect(instance.books[0].genre.errors).to.deep.equal({
         name: 'cannot be blank',
+        base: 'some error'
       });
       done();
     });