fix(query): does not include primary key when grouping (#8162)

* fix(query): does not include primary key when grouping

When grouping a model that links through a belongsTo association the primaryKey is no longer automatically added to the attributes list.

* test(query): uses stricter type checks for primary key group tests

lib/model.js

@@ -1514,9 +1514,11 @@ class Model {
         this._validateIncludedElements(options, tableNames);
         this._validateIncludedElements(options, tableNames);
 
 
         // If we're not raw, we have to make sure we include the primary key for deduplication
         // If we're not raw, we have to make sure we include the primary key for deduplication
-        if (options.attributes && !options.raw && this.primaryKeyAttribute &&  options.attributes.indexOf(this.primaryKeyAttribute) === -1) {
+        if (options.attributes && !options.raw && this.primaryKeyAttribute && options.attributes.indexOf(this.primaryKeyAttribute) === -1) {
           options.originalAttributes = options.attributes;
           options.originalAttributes = options.attributes;
-          options.attributes = [this.primaryKeyAttribute].concat(options.attributes);
+          if (!options.group || !options.hasSingleAssociation || options.hasMultiAssociation) {
+            options.attributes = [this.primaryKeyAttribute].concat(options.attributes);
+          }
         }
         }
       }
       }
 
 

test/integration/model/findAll/group.test.js

@@ -51,6 +51,49 @@ describe(Support.getTestDialectTeaser('Model'), () => {
           expect(parseInt(posts[1].get('comment_count'))).to.be.equal(2);
           expect(parseInt(posts[1].get('comment_count'))).to.be.equal(2);
         });
         });
       });
       });
+
+      it('should not add primary key when grouping using a belongsTo association', () => {
+        const Post = current.define('Post', {
+          id: { type: DataTypes.INTEGER, autoIncrement: true, primaryKey: true },
+          name: { type: DataTypes.STRING, allowNull: false }
+        });
+
+        const Comment = current.define('Comment', {
+          id: { type: DataTypes.INTEGER, autoIncrement: true, primaryKey: true },
+          text: { type: DataTypes.STRING, allowNull: false }
+        });
+
+        Post.hasMany(Comment);
+        Comment.belongsTo(Post);
+
+        return current.sync({ force: true }).then(() => {
+          return Post.bulkCreate([
+            { name: 'post-1' },
+            { name: 'post-2' }
+          ]);
+        }).then(() => {
+          return Comment.bulkCreate([
+            { text: 'Market', PostId: 1 },
+            { text: 'Text', PostId: 2 },
+            { text: 'Abc', PostId: 2 },
+            { text: 'Semaphor', PostId: 1 },
+            { text: 'Text', PostId: 1 }
+          ]);
+        }).then(() => {
+          return Comment.findAll({
+            attributes: ['PostId', [Sequelize.fn('COUNT', Sequelize.col('Comment.id')), 'comment_count']],
+            include: [
+              { model: Post, attributes: [] }
+            ],
+            group: ['PostId']
+          });
+        }).then(posts => {
+          expect(posts[0].get().hasOwnProperty('id')).to.equal(false);
+          expect(posts[1].get().hasOwnProperty('id')).to.equal(false);
+          expect(parseInt(posts[0].get('comment_count'))).to.be.equal(3);
+          expect(parseInt(posts[1].get('comment_count'))).to.be.equal(2);
+        });
+      });
     });
     });
   });
   });
 });
 });