fix(mssql): describeTable for VARCHAR(MAX) (#10795)

lib/dialects/mssql/query.js

@@ -176,8 +176,12 @@ class Query extends AbstractQuery {
           result[_result.Name].type.includes('VARCHAR')
           result[_result.Name].type.includes('VARCHAR')
           && _result.Length
           && _result.Length
         ) {
         ) {
+          if (_result.Length === -1) {
+            result[_result.Name].type += '(MAX)';
+          } else {
             result[_result.Name].type += `(${_result.Length})`;
             result[_result.Name].type += `(${_result.Length})`;
           }
           }
+        }
 
 
       }
       }
     }
     }

test/integration/dialects/mssql/regressions.test.js

@@ -82,4 +82,17 @@ if (dialect.match(/^mssql/)) {
         });
         });
     });
     });
   });
   });
+
+  it('sets the varchar(max) length correctly on describeTable', function() {
+    const Users = this.sequelize.define('_Users', {
+      username: Sequelize.STRING('MAX')
+    }, { freezeTableName: true });
+
+    return Users.sync({ force: true }).then(() => {
+      return this.sequelize.getQueryInterface().describeTable('_Users').then(metadata => {
+        const username = metadata.username;
+        expect(username.type).to.include('(MAX)');
+      });
+    });
+  });
 }
 }