message: TFS#875774 - reject call to saveChanges in read-only IModelDb
diff: @@ -397,6 +397,9 @@ export class IModelDb extends IModel {
  * @throws [[IModelError]] if there is a problem saving changes or if there are pending, un-processed lock or code requests.
  */
  public saveChanges(description?: string) {
  + if (this.openMode === OpenMode.Readonly)
  + throw new IModelError(IModelStatus.ReadOnly, "", Logger.logError);
  +
  if (!this.briefcase)
  throw this._newNotOpenError();
  