Database#close(): Promise doesn't handle SessionPool#close() properly

[nabeix]

Database#close() has Promise interface.

https://github.com/googleapis/nodejs-spanner/blob/main/src/database.ts#L627

But I found that await database.close() or database.close().then() doesn't wait SessonPool#close() properly.

nodejs-spanner/src/database.ts

Line 634 in f915bd1

this.pool_.close(callback!);

I think this code should be handle callback as followings:

if (typeof callback === 'function') {
  this.pool_.close(callback);
} else {
  return new Promise((resolve, reject) => {
    callback(err => {
      if (err) {
        reject(err);
      }  else {
        resolve();
      }
    });
  });
}

[surbhigarg92]

Hi @nabeix Can you please share an example or repro steps for us to reproduce this issue ?