pagination sample code creates an infinite loop when the list contains a number of items divisible by pageSize

[dvmorris]

Environment details

• OS type and version: Linux, CentOS 7
• Python version: 3.8.10
• pip version: 20.2.3
• google-api-python-client version: 2.49.0

Steps to reproduce

1. Follow the sample pagination code here: https://googleapis.github.io/google-api-python-client/docs/pagination.html
2. Implement this technique for the users list API, against a Cloud Identity environment that has 100, 200, 300, or 400 users (because pageSize defaults to 100... this should theoretically be reproduced with 5 users and a pageSize of 5, etc.)

Code example

    request = service.users().list(domain='*********.com', orderBy='email')
    users = []
    while request is not None:
        user_list = request.execute()
        for user in user_list['users']:
            users.append(user)
        request = service.users().list_next(request, user_list)

Output

After the first N pages of users returns from the API, the response object contains this (see below), and the code sample produces an infinite loop:

{'etag': '"SEQQBYC70u6XQ2UUjmjNYw6b0a5EzY0mTMShjiZga8A/HMFwD2wLX237BRmKZQUJYB5ZE7U"', 'kind': 'admin#directory#users'}

{'etag': '"SEQQBYC70u6XQ2UUjmjNYw6b0a5EzY0mTMShjiZga8A/HMFwD2wLX237BRmKZQUJYB5ZE7U"', 'kind': 'admin#directory#users'}

{'etag': '"SEQQBYC70u6XQ2UUjmjNYw6b0a5EzY0mTMShjiZga8A/HMFwD2wLX237BRmKZQUJYB5ZE7U"', 'kind': 'admin#directory#users'}

{'etag': '"SEQQBYC70u6XQ2UUjmjNYw6b0a5EzY0mTMShjiZga8A/HMFwD2wLX237BRmKZQUJYB5ZE7U"', 'kind': 'admin#directory#users'}

...

[dvmorris]

This is the best I could figure out how to address the issue in all cases, no matter how many users are in the list, and no matter what page size (maxResults) you set

service = build('admin', 'directory_v1', credentials=creds)
page_token = None
users = []
while True:
    user_list = service.users().list(domain='*****.com',
                               orderBy='email',
                               maxResults=2,
                               pageToken=page_token).execute()
    users.extend(user_list['users'] if 'users' in user_list else [])
    page_token = user_list.get('nextPageToken', None) if user_list.get('nextPageToken', None) != page_token else None
    if page_token is None:
        break