Hi everyone, I would like to propose to drop Python 2 support(Currently Python 2.7, 3.5, 3.6, 3.7 are all supported in Flink) as it's coming to an end at Jan 1, 2020 [1]. A lot of projects [2][3][4] has already stated or are planning to drop Python 2 support.
The benefits of dropping Python 2 support are: 1. Maintaining Python 2/3 compatibility is a burden and it makes the code complicate as Python 2 and Python 3 is not compatible. 2. There are many features which are only available in Python 3.x such as Type Hints[5]. We can only make use of this kind of features after dropping the Python 2 support. 3. Flink-python depends on third-part projects, such as Apache Beam (may add more dependencies such as pandas, etc in the near future), it's not possible to upgrade them to the latest version once they drop the Python 2 support. Here are the options we have: 1. Drop Python 2 support in 1.10: As flink-python module is a new module added since 1.9.0 and so dropping Python 2 support at the early stage seems a good choice for us. 2. Deprecate Python 2 in 1.10 and drop its support in 1.11: As 1.10 is planned to be released around the beginning of 2020. This is also aligned with the official Python 2 support. Personally I prefer option 1 as flink-python is new module and there is no much history reasons to consider. Looking forward to your feedback! Regards, Dian [1] https://pythonclock.org/ <https://pythonclock.org/> [2] https://python3statement.org/ <https://python3statement.org/> [3] https://spark.apache.org/news/plan-for-dropping-python-2-support.html <https://spark.apache.org/news/plan-for-dropping-python-2-support.html> [4] https://lists.apache.org/thread.html/eba6caa58ea79a7ecbc8560d1c680a366b44c531d96ce5c699d41535@%3Cdev.beam.apache.org%3E <https://lists.apache.org/thread.html/eba6caa58ea79a7ecbc8560d1c680a366b44c531d96ce5c699d41535@%3Cdev.beam.apache.org%3E> [5] https://stackoverflow.com/questions/32557920/what-are-type-hints-in-python-3-5 <https://stackoverflow.com/questions/32557920/what-are-type-hints-in-python-3-5>
