Why does Flink copy code from Spark?

Posted by Edward Lee on Dec 27, 2015; 7:51am
URL: http://deprecated-apache-flink-mailing-list-archive.368.s1.nabble.com/Why-does-Flink-copy-code-from-Spark-tp9666.html

Lately I have been studying the source code to understand the internals.
One thing that really surprised me was that a lot of code throughout Flink
was very similar to Spark.

Open source projects learn from each other and apply similar ideas.
However, I am not talking about applying similar ideas. I am talking about
literal copy of code. Many files seemed like they were created by
copy-pasting code directly from Spark and then renaming the variable names
to avoid looking identical.

As I study more, I find "copy-pasted" code throughout Flink, from actors to
machine learning to analyzer to code generation. A few files have
attribution, but most of them do not.

I thought Flink was more advanced. Why?