GitHub user BryanCutler opened a pull request:
https://github.com/apache/spark/pull/16782
[SPARK-19348][PYTHON][WIP] PySpark keyword_only decorator is not thread-safe
## What changes were proposed in this pull request?
The `@keyword_only` decorator in PySpark is not thread-safe. It writes
kwargs to a static class variable in the decorator, which is then retrieved
later in the class method as `_input_kwargs`. If multiple threads are
constructing the same class with different kwargs, it becomes a race condition
to read from the static class variable before it's overwritten. See
[SPARK-19348](https://issues.apache.org/jira/browse/SPARK-19348) for
reproduction code.
This change will write the kwargs to a member variable so that multiple
threads can operate on separate instances without the race condition. It does
not protect against multiple threads operating on a single instance, but that
is better left to the user to synchronize.
## How was this patch tested?
WIP
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/BryanCutler/spark
pyspark-keyword_only-threadsafe-SPARK-19348
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/16782.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #16782
----
commit a15e9b0a78d86685d6b27ac4fdfa37161376b288
Author: Bryan Cutler <[email protected]>
Date: 2017-02-02T23:01:45Z
made a thread-safe addition to keyword_only decorator
commit 83bcce0c2fc33184579224fca18066dbf6891d26
Author: Bryan Cutler <[email protected]>
Date: 2017-02-02T23:11:32Z
remove blank line
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