GitHub user Ethanlm opened a pull request:
https://github.com/apache/storm/pull/2355
[STORM-2769] Fast-fail if output streamId is null
JIRA: https://issues.apache.org/jira/browse/STORM-2769
If streamId is null, we should throw an exception because thrift doesn't
support null in map keys.
A test:

You can merge this pull request into a Git repository by running:
$ git pull https://github.com/Ethanlm/storm STORM-2769
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/storm/pull/2355.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 #2355
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commit ec85f643c5ace9bc1f454f2c33689b97af357e4a
Author: Ethan Li <[email protected]>
Date: 2017-10-03T18:54:18Z
[STORM-2769] Fast-fail if output streamId is null
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