[GitHub] beam pull request #4024: [BEAM-2304] Fixed bug allowing declared state to be...

[luke-zhu <gi...@git.apache.org>]

GitHub user luke-zhu opened a pull request:

    https://github.com/apache/beam/pull/4024

    [BEAM-2304] Fixed bug allowing declared state to be accessed as a superclass.

    Follow this checklist to help us incorporate your contribution quickly and easily:
    
     - [x] Make sure there is a [JIRA issue](https://issues.apache.org/jira/projects/BEAM/issues/) filed for the change (usually before you start working on it).  Trivial changes like typos do not require a JIRA issue.  Your pull request should address just this issue, without pulling in other changes.
     - [x] Each commit in the pull request should have a meaningful subject line and body.
     - [x] Format the pull request title like `[BEAM-XXX] Fixes bug in ApproximateQuantiles`, where you replace `BEAM-XXX` with the appropriate JIRA issue.
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    ---
    This is a fix to BEAM-2304: State declared with one class cannot be accessed as a superclass (applies to BagState|CombiningState <: GroupingState).
    
    I changed the stateId check in `analyzeExtraParameter` of `DoFnSignatures.java` to check that the initial state declaration is a subtype of the state type of `processElement` instead of equal to.
    
    I updated the corresponding error message and added a test to `DoFnSignaturesTest.java` which makes sure that the example code in the original JIRA issue instantiates a DoFn without a runtime error.
    
    This is my first pull request. I'm excited to learn from everyone!


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/luke-zhu/beam luke

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/beam/pull/4024.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 #4024
    
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commit ed29adf3de87a8f118316a9e6fb4cf398da135ca
Author: luke-zhu <lu...@brown.edu>
Date:   2017-10-21T05:06:00Z

    Allowed for declared state to be accessed as a supertype and updated error messages.

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