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https://issues.apache.org/jira/browse/HTTPCORE-638?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Malay Shah updated HTTPCORE-638:
--------------------------------
    Description: 
Using `SharedOutputBuffer` in conjunction with `ContentOutputStream` can cause 
`endStream` to be called multiple times on the `DataStreamChannel`. I've 
noticed this happening in my code where I'm using something nearly identical 
`AbstractClassicEntityProducer` (only difference is that I use my own thread to 
produce the data). When this happens, the `HttpAsyncMainClientExec`'s 
`messageCountDown` goes to zero and the exchange is considered completed but 
since no response was processed, it results in a `cancel` callback. I should 
note that this does not happen all the time but frequently enough when I'm 
calling into a local web server.

Here's how `endStream` ends up being called twice:
 * Once from the producer thread when it calls close on the 
`ContentOutputStream`
 * one from the call to `SharedOutputBuffer.flush` from 
`OutputStreamClassicEntityProducer.produce`.

>From my understanding, this sequence is legitimate as 
>`OutputStreamClassicEntityProducer.produce` is called repeatedly, and it can 
>hold on to the DataStreamChannel to call into asynchronously (from the comment 
>in `AsyncDataProducer`). When I've seen this happen, both calls to `endStream` 
>happen with one or two milliseconds of each other.

There is no guard in SharedOutputBuffer to ensure that `endStream` is called 
only once. Is this the correct fix? I'm happy to submit a PR if this the right 
solution.

Thank you!

  was:
Using `SharedOutputBuffer` in conjunction with `ContentOutputStream` can cause 
`endStream` to be called multiple times on the `DataStreamChannel`. I've 
noticed this happening in my code where I'm using something nearly identical 
`AbstractClassicEntityProducer` (only difference is that I use my own thread to 
produce the data. When this happens, the `HttpAsyncMainClientExec`'s 
`messageCountDown` goes to zero and the exchange is considered completed but 
since no response was processed, it results in a `cancel` callback. I should 
note that this does not happen all the time but frequently enough when I'm 
calling into a local web server.

Here's how `endStream` ends up being called twice:
* Once from the producer thread when it calls close on the `ContentOutputStream`
* one from the call to `SharedOutputBuffer.flush` from 
`OutputStreamClassicEntityProducer.produce`.

>From my understanding, this sequence is legitimate as 
>`OutputStreamClassicEntityProducer.produce` is called repeatedly, and it can 
>hold on to the DataStreamChannel to call into asynchronously (from the comment 
>in `AsyncDataProducer`. When I've seen this happen, both calls to `endStream` 
>happen with one or two milliseconds of each other.

There is no guard in SharedOutputBuffer to ensure that `endStream` is called 
only once. Is this the correct fix? I'm happy to submit a PR if this the right 
solution.

Thank you!


> SharedOutputBuffer calls endStream multiple times
> -------------------------------------------------
>
>                 Key: HTTPCORE-638
>                 URL: https://issues.apache.org/jira/browse/HTTPCORE-638
>             Project: HttpComponents HttpCore
>          Issue Type: Bug
>          Components: HttpCore NIO
>    Affects Versions: 5.0
>            Reporter: Malay Shah
>            Priority: Major
>
> Using `SharedOutputBuffer` in conjunction with `ContentOutputStream` can 
> cause `endStream` to be called multiple times on the `DataStreamChannel`. 
> I've noticed this happening in my code where I'm using something nearly 
> identical `AbstractClassicEntityProducer` (only difference is that I use my 
> own thread to produce the data). When this happens, the 
> `HttpAsyncMainClientExec`'s `messageCountDown` goes to zero and the exchange 
> is considered completed but since no response was processed, it results in a 
> `cancel` callback. I should note that this does not happen all the time but 
> frequently enough when I'm calling into a local web server.
> Here's how `endStream` ends up being called twice:
>  * Once from the producer thread when it calls close on the 
> `ContentOutputStream`
>  * one from the call to `SharedOutputBuffer.flush` from 
> `OutputStreamClassicEntityProducer.produce`.
> From my understanding, this sequence is legitimate as 
> `OutputStreamClassicEntityProducer.produce` is called repeatedly, and it can 
> hold on to the DataStreamChannel to call into asynchronously (from the 
> comment in `AsyncDataProducer`). When I've seen this happen, both calls to 
> `endStream` happen with one or two milliseconds of each other.
> There is no guard in SharedOutputBuffer to ensure that `endStream` is called 
> only once. Is this the correct fix? I'm happy to submit a PR if this the 
> right solution.
> Thank you!



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