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https://issues.apache.org/jira/browse/ZOOKEEPER-2320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15345506#comment-15345506
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Michael Han commented on ZOOKEEPER-2320:
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bq. In addition, the zk_hashtable.h file has been moved to the include
directory so that we can check for local watches in the tests.
Not sure if we should do this, or simply replicate the 'pathHasWatcher' logic
in test code. My concern moving this header in include directory exposes the
header to end users as well, so we will have the obligation to support this
file moving forward (less flexibility to change the file as backwards
compatibility should be considered as well.).
> C-client crashes when removing watcher asynchronously in "local" mode
> ---------------------------------------------------------------------
>
> Key: ZOOKEEPER-2320
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2320
> Project: ZooKeeper
> Issue Type: Bug
> Components: c client
> Affects Versions: 3.5.1
> Reporter: Hadriel Kaplan
> Assignee: Abraham Fine
> Attachments: ZOOKEEPER-2320.patch
>
>
> The C-client library will crash when invoking the asynchronous
> {{zoo_aremove_watchers()}} API function with the '{{local}}' argument set to
> 1.
> The reason is: if the local argument is 1/true, then the code does
> '{{notify_sync_completion((struct sync_completion *)data);}}' But casting the
> '{{data}}' variable to a {{sync_completion}} struct pointer is bogus/invalid,
> and when it's later handles as that struct pointer it's accessing invalid
> memory.
> As a side note: it will work ok when called _synchronously_ through
> {{zoo_remove_watchers()}}, because that function creates a
> {{sync_completion}} struct and passes it to the asynch
> {{zoo_aremove_watchers()}}, but it will not work ok when the asynch function
> is used directly for the reason stated perviously.
> Another side note: the docs state that setting the 'local' flag makes the
> C-client remove the watcher "even if there is no server connection" - but
> really it makes the C-client remove the watcher without notifying the server
> at *all*, even if the connection to a server is up. (well... that's what it
> would do if it didn't just crash instead ;)
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