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https://issues.apache.org/jira/browse/HADOOP-9912?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13772002#comment-13772002
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Jason Lowe commented on HADOOP-9912:
------------------------------------
Thanks [~eli] for the excellent writeup and thanks [~cmccabe] for proposing a
design of new APIs.
Regarding the issue of what to do with the existing APIs, I had an offline
discussion with [~daryn], [~kihwal], and [~nroberts]. At this point we think
the best choice for the existing listStatus API is to follow symlinks when it
can but throw an exception when it cannot. It's a conservative approach where
we're basically saying we have no idea how the caller will react if it sees the
raw symlink since it never exposed one in previous versions. Therefore we
aren't assuming it will end well if we start exposing symlinks in the results
and change the previously-assumed semantics of isDir() on those results.
Yes, this does mean that "bad" symlinks (dangling, pointing within a protected
directory tree, referencing another filesystem that is currently unavailable)
could cause programs to blow up when they encounter them in a directory.
However we think that is preferable to the possible alternative of silently
missing data because the app misinterpreted the raw symlink and skipped it when
it should have caused an error. Ideally the existing globStatus API would use
a symlink-aware listStatus API internally so it could avoid erroring-out on
symlinks that would be filtered out by the specified pattern/filter.
> globStatus of a symlink to a directory does not report symlink as a directory
> -----------------------------------------------------------------------------
>
> Key: HADOOP-9912
> URL: https://issues.apache.org/jira/browse/HADOOP-9912
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 2.1.0-beta
> Reporter: Jason Lowe
> Priority: Blocker
> Attachments: HADOOP-9912-testcase.patch, new-hdfs.txt, new-local.txt,
> old-hdfs.txt, old-local.txt
>
>
> globStatus for a path that is a symlink to a directory used to report the
> resulting FileStatus as a directory but recently this has changed.
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