[jira] [Commented] (HADOOP-9972) new APIs for listStatus and globStatus to deal with symlinks

["Colin Patrick McCabe (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-9972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13769646#comment-13769646 ] 

Colin Patrick McCabe commented on HADOOP-9972:
----------------------------------------------

I think we can probably let {{FileContext#listStatus}} and {{FileContext#Util#globStatus}} default to *not* fully resolving symlinks.  This makes sense, since {{FileContext}} has had symlink support  for a long time, and doesn't have as much legacy code relying on it.

We also probably need some way of sensibly handling errors in globStatus.  Right now, we really only have the choice of ignoring the error, and throwing an exception which ends the whole globStatus.  We should add some options.
                
> new APIs for listStatus and globStatus to deal with symlinks
> ------------------------------------------------------------
>
>                 Key: HADOOP-9972
>                 URL: https://issues.apache.org/jira/browse/HADOOP-9972
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: fs
>    Affects Versions: 2.1.1-beta
>            Reporter: Colin Patrick McCabe
>            Assignee: Colin Patrick McCabe
>
> Based on the discussion in HADOOP-9912, we need new APIs for FileSystem to deal with symlinks.  The issue is that code has been written which is incompatible with the existence of things which are not files or directories.  For example,
> there is a lot of code out there that looks at FileStatus#isFile, and
> if it returns false, assumes that what it is looking at is a
> directory.  In the case of a symlink, this assumption is incorrect.
> It seems reasonable to make the default behavior of {{FileSystem#listStatus}} and {{FileSystem#globStatus}} be fully resolving symlinks, and ignoring dangling ones.  This will prevent incompatibility with existing MR jobs and other HDFS users.  We should also add new versions of listStatus and globStatus that allow new, symlink-aware code to deal with symlinks as symlinks.

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