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https://issues.apache.org/jira/browse/HADOOP-10663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14029620#comment-14029620
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Chris Nauroth commented on HADOOP-10663:
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I'm not in favor of committing this patch.  This is a continuation of comments 
that I left on MAPREDUCE-5912 here:

https://issues.apache.org/jira/browse/MAPREDUCE-5912?focusedCommentId=14029597&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14029597

The issue raised in MAPREDUCE-5912 is that a change was made that started 
looking for map outputs on the default file system instead of the local file 
system.  This causes problems on Windows if HDFS is the default file system, 
because the path will have a colon due to the drive specifier, and a colon 
isn't a valid character in an HDFS file name.  As I said in my MAPREDUCE-5912 
comment, I don't think that change was correct, even if it appears to be 
working in non-Windows environments.

For the patch here, imagine a situation where the default file system is 
neither the local file system nor HDFS, and that file system implementation 
does allow colons in file names.  With this patch, a {{Path}} with no scheme 
and a path that "looks like" a Windows path with a drive spec can get misrouted 
to local file system instead of the default file system.  I admit this is 
somewhat contrived, but it sure would create confusion if anyone ran into it.

I'd like to resolve this as won't fix.  [~rusanu] and [~chris.douglas], does 
this sound OK?

> Path.getFileSystem should identify Windows drive (c:) like files and return 
> the localFS
> ---------------------------------------------------------------------------------------
>
>                 Key: HADOOP-10663
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10663
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 3.0.0
>            Reporter: Remus Rusanu
>            Assignee: Remus Rusanu
>         Attachments: HADOOP-10663.1.patch
>
>
> While investigating the problem with MAPREDUCE-5912 I considered that the 
> fact that asking a Windows specific Path to get its file system should not 
> return the default FS, but the localFS. Specifically, I believe that 
> Path.initialize should identify such names as belonging to the 'file://' 
> scheme (when null) and so create appropriate URIs.
> I do not have the know-how to evaluate the bigger impact of such a change.



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