[
https://issues.apache.org/jira/browse/HDFS-7031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14126530#comment-14126530
]
Ryan Blue commented on HDFS-7031:
---------------------------------
My application doesn't know what the incoming Path will look like, so it uses
{{makeQualified}} to fill in the details that may be missing. If there is no
scheme/authority, then those should be taken from the default URI (/some/path
=> hdfs://nn:8020/some/path). If there is only a relative path, then that's
filled in from the working directory Path (path => hdfs://nn:8020/path).
Because the URI argument is a "default", I think that behavior #1 is implied
when the schemes don't match, which fits with my interpretation of the other
examples: qualifying a URI doesn't change what the URI already contains, but
fills in what's missing from it being fully qualified. Behavior #2 would change
the original URI's meaning, not just fill in defaults. That said, I've added a
work-around that only passes in the default FS URI if the schemes don't match
so my application is no longer affected.
I think your argument that {{FileSystem#makeQualified}} is a better fit for
behavior #2 is reasonable, but I don't think there is a reason to change the
current behavior, which throws an IllegalArgumentException that the FS is
incorrect. That's why I'm using {{Path#makeQualified}}, because it seems to
have the behavior I want, to default the values if not specified, in most cases.
> Path#makeQualified copies authority when scheme does not match
> --------------------------------------------------------------
>
> Key: HDFS-7031
> URL: https://issues.apache.org/jira/browse/HDFS-7031
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs-client
> Affects Versions: 2.3.0
> Reporter: Ryan Blue
>
> I have an application that calls {{makeQualified}} that amounts to this:
> {code:java}
> new Path("file:/some/local/path").makeQualified(
> URI.create("hdfs://nn:8020"), new Path("/"));
> {code}
> This unexpectedly produces {{file://nn:8020/some/local/path}}, using the
> authority section from the default URI even though the path that is being
> qualified doesn't have a scheme that matches the default URI.
> In {{Path}}, there is a check to see if the default URI should be used:
> {code:java}
> if (scheme != null &&
> (authority != null || defaultUri.getAuthority() == null))
> return path;
> {code}
> I think this should be:
> {code:java}
> // if the scheme matches and there is no authority, use the default
> if (scheme != null && scheme.equals(defaultUri.getScheme()) &&
> (authority != null || defaultUri.getAuthority() == null))
> return path;
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
