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From: Apache Wiki <wikidiffs@apache.org>
To: Apache Wiki <wikidiffs@apache.org>
Date: Fri, 11 Feb 2011 18:01:35 -0000
Message-ID: <20110211180135.92402.34819@eosnew.apache.org>
Subject: 
 =?utf-8?q?=5BHadoop_Wiki=5D_Update_of_=22GitAndHadoop=22_by_SteveLoughran?=

Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for ch=
ange notification.

The "GitAndHadoop" page has been changed by SteveLoughran.
The comment on this change is: details on ivy cache contamination.
http://wiki.apache.org/hadoop/GitAndHadoop?action=3Ddiff&rev1=3D13&rev2=3D14

--------------------------------------------------

  =

  This Ant target not only builds the JAR files, it copies it to the local =
{{{${user.home}/.m2}}} directory, where it will be picked up by the "intern=
al" resolver. You can check that this is taking place by running {{{ant ivy=
-report}}} on a project and seeing where it gets its dependencies.
  =

- '''Warning:''' it's easy for old JAR versions to get cached and picked up=
. You will notice this early if something in hadoop-hdfs or hadoop-mapreduc=
e doesn't compile, but if you are unlucky things do compile, just not work =
as your updates are not picked up. Run {{{ant clean-cache}}} to fix this =

+ '''Warning:''' it's easy for old JAR versions to get cached and picked up=
. You will notice this early if something in hadoop-hdfs or hadoop-mapreduc=
e doesn't compile, but if you are unlucky things do compile, just not work =
as your updates are not picked up. Run {{{ant clean-cache}}} to fix this. =

+ =

+ By default, the trunk of the HDFS and mapreduce projects are set to grab =
the snapshot versions that get built and published into the Apache snapshot=
 repository nightly. While this saves developers in these projects the comp=
lexity of having to build and publish the upstream artifacts themselves, it=
 doesn't work if you do want to make changes to things like hadoop-common. =
You need to make sure the local projects are picking up what's being built =
locally. =

+ =

+ To check this in the hadoop-hdfs project, generate the Ivy dependency rep=
orts using the internal resolver:
+ {{{
+ ant ivy-report -Dresolvers=3Dinternal
+ }}}
+ =

+ Then browse to the report page listed at the bottom of the process, switc=
h to the "common" tab, and look for hadoop-common JAR. It should have a pub=
lication timestamp which contains the date and time of your local build. Fo=
r example, the string "	20110211174419"> means the date 2011-02-11 and the =
time of 17:44:19. If an older version is listed, you probably have it cache=
d in the ivy cache -you can fix this by removing everything from the org.ap=
ache corner of this cache.
+ =

+ {{{
+ rm -rf ~/.ivy2/cache/org.apache.hadoop
+ }}}
+ =

+ Rerun the {{{ivy-report}}} target and check that the publication date is =
current to verify that the version is now up to date.
+ =

  =

  =3D=3D=3D Testing =3D=3D=3D
 =20