1. create a job jollychang_test2
2. set Source Code Management as mercurial and Repository URL http://hg.test.com/testA/,build it; set Poll SCM check every minute
3. change Repository URL to http://hg.test.com/testB/

Check the Mercurial Polling Log
it still comparing with the old Repository URL:testA
cat scm-polling.log

Started on Nov 23, 2011 11:16:42 AM
[workspace] $ hg incoming --style /home/jenkins/jobs/jollychang_test2/workspace/tmp1030248719773562341style --no-merges --rev default --newest-first
comparing with http://hg.test.com/testA/
searching for changes
no changes found
Done. Took 19 sec
No changes

cat workspace/.hg/hgrc

[paths]
default = http://hg.test.com/testA/

cat config.xml

<?xml version='1.0' encoding='UTF-8'?>
<project>
<actions/>
<description></description>
<keepDependencies>false</keepDependencies>
<properties/>
<scm class="hudson.plugins.mercurial.MercurialSCM">
<source>http://hg.test.com/testB/</source>
<modules></modules>
<clean>false</clean>
<forest>false</forest>
<browser class="hudson.plugins.mercurial.browser.HgWeb">
<url>http://hg.test.com/testB/</url>
</browser>
</scm>
<canRoam>true</canRoam>
<disabled>false</disabled>
<blockBuildWhenDownstreamBuilding>false</blockBuildWhenDownstreamBuilding>
<blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
<triggers class="vector">
<hudson.triggers.SCMTrigger>
<spec>* * * * *
</spec>
</hudson.triggers.SCMTrigger>
</triggers>
<concurrentBuild>false</concurrentBuild>
<builders>
<hudson.tasks.Shell>
<command>TT=${WORKSPACE}
echo ${SVN_REVISION}</command>
</hudson.tasks.Shell>
</builders>
<publishers/>
<buildWrappers/>