Details
Minor Description
If I declare a <cachefileset> for a configuration that is present but empty, I get a fileset that (as expected) matches no files.
The problem is that when used, that fileset decides to match no files by recursively scanning all files starting from the current working directory (checked via strace and via a JVM thread dump)
In our case, often the CWD is the top of our build tree, so this takes a very long time to work out that the fileset is in fact empty.
Specifically, we're doing this (inside a macrodef)
<ivy:cachefileset setid="@
{module}.docdeps" conf="doc" type="javadoc.zip"/><unzip dest="${target}/javadoc">
<patternset>
<include name="*/package-list"/>
</patternset>
<fileset refid="@{module}
.docdeps"/>
</unzip>
and the unzip step takes a very, very, long time to do nothing when the "doc" conf is empty.
If I replace the use of cachefileset with an explicit fileset that matches nothing, it runs fast as expected.