Hi,

I have a custom Ivy resolver that keeps a static cache because it is 
time-consuming to initialise.

However, this cache doesn't work in a multi-project build, because the 
ivysettings/classpath command is creating a new URLClassLoader for each 
subant iteration, so all static class fields are reset.

<ivysettings>

  <classpath file="${ivy.settings.dir}/sigil-ivy-plugin.jar" />

  <typedef name="sigil" classname="org.cauldron.bld.ivy.SigilResolver" />

  ...

</ivysettings>


I'm building multiple projects, using ivy:buildlist and subant, as in 
the Ivy multi-project example.

Each iteration of subant, causes IvySettings to reload.
IvySettings.classloader is thus null and so a new URLClassLoader is created.

I temporarily worked around this by loading my plugin at the same time 
as Ivy (i.e. not using settings/classpath), but I'd really like the 
setting/classpath method to work too.

One possible solution would be to add a "loaderRef" attribute to 
settings/classpath, similar to the Ant taskdef/typedef tasks, to make it 
use the same ClassLoader.

Alternatively, IvySettings could simply be changed to only create a new 
URLClassLoader if the list of URLs  has changed. I attach a simple patch 
to IvySettings.java that does this and seems to work OK.

If this is valid and useful, let me know and I'll raise it in Jira.

Thanks,

Derek