#34 Why did build fail with "<dir> not found" error?

[Doug Bunting]

One of two things are likely wrong:
- you are running a build target that requires some
other target to have been run; for example,
rm -rf build
ant print.classpath -Dclasspath=tomcat.compile.classpath
will fail because the 'clean' target has not yet been
run. Run that target and everything should work.
- you have changed the build scripts to be more
fragile. More below on this possibility.

Ant does not evaluate paths until they are used. This
evaluation (say, within <pathconvert/> may fail if the
directory mentioned in the referenced path does not exist.

Some examples:
- <fileset dir="/dev/null" ... /> aborts the script
- <fileset dir="<does.not.exist> ... /> aborts the script
- <fileset file="<dir.that.does.not.exist>/..."/>
aborts the script
- <fileset dir=""
includes="<existing.dir>/<existing.file>"/> results in an
empty set, as does dir="/"
- <fileset dir=""
includes="<dir.that.does.not.exist>/<file.that.does.not.exist>"/>
also results in an empty set, fortunately it does so
quietly.

The work-around is to ensure what goes into the dir
attribute is an existing directory.