The "linecontainsregexp" filter reader does not support a "regexp" attribute. The regular expression should be supplied as a nested "regexp" element. This table should be fixed: https://ant.apache.org/manual/Types/filterchain.html#linecontainsregexp
Thanks, you are correct. Actually this is only half of the story, when you use the syntax of <filterreader classname="org.apache.tools.ant.filters.LineContainsRegExp"> <param type="regexp" value="foo"/> </filterreader> then it works, it is just not exposed as attribute on the <linecontainsregex> element. Rather than documenting the fact, I'll add the attribute to the upcoming releases and add an appropriate since marker to the manual.
fixed with git commit 5347475 for 1.9.10 and 1.10.2