[CZT-Devel] IndexOutOfBoundsException in typechecker-z and a solution

[Julian R. <jro...@gm...>]

There is a bug in the CZT typechecker-z software which can result in an
IndexOutOfBoundsException when using the "-d" cmdline option (use before
definition). The error output requests an email be sent to czt-devel.

corejava-z\target\generated-sources\gnast\net\sourceforge\czt\z\impl\ZParaListImpl.java:246
throws-up an ArrayIndexOutOfBoundsException, the cause of which is
code\typechecker\typechecker-z\src\main\java\net\sourceforge\czt\typecheck\z\Checker.java:881
in the function reorderParaList (dependancy graph paragraph reordering).

Please find attached a solution in Checker.java:reorderParaList, summarised
in the attached file diff-checker-java, which guards against the index out
of bounds from happening. (The four other CZT implementations of
Checker.java (circus, circusconf, zeves, oz) do not include a
reorderParaList function.)

Please see proof of fix attached, which shows test output from the before
and after change to both ZWT (ZWordTools) and CZT jar files with and
without "-d" cmdline option. The minimal zed8 input test file is also
attached. My builds are made using JDK11 and Maven 3.8.1.

With thanks,
julian