xs:date and xs:datetime allow negative integers for the year but the functions fn:year-from-datetime and fn:year-from-date do not process this correctly. With a year of -0001, the functions both return 2 for the year instead of the expected -1.

See tests:
test_xfromdatetime_04
test_xfromdate_03

In files:
daffodil-test/src/test/resources/edu/illinois/ncsa/daffodil/section23/dfdl_functions/Functions.tdml
daffodil-test/src/test/scala-debug/edu/illinois/ncsa/daffodil/section23/dfdl_expressions/TestDFDLExpressionsDebug.scala