Review feedback on the merged fix:
- derived_nobs was assigned twice, the first one dead - the coalesced form below
is the live value. Removed, so there is one assignment to read.
- making the catalog test a plain %if after the derived-variables test let the
catalog branch override it; the derived view won before and still should. The
catalog branch now requires derived_nobs=0, so the view keeps precedence and
only a catalog with no derived configuration is blanked.
Two guarded if blocks, not %else %if: that construct is what the parser rejected
in this file before ('Expected DO not found'), and the first attempt at this
review point reproduced it - validatefilter and viewdata both failed to complete
again until it was replaced.
Verified: sasjs test -t new -> 64/64 (100%), TEST=0.