Next, I have reviewed patches
v17-0010-Track-sort-direction-in-SortGroupClause.patch
v17-0011-Track-scan-reversals-in-MergeJoin.patch
Both of these seem ok and sensible to me.
They take the concept of the "reverse" flag that already exists in the
affected code and just apply it more consistently throughout the various
code layers, instead of relying on strategy numbers as intermediate
storage. This is both helpful for your ultimate goal in this patch
series, and it also makes the affected code areas simpler and more
consistent and robust.