Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

for v45.

+ foreach_ptr(CookedConstraint, ccon, cookedConstraints)
+ {
+ if (!ccon->skip_validation && ccon->contype == CONSTR_CHECK)
+ {
+ Bitmapset  *attnums = NULL;
+
+ pull_varattnos((Node *) ccon->expr, 1, &attnums);
+
+ /*
+ * Add check only if it contains tableoid
+ * (TableOidAttributeNumber).
+ */
+ if (bms_is_member(TableOidAttributeNumber -
FirstLowInvalidHeapAttributeNumber,
+  attnums))
+ {
+ NewConstraint *newcon;
+
+ newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
+ newcon->name = ccon->name;
+ newcon->contype = ccon->contype;
+ newcon->qual = ccon->expr;
+
+ tab->constraints = lappend(tab->constraints, newcon);
+ }
+ }
+ }

we need to expand the virtual generated column here,
otherwise, bms_is_member would  be not correct.
consider case like:

CREATE TABLE pp (f1 INT, f2 INT generated always as (f1 +
tableoid::int)) PARTITION BY RANGE (f1);
CREATE TABLE pp_1 (f2 INT generated always as (f1 + tableoid::int), f1 int);
ALTER TABLE pp ATTACH PARTITION pp_1 FOR VALUES FROM (-1) TO (10);
CREATE TABLE pp_2 (f2 INT generated always as (f1 + tableoid::int), f1 int);
ALTER TABLE pp ATTACH PARTITION pp_2 FOR VALUES FROM (10) TO (20);
ALTER TABLE PP add check (f2 > 0);

ALTER TABLE pp MERGE PARTITIONS (pp_1, pp_2) INTO pp_12;

In this context, the merge partition command  needs to evaluate the constraint
"pp_f2_check" again on pp_12.

attach minor diff fix this problem.