[tamnd]

Summary

This adds the operators of the multirange types, as multirangetypes.c has them. Each operator takes a multirange on one side and a multirange, a range or a value on the other side.

Changes

• multirange_union (+), multirange_minus (-) and multirange_intersect (*). The difference and the intersection go through the two multiranges in one pass, as multirange_minus_internal and multirange_intersect_internal do.
• The set function multirange_minus_multi, which gives no row for an empty difference.
• &&, @> and <@ with a multirange or a range on each side, and @> and <@ with a value. Each side is a list of ranges in order, so one pass finds the answer.
• <<, >>, &<, &> and -|-. These compare only the lower bound of the first range and the upper bound of the last range, so {[1,5),[7,8)} -|- {[5,7)} is false, as in PostgreSQL.
• range_split_internal in the range module gives the two parts of a range that another range cuts.

Tests

• The session test multirange_ops is the output of PostgreSQL 19 for the same script in a new database. It has each operator with empty, infinite and discrete multiranges, the errors of the types that do not match, a cross join of multiranges and a query with parameters.
• A unit test for the difference, the intersection, the overlap and the containment.
• fmt, clippy, the workspace tests and the checks of xtask pass on server1.