2.2.1

• motoko (moc)

  • bugfix: the upgrade check of enhanced orthogonal persistence now rejects
    changing a record field between var f : [T] and f : [var T], Char
    to or from Nat32, and () to or from Null (or to ?T). It used to
    accept these upgrades, after which the new code misread the old heap. The
    first upgrade from moc 2.2.0 or earlier still accepts them, as the
    stable type those releases stored doesn't tell them apart. Before that
    upgrade, run moc --stable-compatible, which rejects them: for example,
    a stored Nat32 read as a Char can become an invalid code point (a
    surrogate or one above 0x10FFFF), and a var [T] field read as
    [var T] reads the heap out of bounds. Once upgraded, a canister whose
    stable type contains [var T], Char, or () (including tags without
    payload, such as #on) fails to downgrade to moc 2.2.0 or earlier with
    Memory-incompatible program upgrade (#6452).