Status: IN
Type promotion during schema resolution is strictly one-directional (int→long→float→double, int→float, int→double, long→double); reverse promotion (e.g., long→int) is not supported and raises SchemaCompatibilityError.
Source: entries/2026/05/29/avro-serializer-avro_serializer.md
PROMOTIONS = {
("int", "long"), ("int", "float"), ("int", "double"),
("long", "float"), ("long", "double"),
("float", "double"),
} # int->long ok, long->int is SchemaCompatibilityError