Apache avro schema resolution throws an error, when deserializing, if the
writer's enum symbol is not present in the reader's enum definition[1]. To
illustrate with example consider the following enum that is shared by the
writer and the reader.
Version1:
protocol SampleProtocol {
enum Suit{
SPADES, HEARTS, CLUBS
}
record Card {
Suit suit;
}
}
Now if the writer adds a new value "DIAMONDS" to the Suit enum and serializes
a datum with the "DIAMONDS"
Version2:
protocol SampleProtocol {
enum Suit{
SPADES, HEARTS, CLUBS, DIAMONDS
}
record Card {
Suit suit;
}
}
Now Reader,when deserializing with version 1 of the schema, will thrown an
error as it does not understand "DIAMONDS". This forces the reader and the
writer enum definitions to be sync.
As this is a non passive change whenever a enum gets updated, I am curios why
this was designed to be non-passive, rather than simply ignoring the new value
or giving a "special" unsupported enum value if the enum is required.
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