marshalBigInt return 8 bytes slice in all cases except for big.Int, which returns a variable length slice

[fesiqueira]

What version of Cassandra are you using?

3.11.11

What version of Gocql are you using?

v1.6.0

What version of Go are you using?

1.21.6

What did you do?

Marshaled a big.Int variable. A example can be found here: https://go.dev/play/p/xShpJBbX2f2

What did you expect to see?

I expected the query to work

What did you see instead?

A Cassandra error message: Expected 8 or 0 byte long (7).

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What happens is that when Marshaling to bigint, for all other types the marshalBigInt internal function will return a slice with length 8, but for big.Int it returns a variable length slice, which can sometimes be 7, 14, ..., depending of the underlying value of the big.Int.

I'd like to know if it's known and if it's a bug. Per math/big documentation, to get a fixed length slice the big.Int.FillBytes should be used instead.