The new logic checks for any type of nil at the beginning of Encode and
then either treats it as NULL or calls the driver.Valuer method if
appropriate.
This should preserve the existing nil normalization while restoring the
ability to encode nil driver.Valuer values.
pgx v5 introduced nil normalization for typed nils. This means that
[]byte(nil) is normalized to nil at the edge of the encoding system.
This simplified encoding logic as nil could be encoded as NULL and type
specific handling was unneeded.
However, database/sql compatibility requires Value to be called on a
nil pointer that implements driver.Valuer. This was broken by
normalizing to nil.
This commit changes the normalization logic to not normalize pointers
that directly implement driver.Valuer to nil. It still normalizes
pointers that implement driver.Valuer through implicit derefence.
e.g.
type T struct{}
func (t *T) Value() (driver.Value, error) {
return nil, nil
}
type S struct{}
func (s S) Value() (driver.Value, error) {
return nil, nil
}
(*T)(nil) will not be normalized to nil but (*S)(nil) will be.
https://github.com/jackc/pgx/issues/1566
This improves handling of unregistered types. In general, they should
"just work". But there are performance benefits gained and some edge
cases avoided by registering types. Updated documentation to mention
this.
https://github.com/jackc/pgx/issues/1445
Jack Christensen
mateuszkowalke
Ville Skyttä