StructScan doesn't work with embedded pointer fields.

[kisielk]

sqlx supports embedded structs, but pointers to structs are not followed. This is a bug, because it's contrary to reasonable expectations, ie:

type Foo struct {
    Name string
}

// can set 'Name' on this struct
type Place struct {
    Foo
}

// cannot set 'Name' on this struct
type Person struct {
    *Foo
}

Currently, when you scan into a nil pointer, database/sql allocates the space for you. This is how []byte and string work as well; a new one will always be allocated. I'm going to copy this behavior, even though it's not well known, because I don't want StructScan to behave differently and because I think it could end up creating incredibly difficult to figure out bugs.

The setValues function can allocate these using reflect.

Note that all this per-row allocation is going to cost a little something, so if speed is a priority I recommend against pointer embeds.

[teburd]

Specifically structscan doesn't work with embedded struct pointer fields?

Thats at least the issue I'm having

[kisielk]

Sure, I was just noting from the conversation. If you can post an example here that would be helpful.

[simonklee]

After this patch I receive sql: Scan error on column index 6: destination pointer is nil upon calling StructScan. Just to notify that this brakes some working code. I'll see if I get time for a full bug report later.

[jmoiron]

All embedded pointers should be getting allocated but if you can amend the test case for them to fail that'd help a lot.

[simonklee]

0d135e4 fixed the issue for me.