comparing uncomparable type pgtype.VarcharArray

[bweston92]

To Reproduce

Use a Postgres type varchar[]

Create a query that queries it:

select mytype from mytype;

You'll see something like this in the generated code

// ...

type MyType struct {
	ID                *int32              `json:"id"`
	RemoteIdentifiers pgtype.VarcharArray `json:"remote_identifiers"`
}

// ...
func (tr *typeResolver) newMyType() pgtype.ValueTranscoder {
	return tr.newCompositeValue(
		"mytype",
		compositeField{name: "id", typeName: "int4", defaultVal: &pgtype.Int4{}},
// ...
		compositeField{name: "remote_identifiers", typeName: "_varchar", defaultVal: &pgtype.VarcharArray{}},
// ...
	)
}

Expected behavior

res, err := queries.FindMyType(ctx, 1)
// ...
var ids []string
_ = res.RemoteIdentifiers.AssignTo(&ids)
fmt.Printf("%+v", ids)
// to output a slice of string

Actual behavior

panic: runtime error: comparing uncomparable type pgtype.VarcharArray

goroutine 1 [running]:
github.com/jackc/pgtype.(*VarcharArray).Set(0xc0004e0038, {0xd200a0, 0xc0003f0180})
        external/com_github_jackc_pgtype/varchar_array.go:29 +0x114
github.com/jackc/pgtype.assignToOrSet({0xeaffc0, 0xc0003f0140}, {0xd2b740, 0xc0004e0038})
        external/com_github_jackc_pgtype/composite_type.go:171 +0xa2
github.com/jackc/pgtype.CompositeType.assignToPtrStruct({0x2, {0xd8047e, 0x6}, {0xc00005c200, 0x5, 0x5}, {0xc00051e410, 0x5, 0x5}}, {0xbf5c80, ...})
        external/com_github_jackc_pgtype/composite_type.go:212 +0x3d7
github.com/jackc/pgtype.CompositeType.AssignTo({0x2, {0xd8047e, 0x6}, {0xc00005c200, 0x5, 0x5}, {0xc00051e410, 0x5, 0x5}}, {0xbf5c80, ...})
        external/com_github_jackc_pgtype/composite_type.go:150 +0x1fb

[bweston92]

Error goes away and runs fine if I remove these lines

pgtype/varchar_array.go

Lines 27 to 32 in a4d4bbf

	if value, ok := src.(interface{ Get() interface{} }); ok {
	value2 := value.Get()
	if value2 != value {
	return dst.Set(value2)
	}
	}

[jackc]

There's nothing that someone else can try to run here.

You'll see something like this in the generated code

What do you mean generated code? pgtype doesn't have any code that looks like that.

---

Also, I'd really suggest using pgx v5 instead of v4.

[bweston92]

What do you mean generated code? pgtype doesn't have any code that looks like that.

Sorry I originally wrote this in the context of pgx until I realised the error was in this package.

I will try to get a failing test today if I can reproduce easily.