Null types

[dafanasev1986]

Currently codec does not support scans of possible null geometries (returns the EOF error).

As a workaround I added this piece of code, but in this case we loose the ability to have non null geometries
(although it should be restricted on the DB side anyway).

func (p binaryScanPlan) Scan(src []byte, target any) error {
        ...
	if src == nil {
		return nil
	}

If you are ok with this sollution please add it, or maybe there is a better one (e.g. separate type like NullGeometry)?

[twpayne]

Currently codec does not support scans of possible null geometries (returns the EOF error).

I tried to duplicate this problem in #2, but as far as I can tell the current code supports converting NULL geometries to Go's nil correctly.

Could you give an example or test case that demonstrates the problem? I would be very happy to fix this.

[dafanasev1986]

Of course, here is an example

func TestCodecDecodeNullGeometry(t *testing.T) {
	defaultConnTestRunner.RunTest(context.Background(), t, func(ctx context.Context, tb testing.TB, conn *pgx.Conn) {
		type s struct {
			Geom geom.T `db:"geom"`
		}

		tb.Helper()
		rows, err := conn.Query(ctx, "select NULL::geometry AS geom", pgx.QueryResultFormats{pgx.BinaryFormatCode})
		assert.NoError(tb, err)

		value, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[s])
		assert.NoError(t, err)
		assert.NotZero(t, value)
		assert.Zero(t, value.Geom)
	})
}

[twpayne]

Thank you for the example. I don't think the test is correct. Specifically, this line:

assert.NotZero(t, value)

value is an interface type. I believe that pgx-geom is correctly setting the underlying value to nil and that this test is incorrectly testing for a nil interface. For more information, see https://groups.google.com/g/golang-nuts/c/wnH302gBa4I.

[dafanasev1986]

I'm sorry, my fault, you can all remove all asserts except the one that tests for the error (assert.NoError(t, err)). The test will still fail

[twpayne]

Thank you for the extra information. I've added support for NULL geometries in #2 and tagged version v0.0.1 which includes the fix.

[dafanasev1986]

Thank you!