Bug while serialize class with overridable get-only property using AllPropertiesExtractor

[borovskyav]

I have child class with override get only array of enum's property. While i serialize this, grobuf throws exception like "Hash code collision: members 'BaseClass.States' and 'ChildClass.States' have the same hash code = 15189835799450633671". Proof: https://github.com/borovskyav/GroBuf/commit/eff23cae4997d22ced62ca428e441046fd94a4d2

[borovskyav]

It also does not work with public fields and writable fields. Add tests on it https://github.com/borovskyav/GroBuf/commit/c62f2dfa63c9dbe6e75f6f94c54b195925029c0d

[mr146]

Expiriencing same problems on:

public abstract class Base
{
    protected virtual int Y { get; }
}

public class Derived : Base
{
    protected override int Y => _y;
    private static int _y = 1;
}

However, inlining _y solves problem:

public abstract class Base
{
    protected virtual int Y { get; }
}

public class Derived : Base
{
    protected override int Y => 1;
}

[AndrewKostousov]

@mr146 The following tests are passing on the latest v1.3.2 release:

    [TestFixture]
    public class TestSerializeOnlyOverridableFieldsX
    {
        [Test]
        public void AllPropertiesExtractor()
        {
            var serializer = new Serializer(new AllPropertiesExtractor(), null, GroBufOptions.MergeOnRead);
            var expected = new Derived();
            Assert.DoesNotThrow(() => serializer.Serialize(expected));
        }

        [Test]
        public void PropertiesExtractor()
        {
            var serializer = new Serializer(new PropertiesExtractor(), null, GroBufOptions.MergeOnRead);
            var expected = new Derived();
            Assert.DoesNotThrow(() => serializer.Serialize(expected));
        }

        public abstract class Base
        {
            protected virtual int Y { get; }
        }

        public class Derived : Base
        {
            protected override int Y => _y;
            private static int _y = 1;
        }
    }

Please provide a failing test case if the problem persists.

[AndrewKostousov]

Nonetheless the test case VirtualProperty is failing while test case AbstractProperty is passing:

    public class TestVirtualProps
    {
        [Test]
        public void AbstractProperty()
        {
            var bytes = serializer.Serialize(new DerivedWithAbstractProp(42));
            Assert.That(serializer.Deserialize<DerivedWithAbstractProp>(bytes).Prop, Is.EqualTo(42));
        }

        [Test]
        public void VirtualProperty()
        {
            var bytes = serializer.Serialize(new DerivedWithVirtualProp(42));
            Assert.That(serializer.Deserialize<DerivedWithVirtualProp>(bytes).Prop, Is.EqualTo(42));
        }

        private readonly Serializer serializer = new Serializer(new AllPropertiesExtractor(), null, GroBufOptions.MergeOnRead);

        private abstract class BaseWithVirtualProp
        {
            public virtual int Prop { get; }
        }

        private class DerivedWithVirtualProp : BaseWithVirtualProp
        {
            public DerivedWithVirtualProp(int prop)
            {
                Prop = prop;
            }

            public override int Prop { get; }
        }

        private abstract class BaseWithAbstractProp
        {
            public abstract int Prop { get; }
        }

        private class DerivedWithAbstractProp : BaseWithAbstractProp
        {
            public DerivedWithAbstractProp(int prop)
            {
                Prop = prop;
            }

            public override int Prop { get; }
        }
    }

The problem is in AllPropertiesExtractor which collects "writable" properties from the class and all its ancestors in a rather dumb way. It completely ignores relations between members of types in the class hierarchy considering every type in the hierarchy separately. Hence the collision between properties DerivedWithVirtualProp.Prop and BaseWithVirtualProp.Prop.

[agatlin]

I believe this is still a challenge. I added a new issue, but I believe it is related to this one.