StackoverflowException on attribute groups

[budul100]

Hi, when I am converting the yEd-graphML source xsd, then it comes to a StackoverflowException. I am calling the generator with the following parameters:

-n http://graphml.graphdrawing.org/xmlns=GraphML -n http://www.w3.org/1999/xlink=XLink -n http://www.yworks.com/xml/graphml=YEd --nu --sf --csm=Public --ct=System.Array --dc ".\ygraphml.xsd"

The problem is an infinite loop in the CreatePropertiesForAttributes function of the model builder.

The problem appears on line 804 ff in ModelBuilder.cs:

if (attributeGroup.RedefinedAttributeGroup != null)
{
	foreach (var attr in attributeGroup.RedefinedAttributeGroup.Attributes.Cast<XmlSchemaObject>())
	{
		var n = attr.GetQualifiedName();

		if (n != null)
			attributes.RemoveAll(a => a.GetQualifiedName() == n);

		attributes.Add(attr);
	}
}

If the item determination is replaced by the following line, then the problem is not appearing anymore (similar approach as line 800 in ModelBuilder.cs:

if (attributeGroup.RedefinedAttributeGroup != null)
{
	var attrs = attributeGroup.RedefinedAttributeGroup.Attributes.Cast<XmlSchemaObject>()
		.Where(a => !(a is XmlSchemaAttributeGroupRef agr && agr.RefName == attributeGroupRef.RefName)).ToList();

	foreach (var attr in attrs)
	{
		var n = attr.GetQualifiedName();

		if (n != null)
			attributes.RemoveAll(a => a.GetQualifiedName() == n);

		attributes.Add(attr);
	}
}

[budul100]

Actually, I am afraid, that the solution is not really solving the issue. It is rather cutting the output without considering the references.

[budul100]

The solution in the meantime was to extend the AttributeGroups and the Groups variable of ModelBuilder:

[...]

private readonly Dictionary<XmlQualifiedName, HashSet<XmlSchemaAttributeGroup>> AttributeGroups = new();
private readonly Dictionary<XmlQualifiedName, HashSet<XmlSchemaGroup>> Groups = new();

[...]

foreach (var schema in set.Schemas().Cast<XmlSchema>())
	ResolveDependencies(schema, dependencyOrder, seenSchemas);

foreach (var schema in dependencyOrder)
{
	var currentAttributeGroups = schema.AttributeGroups.Values.Cast<XmlSchemaAttributeGroup>()
		.DistinctBy(g => g.QualifiedName.ToString());

	foreach (var currentAttributeGroup in currentAttributeGroups)
	{
		if (!AttributeGroups.ContainsKey(currentAttributeGroup.QualifiedName))
		{
			AttributeGroups.Add(currentAttributeGroup.QualifiedName, new HashSet<XmlSchemaAttributeGroup>());
		}

		AttributeGroups[currentAttributeGroup.QualifiedName].Add(currentAttributeGroup);
	}

	var currentSchemaGroups = schema.Groups.Values.Cast<XmlSchemaGroup>()
		.DistinctBy(g => g.QualifiedName.ToString());

	foreach (var currentSchemaGroup in currentSchemaGroups)
	{
		if (!Groups.ContainsKey(currentSchemaGroup.QualifiedName))
		{
			Groups.Add(currentSchemaGroup.QualifiedName, new HashSet<XmlSchemaGroup>());
		}

		Groups[currentSchemaGroup.QualifiedName].Add(currentSchemaGroup);
	}
}

foreach (var schema in dependencyOrder)
{
	foreach (var globalType in set.GlobalTypes.Values.Cast<XmlSchemaType>().Where(s => s.GetSchema() == schema))
		CreateTypeModel(globalType.QualifiedName, globalType);

	foreach (var rootElement in set.GlobalElements.Values.Cast<XmlSchemaElement>().Where(s => s.GetSchema() == schema))
		CreateElement(rootElement);
}

The CreatePropertiesForAttributes function has to be changed as follows:

private IEnumerable<PropertyModel> CreatePropertiesForAttributes(Uri source, TypeModel owningTypeModel, IEnumerable<XmlSchemaObject> items)
{
	var properties = new List<PropertyModel>();

	foreach (var item in items)
	{
		switch (item)
		{
			case XmlSchemaAttribute attribute when attribute.Use != XmlSchemaUse.Prohibited:

				properties.Add(PropertyFromAttribute(owningTypeModel, attribute));
				break;

			case XmlSchemaAttributeGroupRef attributeGroupRef:

				foreach (var attributeGroup in AttributeGroups[attributeGroupRef.RefName])
				{
					if (_configuration.GenerateInterfaces)
						CreateTypeModel(attributeGroupRef.RefName, attributeGroup);

					var attributes = attributeGroup.Attributes.Cast<XmlSchemaObject>()
						.Where(a => !(a is XmlSchemaAttributeGroupRef agr && agr.RefName == attributeGroupRef.RefName))
						.ToList();

					if (attributeGroup.RedefinedAttributeGroup != null)
					{
						var attrs = attributeGroup.RedefinedAttributeGroup.Attributes.Cast<XmlSchemaObject>()
							.Where(a => !(a is XmlSchemaAttributeGroupRef agr && agr.RefName == attributeGroupRef.RefName)).ToList();

						if (attrs.Any(a => (a is XmlSchemaAttributeGroupRef agr && agr.RefName == attributeGroupRef.RefName))) { }

						foreach (var attr in attrs)
						{
							var n = attr.GetQualifiedName();

							if (n != null)
								attributes.RemoveAll(a => a.GetQualifiedName() == n);

							attributes.Add(attr);
						}
					}

					var newProperties = CreatePropertiesForAttributes(source, owningTypeModel, attributes);
					properties.AddRange(newProperties);
				}

				break;
		}
	}
	return properties;
}

And the functions had to be adjusted:

private void AddInterfaces(ReferenceTypeModel refTypeModel, IEnumerable<Particle> items)
{
	var interfaces = items.Select(i => i.XmlParticle).OfType<XmlSchemaGroupRef>()
		.Select(i => (InterfaceModel)builder.CreateTypeModel(i.RefName, builder.Groups[i.RefName].First()));
	refTypeModel.AddInterfaces(interfaces);
}

private void AddInterfaces(ReferenceTypeModel refTypeModel, XmlSchemaObjectCollection attributes)
{
	var interfaces = attributes.OfType<XmlSchemaAttributeGroupRef>()
		.Select(a => (InterfaceModel)builder.CreateTypeModel(a.RefName, builder.AttributeGroups[a.RefName].First()));
	refTypeModel.AddInterfaces(interfaces);
}

That has solved the problem.

[mganss]

Thanks a lot. I have integrated your changes. You're also welcome to contribute code by creating a pull request. That way, you are credited as the author of the code changes in the project's history and it makes the workflow easier.