Editing an IOpenApiSchema

[rwb196884]

I was doing this sort of thing

public class SchemaFilter : ISchemaFilter
{
        public void Apply(IOpenApiSchema schema, SchemaFilterContext context)
        {
            List<PropertyInfo> properties = context.Type.GetProperties().ToList();

            foreach (KeyValuePair<string, OpenApiSchema> p in schema.Properties ?? new Dictionary<string, IOpenApiSchema>())
            {
                PropertyInfo pi = properties.Single(z => string.Equals(z.Name, p.Key, StringComparison.InvariantCultureIgnoreCase));
                StringLengthAttribute? asl = pi.GetCustomAttribute<StringLengthAttribute>();
                if (asl != null)
                {
                    pv.MaxLength = asl.MaximumLength;
                }
        }
    }
}

However this has been broken in version 10 because OpenApiSchema has been replaced by IOpenApiSchema which is not editable.

I couldn't find anything about this in the upgrade notes, and I haven't been able to find a workaround.

Can it work or do I need to stay on version 9?

[Youssef Fahmy (Youssef1313)]

Vincent Biret (@baywet) Was it considered to keep the property setters in the interfaces?

rwb196884 You can achieve that today by doing a type check. In all common cases, the instance will be of type OpenApiSchema.

[Vincent Biret (baywet)]

here is essentially the solution

public class SchemaFilter : ISchemaFilter
{
        public void Apply(IOpenApiSchema schema, SchemaFilterContext context)
        {
            List<PropertyInfo> properties = context.Type.GetProperties().ToList();

-            foreach (KeyValuePair<string, OpenApiSchema> pv in schema.Properties ?? new Dictionary<string, IOpenApiSchema>())
+            foreach (var pv in schema.Properties ?? new Dictionary<string, IOpenApiSchema>())
            {
+               if (pv.Value is not OpenApiSchema targetSchema) continue;
                PropertyInfo pi = properties.Single(z => string.Equals(z.Name, p.Key, StringComparison.InvariantCultureIgnoreCase));
                StringLengthAttribute? asl = pi.GetCustomAttribute<StringLengthAttribute>();
                if (asl != null)
                {
_                    pv.Value.MaxLength = asl.MaximumLength;
+                    targetSchema.MaxLength = asl.MaximumLength;
                }
        }
    }
}

Youssef Fahmy (@Youssef1313) we coudln't. That's an intentional change if you compare with how references are handed in v1. A lot of people ended up mutating the target value when they didn't intend to. This requirement of making a type assertion is here so that consumers evaluate whether they want to change inline schemas, the reference target, or both.