Source generators implementation v1.x.0

[andrewlock]

Initial conversion to source generators.

Changes in version 1.x

Version 0.x of this library used the helper library CodeGeneration.Roslyn by AArnott, for build-time source generation. In version 1.x this approach has been completely replaced in favour of source generators, as these are explicitly supported in .NET 5+. As part of this change, there were a number of additional features added and breaking changes made.

Breaking Changes

• StronglyTypedIds namespace is required. In version 0.x of the library, the [StronglyTypedId] attribute was in the global namespace. In version 1.x, the attribute is in the StronglyTypedIds namespace, so you must add namespace StronglyTypedIds;.
• The properties exposed by StronglyTypedIds have changed: there is no longer a generateJsonConverter property. Instead, this is infered based on the StronglyTypedIdConverters flags provided.
• The String backing typed ID will throw if you call the constructor with a null value

New Features

• The attributes can now auto-generate additional converter types such as EF Core ValueConverter and Dapper TypeHandler, as described in my blog posts. These are optional flags on the converters property.
• Made interface implementations (IEquatable<T> and IComparable<T> currently) optional. This is to potentially support additional interfaces in future versions.
• Added a NullableString backing type. Due to the behaviour of structs in c#, the String backing type ID may still be null, but you can't explicitly call the constructor with a null value. In contrast, you can do this with the NullableString backing type.
• Added a [StronglyTypedIdDefaults] attribute to set default values for all [StronglyTypedId] attributes in your project. This is useful if you want to customise all the attributes, for example, if you want to generate additional converters by default. You can still override all the properties of a [StronglyTypedId] instance.

Bug Fixes

• Some converters had incorrect implementations, such as in (#26). These have been addressed in version 1.x.
• Better null handling has been added for the String backing type, handling issues such as #32.
• The code is marked as auto generated, to avoid errors such as #CS1591 as described in #27