Schema-derived types will have their default constructors stripped by Unity's Managed code stripping setting medium or above

Unity has a feature called managed code stripping to reduce the size of a build. During this process, if the setting is set to Medium or High, all types derived from Colyseus.Schema.Schema will have their default constructors stripped because Unity’s linker determine that they are unreachable code, which leads to MissingMethodException during runtime handshaking.

Schema-derived types include all types generated by schema-codegen and also the built-in types used by Colyseus Unity client such as Colyseus.Schema.ReflectionField, Colyseus.Schema.ReflectionType and Colyseus.Schema.Reflection.

While adding the UnityEngine.Scripting.Preserve attribute to each Schema-derived types will preserve their default constructors, it will lead to a “Local schema mismatch from server” exception on High managed code stripping setting, which technically is a different issue from this, but until there is an official fix, the safe option for users of Colyseus Unity client for now is to build with managed code stripping setting set to Low or disabled.

[tonygiang]

Not so fast. This issue affects all C# types generated by schema-codegen. It will be fixed when schema-codegen is fixed.

[endel]

Relevant to this discussion, a Discord user has reported this comment: (building for Android)

i can’t compile il2cpp because unity only has low striping for il2cpp and not disable… but it works on Mono backend which has the disable function stripping