Config validation & compilation

To validate your mapping in unit tests and in order to help with "Fail Fast" situations, the following strict mapping modes have been added.

Explicit Mapping

Forcing all classes to be explicitly mapped:

//Default is "false"
TypeAdapterConfig.GlobalSettings.RequireExplicitMapping = true;
//This means you have to have an explicit configuration for each class, even if it's just:
TypeAdapterConfig<Source, Destination>.NewConfig();

Checking Destination Member

Forcing all destination properties to have a corresponding source member or explicit mapping/ignore:

//Default is "false"
TypeAdapterConfig.GlobalSettings.RequireDestinationMemberSource = true;

Validating Mappings

Both a specific TypeAdapterConfig<Source, Destination> or all current configurations can be validated. In addition, if Explicit Mappings (above) are enabled, it will also include errors for classes that are not registered at all with the mapper.

//Validate a specific config
var config = TypeAdapterConfig<Source, Destination>.NewConfig();
config.Compile();

//Validate globally
TypeAdapterConfig<Source, Destination>.NewConfig();
TypeAdapterConfig<Source2, Destination2>.NewConfig();
TypeAdapterConfig.GlobalSettings.Compile();

Config Compilation

Mapster will automatically compile mapping for first time usage.

var result = poco.Adapt<Dto>();

However, you can explicitly compile mapping by Compile method.

//Global config
TypeAdapterConfig.GlobalSettings.Compile();

//Config instance
var config = new TypeAdapterConfig();
config.Compile();

After compile, when you change setting in config, it will generate errors. Therefore, make sure you finish configuration before calling Compile.

Calling Compile method on start up has following benefits.

1. Validate mapping: as describe in previous section, Compile method helps you validate mapping. Calling on start up, help you detect problem on start-up time, not on run-time.
2. Prevent compilation error on runtime: Mapster is thread-safe for Adapt method after compilation. But not before compilation. In some corner case, you might got compilation error when calling Adapt method concurrently with TypeAdapterConfig setup.