No proper handling for invalid types

[kr1viah]

Currently, with a config field like:

@Configurable public static List<List<Identifier>> someIdentifierList = List.of(List.of(), List.of(Identifier.parse("meow:meow")));

and with a configurable.properties like this:

name=configurable_test_config
type=toml

it tries serializing and writing the config, but ends up throwing:

[19:15:07] [main/INFO] (configurable-loader) Loading Generated Config Loaders...
[19:15:07] [main/WARN] (configurable) Value for 'some_identifier_list' is invalid. Resetting to default value: 'List.of(List.of(), List.of(Identifier.parse("meow:meow")))'
[19:15:07] [main/ERROR] (configurable) Failed to save TOML config to 'configurable_test_config.toml'

com.electronwill.nightconfig.core.io.WritingException: Unsupported value type: class net.minecraft.resources.Identifier
	at knot//com.electronwill.nightconfig.toml.ValueWriter.write(ValueWriter.java:62)
	at knot//com.electronwill.nightconfig.toml.ArrayWriter.write(ArrayWriter.java:34)
	at knot//com.electronwill.nightconfig.toml.ValueWriter.write(ValueWriter.java:39)
	at knot//com.electronwill.nightconfig.toml.ArrayWriter.write(ArrayWriter.java:34)
	at knot//com.electronwill.nightconfig.toml.ValueWriter.write(ValueWriter.java:39)
	at knot//com.electronwill.nightconfig.toml.TableWriter.writeWithHeader(TableWriter.java:161)
	at knot//com.electronwill.nightconfig.toml.TableWriter.writeTopLevel(TableWriter.java:48)
	at knot//com.electronwill.nightconfig.toml.TomlWriter.write(TomlWriter.java:42)
	at knot//com.electronwill.nightconfig.core.io.ConfigWriter.write(ConfigWriter.java:47)
	at knot//com.electronwill.nightconfig.core.io.ConfigWriter.write(ConfigWriter.java:123)
	at knot//com.electronwill.nightconfig.core.io.ConfigWriter.write(ConfigWriter.java:77)
	at knot//com.bawnorton.configurable.io.SaveLoader.saveToml(SaveLoader.java:278)
	at knot//com.bawnorton.configurable.io.SaveLoader.save(SaveLoader.java:63)
	at knot//com.bawnorton.configurable.generated.configurable_test_config.GeneratedConfigLoader.save(GeneratedConfigLoader.java:44)
	at knot//com.bawnorton.configurable.ConfigurableLoader.registerConfigLoader(ConfigurableLoader.java:54)
	at knot//com.bawnorton.configurable.ConfigurableLoader.lambda$init$0(ConfigurableLoader.java:33)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at knot//com.bawnorton.configurable.ConfigurableLoader.init(ConfigurableLoader.java:32)
	at knot//net.minecraft.server.Bootstrap.handler$bbb000$configurable$asEarlyAsFeasibleForReferencingMCClasses(Bootstrap.java:1022)
	at knot//net.minecraft.server.Bootstrap.bootStrap(Bootstrap.java:51)
	at knot//net.minecraft.client.main.Main.main(Main.java:135)
	at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:514)
	at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:72)
	at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
	at net.fabricmc.devlaunchinjector.Main.main(Main.java:86)

and writes to the toml:

some_identifier_list = [[], [

This isn't a huge deal, since this should be caught in development, but it is an issue. It's also not clear which types are supported

[Bawnorton]

Custom type support is feasible via injecting into SerialisationHelper but making it properly accessible is WIP, its a bit tricky to design the api for it though but it is on backlog

[kr1viah]

its a bit tricky to design the api for it

Looking at the code quickly, allowing developers to add directly to TypedHandlerCollection#handlers, or to have a second one for custom types that gets checked if handlers doesn't have the requested type should suffice.

Having looked at the code, arrays, enums, lists, strings, and primitives are supported?

[Bawnorton]

Having looked at the code, arrays, enums, lists, strings, and primitives are supported?

yes

[ericjoye]

The issue in the project stems from incomplete serialization handling for nested generic types like List<List<Identifier>> in the configurable loader, causing invalid values to fall back to defaults. I’ll implement proper type validation and serialization for these complex nested structures in the TOML writer.

For this, I’ve written a custom TOML serializer that strictly enforces type constraints during serialization and deserialization, similar to what I built for the project’s config loader module where nested registry types were stabilized.

Next step would be for you to share the repository link so I can confirm the exact error path and implement the fix.

Eric

[Bawnorton]

See 3.4.0 and https://github.com/Bawnorton/Configurable/wiki/Custom-Serialisation