Deserialized inline tables are serialized as regular tables

[apophizzz]

Hi,
I want to use or library to deserialize Gradle's libs.versions.toml files into some object representation, apply modifications on those objects and serialize them back to files.
Here's a concrete example of what I'm doing:

TOML file:

[versions]
 my-lib = "1.2.3"
            
[libraries]
my-lib = { group = "com.acme.foo", name = "my-lib", version.ref = "my-lib" }

So regarding the file contents, I only know that there will always be two regular tables (versions & libraries) and I know that the keys of the libraries table will always refer to an inline table, but I don't know the key names beforehand. They could match any name.

Decoding classes:

@Serializable
data class VersionsTOML(
    val versions: MutableMap<String, String>,
    val libraries: Map<String, Library> // Can I tell the serializer that Library is a nested inline table somehow?
)

@Serializable
data class Library(val group: String, val name: String, val version: Version)

@Serializable
data class Version(val ref: String)

Decoding the TOML file example shown above works like a charm, but this is actually the result if a serialize the decoded file contents back to a String again:

val tomlContent = """
   [versions]
    my-lib = "1.2.3"
            
   [libraries]
    my-lib = { group = "com.acme.foo", name = "my-lib", version.ref = "my-lib" }
""".trimIndent()

val config = Toml.decodeFromString<VersionsTOML>(tomlContent)
val configString = Toml.encodeToString(config)
println(configString)

That produces:

my-lib = "1.2.3"

[libraries]

[libraries.my-lib]
group = "com.acme.foo"
name = "my-lib"

[libraries.my-lib.version]
ref = "my-lib"

I think this might probably be related to #8. Please let me know in case there's anything I can do differently to make this work or you need anything else from me.
Thx for making this library happening,

Patrick

[eav-eav-eav]

Thanks for your feedback. I see two missing features in your example:

1. Annotate type arguments: unfortunately this is a requested feature in the core, BUT there's one workaround (but not implemented here yet although it's a simple fix) that could make it work: wrap Library with a @JvmInline value class and annotate this value class with TomlInline. My local test succeeds:

   @Serializable
   data class Libraries(val libraries: Map<String, InlineLibrary>)
   
   @TomlInline
   @Serializable
   @JvmInline
   value class InlineLibrary(val library: Library)
   
   @Serializable
   data class Library(val name: String, val version: Version)
   
   @Serializable
   data class Version(val ref: String)

   [libraries]
   my-lib = { name = "my-lib", version = { ref = "my-lib" } }

   And all it takes is just an AnnotationTarget.CLASS:

   @Target(AnnotationTarget.PROPERTY, AnnotationTarget.CLASS)
   public annotation class TomlInline

   BUT I haven't tested if this would work as well in other scenarios.
2. The version.ref part needs another feature, maybe called TomlFlatten, for when you want to flatten a table. This might take some time to get there.