Could not find a field for name (nmcp.internal.task.ArtifactMetadata) metadata/modelVersion

[SimonMarquis]

Expected and Results

Executing publishAllPublicationsToCentralSnapshots lead to this error, after it successfuly uploaded all binaries.
From the logs (of 0.2.1) it seems to happen right after re-fetching the root maven-metadata.xml.

Execution failed for task ':processor:nmcpPublishAllPublicationsToCentralPortalSnapshots'.
> A failure occurred while executing nmcp.internal.task.NmcpPublishFileByFileToSnapshotsWorkAction
   > Could not find a field for name (nmcp.internal.task.ArtifactMetadata) metadata/modelVersion (Attribute)
       candidates: versioning (Element), groupId (Element), artifactId (Element) at position 2:12

Reproduced on both 0.2.1 and 1.0.0.

Here are examples of it on one of my repositories:

• on version 0.2.1
• on version 1.0.0 (here, the entire cache was wiped before running it to rule it out of the equation)

The referenced "missing" field is likely to be this:

nmcp/nmcp/src/main/kotlin/nmcp/internal/task/metadata.kt

Lines 10 to 13 in 053a55e

	@Serializable
	@XmlSerialName("metadata")
	internal data class VersionMetadata(
	val modelVersion: String = "1.1.0",

And here is the maven-metadata.xml fetched (nothing wrong with it):

<metadata modelVersion="1.1.0">
  <groupId>fr.smarquis.sealed</groupId>
  <artifactId>sealed-object-instances</artifactId>
  <versioning>
    <latest>1.11.0-SNAPSHOT</latest>
    <versions>
      <version>1.10.0-SNAPSHOT</version>
      <version>1.11.0-SNAPSHOT</version>
    </versions>
    <lastUpdated>20250601220426</lastUpdated>
  </versioning>
</metadata>

Related environment and versions

No response

Reproduction steps

No response

Anything else?

No response

[SimonMarquis]

Could this be be https://github.com/pdvrieze/xmlutil not retaining non-annotated fields on internal classes, or fields with default values that are ommited by default?

[SimonMarquis]

Actually, it seems like it is ArtifactMetadata that lacks this modelVersion field:

nmcp/nmcp/src/main/kotlin/nmcp/internal/task/metadata.kt

Lines 55 to 63 in 053a55e

	@Serializable
	@XmlSerialName("metadata")
	internal data class ArtifactMetadata(
	@XmlElement
	val groupId: String,
	@XmlElement
	val artifactId: String,
	val versioning: Versioning,
	) {

I'm not sure if this is on purpose (root-level maven-metadata.xml lacking this modelVersion, while version-level maven-metadata.xml having it), but if it is, it means nmcp's snapshot upload generates an invalid maven-metadata.xml file.

[SimonMarquis]

According to the XML schema definition, modelVersion is optional:

<xs:attribute name="modelVersion" type="xs:string" use="optional">

Could we make this parameter optional as well in our Serialization class?

[SimonMarquis]

We can either configure the serializer with this:

internal val xml: StringFormat = XML {
    indent = 2
    defaultPolicy {
        @OptIn(ExperimentalXmlUtilApi::class)
        unknownChildHandler = UnknownChildHandler { _, inputKind, descriptor, name, candidates -> emptyList() }
    }
}

or add the same modelVersion entry to ArtifactMetadata:

@Serializable
@XmlSerialName("metadata")
internal data class ArtifactMetadata(
    val modelVersion: String = "1.1.0",
    @XmlElement
    val groupId: String,
    @XmlElement
    val artifactId: String,
    val versioning: Versioning,
)

[martinbonnin]

I went with your second solution in #147, might as well stay clear of Experimental symbol, plus I believe it makes the parsing more strict overall IMO.

Any chance you can try the snapshots before making a new release?

[SimonMarquis]

I successfully published a snapshot version while using nmcp in version com.gradleup.nmcp.gradle.plugin-1.0.1-20250706.134334-10 👍

> Task :processor:nmcpPublishAllPublicationsToCentralPortalSnapshots
Nmcp: uploading files to https://central.sonatype.com/repository/maven-snapshots/

> Task :processor:publishAllPublicationsToCentralPortalSnapshots

BUILD SUCCESSFUL in 23s

[martinbonnin]

Thanks for confirming, will make 1.0.1 later today