Inconsistent state of maven-ant-tasks artifact in gradle api

I tried to make my own gradle plugin and I have one problem: gradleApi() provides an ‘org.apache.maven:maven-ant-tasks’ artifact and I can successfully compile my code with any class/interface from this artifact, but in runtime gradle will crash while loading my own class with the next stacktrace:

Caused by: java.lang.ClassNotFoundException: org.apache.maven.artifact.ant.InstallDeployTaskSupport

I have tried other classes from this artifact - same result.

Dump of classpath dependencies also show that no one dependency with ‘ant’ keyword exists in buildscript’s classloader

buildscript.configurations.getByName('classpath').files.findAll { it.absolutePath.contains('ant') }.each { println(it) }

But from other side many classes in gradle impl uses this artifact without any problems.

I tried to manually add this artifact to classpath, but then some plexus functional have broken state.

I think it’s a bug and all artifacts (which provides gradleApi()) should be available in buildscript’s classpath.

The only reliably way to tell if a class loader can load a particular class is to call ‘loadClass’. ‘maven-ant-tasks’ is an internal dependency. The fact that ‘gradleApi()’ brings in too many things is a known limitation. Declaring ‘maven-ant-tasks’ as a build script or plugin dependency sounds like the correct approach.

But if I manually add ‘maven-ant-tasks’ to my classpath i get a verifyerror:

Caused by: java.lang.VerifyError: Bad type on operand stack
Exception Details:
    my.package.Publisher.publish(Lorg/gradle/api/publish/maven/internal/publisher/MavenNormalizedPublication;Lorg/gradle/api/artifacts/repositories/MavenArtifactRepository;)V @35: invokeinterface
    Type 'org/gradle/api/publication/maven/internal/ant/CustomDeployTask' (current frame, stack[1]) is not assignable to 'org/apache/maven/artifact/ant/InstallDeployTaskSupport'
  Current Frame:
    bci: @35
    flags: { }
    locals: { 'my.package.Publisher', 'org/gradle/api/publish/maven/internal/publisher/MavenNormalizedPublication', 'org/gradle/api/artifacts/repositories/MavenArtifactRepository', 'org/gradle/api/publication/maven/internal/ant/CustomDeployTask', 'org/gradle/api/publication/maven/internal/ant/EmptyMavenSettingsSupplier' }
    stack: { 'org/gradle/api/publication/maven/internal/ant/EmptyMavenSettingsSupplier', 'org/gradle/api/publication/maven/internal/ant/CustomDeployTask' }
    0000000: b200 0712 082c b900 0903 002a b600 0a4e
    0000010: 2db8 000b b600 0cbb 000d 59b7 000e 3a04
    0000020: 1904 2db9 000f 0200 2a2d 2cb6 0010 2a2d
    0000030: 2b2a b400 06b4 0011 b700 122a 2db7 0013
    0000040: 1904 b900 1401 00b1

Can you provide a small, self-contained example?


Example of output in ‘example.log’ file.

And yes I know about buildSrc, but it’s more real situation when my plugin is packaged in jar and available for downloading from repositories.