Maven and Ivy dependency resolution fails with Gradle 6.0

Question

I have a working project that has a dependency on a maven artifact produced by a peer component like this:

repositories {
   ivy {
       url "../cnf/local"
   }
}

configurations {
  ejbTools
}

dependencies {
  ejbTools 'test:com.ibm.ws.ejbcontainer.fat_tools:1.+'
}

The dependency test:com.ibm.ws.ejbcontainer.fat_tools:1.+ fails to resolve with Gradle 6.0 with the following error:

> Task :com.ibm.ws.ejbcontainer.async_fat:addEJBTools FAILED

FAILURE: Build failed with an exception.

* Where:
Build file '/Users/aguibert/dev/git/open-liberty/dev/com.ibm.ws.ejbcontainer.async_fat/build.gradle' line: 32

* What went wrong:
Execution failed for task ':com.ibm.ws.ejbcontainer.async_fat:addEJBTools'.
> Could not resolve all files for configuration ':com.ibm.ws.ejbcontainer.async_fat:ejbTools'.
   > Could not find any matches for test:com.ibm.ws.ejbcontainer.fat_tools:1.+ as no versions of test:com.ibm.ws.ejbcontainer.fat_tools are available.
     Searched in the following locations:
       - https://repo.maven.apache.org/maven2/test/com.ibm.ws.ejbcontainer.fat_tools/maven-metadata.xml
       - http://public.dhe.ibm.com/ibmdl/export/pub/software/olrepo/test/com.ibm.ws.ejbcontainer.fat_tools/maven-metadata.xml
       - file:/Users/aguibert/dev/git/open-liberty/dev/cnf/local/test/com.ibm.ws.ejbcontainer.fat_tools/
       - file:/Users/aguibert/dev/git/open-liberty/dev/cnf/local/test/com.ibm.ws.ejbcontainer.fat_tools/1.0.33.201909241016/ivy-1.0.33.201909241016.xml
     Required by:
         project :com.ibm.ws.ejbcontainer.async_fat

Context

Currently my project is using Gradle 5.5 and can be built with Java 8, 11, or 12. I am trying to get it working with Java 13 too so I am trying to upgrade to Gradle 6.0.

It seems that there is a general behavior change with the way wildcarded dependencies work in Gradle now (for example com.foo:bar:1.+).

Answer 1

According to this Gradle issue, there is a breaking change in behavior in Gradle 6.0. Before, Gradle would automatically check for artifact metadata (e.g. maven-metadata.xml), but in order to improve performance it seems that Gradle 6.0 no longer does this by default.

There are 2 possible solutions to this problem:

1. Use specific dependency coordinates instead of wildcarded versions like 1.+ (which is best practice IMO)

2. Update the repositories.[maven|ivy].metadataSources configuration. In Gradle 5.X the defaults were:

   repositories {
       maven {
           url "http://repo.mycompany.com/repo"
           metadataSources {
               mavenPom()
               artifact()
           }
       }
       ivy {
           url "http://repo.mycompany.com/repo"
           metadataSources {
               ivyDescriptor()
               artifact()
           }
       }
   }
   

   But in Gradle 6.0 they are now:

   repositories {
       maven {
           url "http://repo.mycompany.com/repo"
           metadataSources {
               mavenPom()
           }
       }
       ivy {
           url "http://repo.mycompany.com/repo"
           metadataSources {
               ivyDescriptor()
           }
       }
   }
   

   So to revert back to previous behavior, add the artifact() configuration to the repositores.[maven|ivy].metadataSources config block.