Gradle Module Metadata should not have constraint with null version

[kostya3264]

Expected Behavior

If there is at least one dependency constraint without any version, Gradle Module Metadata should not be generated.
Validation should fail (based on the documentation https://github.com/gradle/gradle/blob/master/subprojects/docs/src/docs/design/gradle-module-metadata-latest-specification.md#variants-value)

Current Behavior

The Gradle Module Metadata can have a dependency constraint without any version. Validation fails only if all constraints don't have a version.

Context

We are trying to add a library which contains dependency constraint with Null version. Our build is failing with the following exception:

  Caused by: org.gradle.internal.resolve.ModuleVersionResolveException: Could not resolve {lib_with_incorrect_dep_constraint}.
  Required by:
     project {project-name}
  Caused by: java.lang.NullPointerException

Is there any way to suppress reading Gradle Module Metadata file from dependency?

Steps to Reproduce

Create a constraints section in build.gradle with several dependencies, at least one of them should have a version, the other one should be without any version (the order doesn't matter), something like this

dependencies {
      constraints {
        implementation 'commons-io:commons-io'
        implementation 'joda-time:joda-time:2.9.9'
    }
}

Your Environment

Gradle 6.9.2

[hegyibalint]

The fix will come with Gradle 7.5: #20182
If we are going to do a 6.9.3, we are also going to fix this issue (#20189).