NullPointerException when using Scalafmt.withMavenRepositories from Gradle

[augi]

In gradle-scalafmt, we started using withMavenRepositories method when configuring Scalafmt. Unfortunately, the build then sometimes (esp. in clean environment, without anything cached) fails with following error:

  Caused by: java.lang.NullPointerException: Username must not be null!
  	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:910)
  	at org.gradle.internal.resource.transport.http.ntlm.NTLMCredentials.<init>(NTLMCredentials.java:36)
  	at org.gradle.internal.resource.transport.http.HttpClientConfigurer.useCredentials(HttpClientConfigurer.java:197)
  	at org.gradle.internal.resource.transport.http.HttpClientConfigurer.configureCredentials(HttpClientConfigurer.java:139)
  	at org.gradle.internal.resource.transport.http.HttpClientConfigurer.configure(HttpClientConfigurer.java:109)
  	at org.gradle.internal.resource.transport.http.HttpClientHelper.getClient(HttpClientHelper.java:195)

Also a user of gradle-scalafmt reported this as an issue.

It seems that this happens only if scalafmt is executed before scalaCompile. If scalaCompile goes first then it correctly download all dependencies (to the cache) and scalafmt goes well then as well.

Maybe it is a bug in coursier that is used under the hood?

[olafurpg]

Thank you for reporting! The stack trace doesn’t point to scalafmt, can you please include what Scalafmt method is failing?

[augi]

Sorry for bothering you with this. It seems that it was a strange error in gradle-scalafmt. I don't know why but this change to make the code more Groovish apparently fixed the issue.