Add an environment variable to exclude maven from the build.

CHANGES.md

@@ -9,6 +9,8 @@ You might be looking for:
 
 * Ignored `KtLintStepTest`, because [gradle/gradle#11752](https://github.com/gradle/gradle/issues/11752) is causing too many CI failures. ([#499](https://github.com/diffplug/spotless/pull/499))
     * Also fixed a minor problem in TestProvisioner.
+* If you set the environment variable `SPOTLESS_EXCLUDE_MAVEN=true` then the maven plugin will be excluded from the build. ([#502](https://github.com/diffplug/spotless/pull/502))
+    * We have set this in JitPack, as a workaround for [jitpack/jitpack.io#4112](https://github.com/jitpack/jitpack.io/issues/4112)
 
 ### Version 1.26.1 - November 27th 2019 (javadoc [lib](https://diffplug.github.io/spotless/javadoc/spotless-lib/1.26.0/) [lib-extra](https://diffplug.github.io/spotless/javadoc/spotless-lib-extra/1.26.0/), artifact [lib]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib), [lib-extra]([jcenter](https://bintray.com/diffplug/opensource/spotless-lib-extra)))
 

CONTRIBUTING.md

@@ -117,7 +117,7 @@ If you get something running, we'd love to host your plugin within this repo as
 
 ## Integration testing
 
-### Locally
+### Gradle - locally
 
 First, run `./gradlew publishToMavenLocal` in your local checkout of Spotless.  Now, in any other project on your machine, you can use the following snippet in your `settings.gradle` (for Gradle 6.0+).
 
@@ -141,9 +141,9 @@ pluginManagement {
 }
 ```
 
-### Any commit in a public GitHub repo (this one, or any fork)
+### Gradle - any commit in a public GitHub repo (this one, or any fork)
 
-In Gradle 6.0+, you can use the following snippet in your `settings.gradle`.  TODO: broken until [jitpack/jitpack.io#4112](https://github.com/jitpack/jitpack.io/issues/4112) is resolved.
+In Gradle 6.0+, you can use the following snippet in your `settings.gradle`.
 
 ```gradle
 pluginManagement {
@@ -165,6 +165,9 @@ pluginManagement {
   }
 }
 ```
+### Maven
+
+Run `./gradlew publishToMavenLocal` to publish this to your local repository. The maven plugin is not published to JitPack due to [jitpack/jitpack.io#4112](https://github.com/jitpack/jitpack.io/issues/4112).
 
 ## License
 
@@ -173,7 +176,7 @@ By contributing your code, you agree to license your contribution under the term
 All files are released with the Apache 2.0 license as such:
 
 ```
-Copyright 2016 DiffPlug
+Copyright 2020 DiffPlug
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

settings.gradle

@@ -34,4 +34,8 @@ include 'testlib'	// library for sharing test infrastructure between the project
 
 include 'lib-extra'	// reusable library with lots of dependencies
 include 'plugin-gradle'	// gradle-specific glue code
-include 'plugin-maven'	// maven-specific glue code
+
+// excludes maven from JitCI builds,
+if (System.getenv('SPOTLESS_EXCLUDE_MAVEN') != 'true' && System.getenv('JITPACK') != 'true') {
+	include 'plugin-maven'	// maven-specific glue code
+}