Gradle file to enforce Semantic Versioning.

build.gradle

apply plugin: "java"

repositories {
  mavenCentral()
}

dependencies {
  compile "org.spockframework:spock-core:0.7-groovy-2.0"
  compile "org.codehaus.groovy:groovy-all:1.8.6"
}

configurations.all {
  incoming.resolutionResult.allDependencies { DependencyResult dependencyResult ->
    if (!SemanticVersion.isMatch(dependencyResult.requested.version) || !SemanticVersion.isMatch(dependencyResult.selected.id.version)) {
      return
    }

    def requested = new SemanticVersion(dependencyResult.requested.version)
    def selected = new SemanticVersion(dependencyResult.selected.id.version)

    if (requested.major != selected.major) {
      throw new Exception("Dependency $dependencyResult has a different selected major version than was requested")
    }
  }
}

class SemanticVersion {
  int major
  int minor
  int patch

  SemanticVersion(String version) {
    (major, minor, patch) = version.split("\\.")
  }

  static boolean isMatch(String version) {
    version ==~ /\d+\.\d+\.\d+/
  }
}