Make it compatible with, and only with Gradle 2.12.

The signature of a Gradle internal API that we use was changed in Gradle
2.12. Such change was not backward compatible, which it makes it very
hard for me to maintain backward compatibility with older Gradle
versions. I have to elevate the minimum required Gradle version to 2.12.

Related changes:
- Needs to upgrade Android plugin to 1.5.0 for it to work with Gradle
  2.12
- Switch away from deprecated Android plugin DSL.

build.gradle

@@ -37,6 +37,7 @@ buildscript {
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:0.5'
         classpath "com.gradle.publish:plugin-publish-plugin:0.9.0"
         classpath 'junit:junit:4.7'
+        classpath 'org.jacoco:org.jacoco.core:0.7.4.201502262128'
     }
 }
 
@@ -70,7 +71,7 @@ dependencies {
 }
 
 task wrapper(type: Wrapper) {
-    gradleVersion = '2.4'
+    gradleVersion = '2.12'
 }
 
 task sourcesJar(type: Jar, dependsOn:classes) {

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Tue Jan 26 11:26:58 PST 2016
+#Tue Mar 15 12:35:16 PDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.4-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.12-bin.zip

gradlew

@@ -42,11 +42,6 @@ case "`uname`" in
     ;;
 esac
 
-# For Cygwin, ensure paths are in UNIX format before anything is touched.
-if $cygwin ; then
-    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
-fi
-
 # Attempt to set APP_HOME
 # Resolve links: $0 may be a link
 PRG="$0"
@@ -61,9 +56,9 @@ while [ -h "$PRG" ] ; do
     fi
 done
 SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >&-
+cd "`dirname \"$PRG\"`/" >/dev/null
 APP_HOME="`pwd -P`"
-cd "$SAVED" >&-
+cd "$SAVED" >/dev/null
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
@@ -114,6 +109,7 @@ fi
 if $cygwin ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
 
     # We build the pattern for arguments to be converted via cygpath
     ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`

gradlew.bat

@@ -46,7 +46,7 @@ echo location of your Java installation.
 goto fail
 
 :init
-@rem Get command-line arguments, handling Windowz variants
+@rem Get command-line arguments, handling Windows variants
 
 if not "%OS%" == "Windows_NT" goto win9xME_args
 if "%@eval[2+2]" == "4" goto 4NT_args

src/main/groovy/com/google/protobuf/gradle/ProtobufPlugin.groovy

@@ -59,14 +59,15 @@ class ProtobufPlugin implements Plugin<Project> {
 
     @Inject
     public ProtobufPlugin(FileResolver fileResolver) {
-      this.fileResolver = fileResolver;
+      this.fileResolver = fileResolver
     }
 
     void apply(final Project project) {
         this.project = project
         def gv = project.gradle.gradleVersion =~ "(\\d*)\\.(\\d*).*"
-        if (!gv || !gv.matches() || gv.group(1).toInteger() < 2 || gv.group(2).toInteger() < 4) {
-            println("You are using Gradle ${project.gradle.gradleVersion}: This version of the protobuf plugin requires minimum Gradle version 2.4")
+        if (!gv || !gv.matches() || gv.group(1).toInteger() != 2 || gv.group(2).toInteger() < 12) {
+            println("You are using Gradle ${project.gradle.gradleVersion}: "
+                    + " This version of the protobuf plugin works with Gradle version 2.12+")
         }
 
         // At least one of the prerequisite plugins must by applied before this plugin can be applied, so
@@ -146,7 +147,7 @@ class ProtobufPlugin implements Plugin<Project> {
      */
     private addSourceSetExtensions() {
       getSourceSets().all {  sourceSet ->
-        sourceSet.extensions.create('proto', ProtobufSourceDirectorySet, project, sourceSet.name, fileResolver)
+        sourceSet.extensions.create('proto', ProtobufSourceDirectorySet, sourceSet.name, fileResolver)
       }
     }
 

src/main/groovy/com/google/protobuf/gradle/ProtobufSourceDirectorySet.groovy

@@ -34,6 +34,7 @@ import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Project
 import org.gradle.api.internal.file.DefaultSourceDirectorySet
 import org.gradle.api.internal.file.FileResolver
+import org.gradle.api.internal.file.collections.DefaultDirectoryFileTreeFactory
 import org.gradle.internal.reflect.Instantiator
 import org.gradle.util.ConfigureUtil
 
@@ -42,8 +43,8 @@ import org.gradle.util.ConfigureUtil
  */
 public class ProtobufSourceDirectorySet extends DefaultSourceDirectorySet {
 
-  public ProtobufSourceDirectorySet(Project project, String name, FileResolver fileResolver) {
-    super(name, String.format("%s Proto source", name), fileResolver)
+  public ProtobufSourceDirectorySet(String name, FileResolver fileResolver) {
+    super(name, String.format("%s Proto source", name), fileResolver, new DefaultDirectoryFileTreeFactory())
     srcDir("src/${name}/proto")
     include("**/*.proto")
   }

testProjectAndroid/build.gradle

@@ -5,8 +5,9 @@ apply plugin: 'com.google.protobuf'
 
 buildscript {
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.3.1'
+        classpath 'com.android.tools.build:gradle:1.5.0'
         classpath 'junit:junit:4.7'
+        classpath 'org.jacoco:org.jacoco.core:0.7.4.201502262128'
     }
 }
 
@@ -24,16 +25,16 @@ android {
     flavorDimensions 'abi', 'version'
     productFlavors {
         freeapp {
-          flavorDimension 'version'
+          dimension 'version'
         }
         retailapp {
-          flavorDimension 'version'
+          dimension 'version'
         }
         x86 {
-          flavorDimension 'abi'
+          dimension 'abi'
         }
         arm {
-          flavorDimension 'abi'
+          dimension 'abi'
         }
     }
     buildTypes {