gradle build increases android versionName and versionCode automatically

build.gradle

// major.branchName.revId.commitCount

def pattern = Pattern.compile('versionName=\"(\\d+)\\.(\\w+)\\.(\\w+)\\.(\\d+)\"')

task incrementMajor << {
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine "git", "branch"
        standardOutput = stdout;
    }
    def currentBranch = stdout.toString().trim();

    def manifestFile = file('src/main/AndroidManifest.xml')
    def matcher = pattern.matcher(manifestFile.getText())
    matcher.find()
    def versionName = String.format("%s.%s.%s.%s",
            Integer.parseInt(matcher.group(1)),
            matcher.group(2),
            matcher.group(3),
            Integer.parseInt(matcher.group(4)));
    def manifestContent = matcher.replaceAll('versionName=\"' + versionName + '\"')
    manifestFile.write(manifestContent)
}

task incrementMinor << {
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine "git", "rev-parse", "--abbrev-ref", "HEAD"
        standardOutput = stdout;
    }
    def currentBranch = stdout.toString().trim();

    def manifestFile = file('src/main/AndroidManifest.xml')
    def matcher = pattern.matcher(manifestFile.getText())
    matcher.find()
    def versionName = String.format("%s.%s.%s.%s",
            Integer.parseInt(matcher.group(1)),
            currentBranch,
            matcher.group(3),
            Integer.parseInt(matcher.group(4)));
    def manifestContent = matcher.replaceAll('versionName=\"' + versionName + '\"')
    manifestFile.write(manifestContent)
}

task incrementPatch << {

    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine "git", "log", "-n", "1", "--format='%h'"
        standardOutput = stdout;
    }
    def revid = stdout.toString().trim();

    def manifestFile = file('src/main/AndroidManifest.xml')
    def matcher = pattern.matcher(manifestFile.getText())
    matcher.find()
    def versionName = String.format("%s.%s.%s.%s",
            Integer.parseInt(matcher.group(1)),
            matcher.group(2),
            revid.substring(1, revid.length() - 2),
            Integer.parseInt(matcher.group(4)));
    def manifestContent = matcher.replaceAll('versionName=\"' + versionName + '\"')
    manifestFile.write(manifestContent)
}

task incrementBuild << {

    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine "git", "rev-list", "HEAD", "--count"
        standardOutput = stdout;
    }
    def commitCount = stdout.toString().trim();

    def manifestFile = file('src/main/AndroidManifest.xml')
    def matcher = pattern.matcher(manifestFile.getText())
    matcher.find()
    def versionName = String.format("%s.%s.%s.%s",
            Integer.parseInt(matcher.group(1)),
            matcher.group(2),
            matcher.group(3),
            commitCount);
    def manifestContent = matcher.replaceAll('versionName=\"' + versionName + '\"')
    manifestFile.write(manifestContent)
}

task incrementVersionCode << {
    def manifestFile = file('src/main/AndroidManifest.xml')
    def matcher = Pattern.compile('versionCode=\"(\\d+)\"').matcher(manifestFile.getText())
    matcher.find()
    def manifestContent = matcher.replaceAll('versionCode=\"' +
            ++Integer.parseInt(matcher.group(1)) + '\"')
    manifestFile.write(manifestContent)
}

tasks.whenTaskAdded { task ->
    if (task.name == 'generateReleaseBuildConfig' || task.name == 'generateDebugBuildConfig') {
        task.dependsOn 'incrementMinor'
        task.dependsOn 'incrementPatch'
        task.dependsOn 'incrementBuild'
        task.dependsOn 'incrementVersionCode'
    }
}

produces on build e.g.:

android:versionCode="1"
android:versionName="1.master.431a96.300"