compile(group: 'org.springframework.cloud', name: 'spring-cloud-starter-zookeeper-discovery', version:'2.1.0.RELEASE') { exclude(module: 'zookeeper') }, optional, it's not work

[halower]

 compile(group: 'org.springframework.cloud', name: 'spring-cloud-starter-zookeeper-discovery', version:'2.1.0.RELEASE',optional) {
        exclude(module: 'zookeeper')
    }

it's not work,too

my maven code is

    <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
            <version>${spring-cloud-zookeeper.version}</version>
            <optional>true</optional>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.zookeeper</groupId>
                    <artifactId>zookeeper</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

[shepherdviolet]

'optional' is a closure.... so....

compile(group: 'org.springframework.cloud', name: 'spring-cloud-starter-zookeeper-discovery', version:'2.1.0.RELEASE') {
exclude(module: 'zookeeper')
// Manually call the code in the closure ...........
//project.ext.optionalDeps << it
optionalDeps << it
}