Is it possible with spring-cloud-contract to work on a contract branch for the producer?

Currently we have a github repo where we store all the contracts, another repo which contains the producer code, and last but not least another one which contains the consumer code.

On the consumer side working with branches when pointing to the contract repo is well supported by using properties like stubrunner.properties.git.branch (more info can be found here https://cloud.spring.io/spring-cloud-contract/reference/html/appendix.html#additional-application-properties)

But on the producer I can not see any way of using the contracts of a concrete branch, we just can point to the github repo where contracts are stored by using contractsRepositoryUrl of the spring-cloud-contract-maven-plugin

This will be very useful to create a flow of contract testing :

a PR to contract testing repo with the proposal
which will trigger the producer job (passing the pr branch name)
if the repo with the contracts contains the bindings, populated by the producer(previous step), then we could trigger the consumer job and validate if everything is fine with these proposed changes
once the 2 builds are green (producer and consumer) we can merge the changes on the contracts repo

UPDATE : the following spring-cloud-contract-maven-plugin config worked for me, also you can set this property through command line like this -Dstubrunner.properties.git.branch=other_branch_than_master

 <plugin>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-contract-maven-plugin</artifactId>
            <version>${spring-cloud-contract.version}</version>
            <extensions>true</extensions>
            <configuration>
                <baseClassMappings>
                    <baseClassMapping>
                        <contractPackageRegex>.*rest.*</contractPackageRegex>
                        <baseClassFQN>com.xxx.yyy.contract.ContentCheckBaseTestClass</baseClassFQN>
                    </baseClassMapping>
                </baseClassMappings>
                <basePackageForTests>com.xxx.yyy.contract</basePackageForTests>

                <contractsRepositoryUrl>git://https://github.com/xxx/yyy.git</contractsRepositoryUrl>
                <contractsRepositoryUsername>${GITHUB_USER}</contractsRepositoryUsername>
                <contractsRepositoryPassword>${GITHUB_TOKEN}</contractsRepositoryPassword>
                <contractsMode>REMOTE</contractsMode>
                <testMode>EXPLICIT</testMode>
                <testFramework>JUNIT5</testFramework>
                    
                <contractsProperties> 
                  <git.branch>another_branch</git.branch>
                </contractsProperties>

                <contractDependency>
                    <groupId>${project.groupId}</groupId>
                    <artifactId>${project.artifactId}</artifactId>
                    <version>${project.version}</version>
                </contractDependency>
            </configuration>
            <executions>
                <execution>
                    <phase>deploy</phase>
                    <goals>
                        <goal>pushStubsToScm</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

Solution

You can reuse the same properties presented here (https://docs.spring.io/spring-cloud-contract/docs/2.2.6.RELEASE/reference/html/appendix.html#additional-application-properties) under the e.g. Spring Cloud Contract Maven's <configuration><contractProperties> section. That way you can pick which branch should be downloaded. Inside the plugin configuration:

<configuration>
    <contractsProperties>
        <git.branch>branchname</git.branch>
    </contractsProperties>
</configuration>