Created an attachment (id=1043)
Diff file

As we discussed in the IRC, some minimal error check to make sure configuration builds are running on the same node as the parent build would be great, to make sure the users won't be surprised when they use the distributed builds.

In the future, the error check can be replaced by the copy from the parent workspace to child workspace, which is another often requested feature.

I just realized that those two behaviors aren't exactly the same thing — the latter user might expect Hudson to create a copy of the workspace if two configurations happen to run on the same host, while the original requestor wouldn't like that.

Hmm.

Diff file with discussed changes.
The current node is compared to the parentBuild node, and if different an exception is thrown causing the build to fail.

Updated patch (patch.diff):
useSameScmCheckout will only work on one node.

Added an option to skip checkout on the master, if a user only would like to do the checkouts per-configuration, see duplicated issues.

Thanks. Started looking at the patch now.

Hi, any updates regarding this one?-)

I would like to add a use-case to this particular issue since it's so very close to what I am looking for.

I want the effect of each build slave doing it's own checkout in it's own workspace but with the coherency (i.e. each slave has a guaranteed exact copy of the SCM checkout) and bandwidth (and load on the SCM server) savings of only having a single checkout that each slave uses.

Rather than having each child job do it's own checkout, it would be nice for the child to just get a copy of the parent's SCM checkout.

"Added an option to skip checkout on the master, if a user only would like to do the checkouts per-configuration, see duplicated issues."

Would like to see that implemented. It would make it really nice to not have to check out to three machines, when only two actually do any building...

I updated the patch (patch.diff from January 11th 2010) to current version of Jenkins and created a pull request accordingly:

https://github.com/jenkinsci/jenkins/pull/375/commits

I need this feature badly, since I have to support a huge repository with a rapidly changing set of branches for a fast growing number of platforms.

Code changed in jenkins
User: Thorsten Möllers
Path:
core/src/main/java/hudson/matrix/MatrixProject.java
core/src/main/java/hudson/matrix/MatrixRun.java
core/src/main/java/hudson/model/AbstractBuild.java
core/src/main/resources/hudson/matrix/MatrixProject/configure-entries.jelly
http://jenkins-ci.org/commit/jenkins/3c30e139dec705edfbf51d026a5c5a465e0a379f
Log:
JENKINS-4960: Adapt changes to release jenkins-1.458

Sponsored feature request

This was implemented as an SCMCheckoutStrategy extension point, but we still need someone to deliver the actual implementation of it.

BTW, the real issue has not been fixed (duplicated by https://issues.jenkins-ci.org/browse/JENKINS-13042)
The issue's title and contents are quite different and confusing. I've refactored descriptions in order to represent the current state.

BTW, the strategy should be available in previous LTS releases (1.509.x is mandatory), so it should be implemented as a plugin.

What is the current status of this change, because we need this change too?

roman80 Jenkins core side is done. https://wiki.jenkins-ci.org/display/JENKINS/Extension+points#Extensionpoints-jenkins.scm.SCMCheckoutStrategy
Now somebody should implement a short plugin or maybe just patch matrix project plugin since it's decoupled now.

I'm new to jenkins development, so what can I do to get this done?
What's is so difficult to fix this?
Aren't there some interfaces to implement?

This is a tiny class, add to an own plugin. You can select this checkout strategy, this will skip the axis scm checkouts:

public class NoAxisCheckoutSCMCheckoutStrategyImpl extends SCMCheckoutStrategy {
    @DataBoundConstructor
    public NoAxisCheckoutSCMCheckoutStrategyImpl() {}
    @Extension
    public static class DescriptorImpl extends SCMCheckoutStrategyDescriptor {
        @Override
        public String getDisplayName() {
            return "No axis checkout";
        }
        @Override
        public boolean isApplicable(AbstractProject project) {
            return (project instanceof MatrixProject);
        }
    }
    @Override
    public void checkout(AbstractBuild.AbstractBuildExecution execution) throws IOException, InterruptedException {
        if (execution instanceof MatrixBuild.MatrixBuildExecution) {
            super.checkout(execution);
        }
    }
}