CHANGES_SINCE_LAST_SUCCESS actually uses CHANGES for some things, I think showDependencies should work fine for CHANGES_SINCE_LAST_SUCCESS. Let me review the code for showDependencies, that was implemented before I took over the plugin.

Thanks for checking.

This is what it does for showDependencies, I'm not real familiar with this code, so I can't comment on what exactly it should do

for (Entry<AbstractProject, DependencyChange> e : build.getDependencyChanges(previousBuild).entrySet()) {
    buf.append("\n=======================\n");
    buf.append("\nChanges in ").append(e.getKey().getName())
        .append(":\n");
    for (AbstractBuild<?, ?> b : e.getValue().getBuilds()) {
        for (ChangeLogSet.Entry entry : b.getChangeSet()) {
            Util.printf(buf, format, new ChangesSincePrintfSpec(entry, pathFormat, dateFormatter));
        }
    }
}

I am running into a similar issue with

Jenkins: 1.548
email-ext: 2.37.2

However, for me the email-ext plugin will return changes with dependencies IF the build ends with a FAILURE. If the build is unstable the changes will not be populated. Here are the settings I am using:

${CHANGES, showDependencies=true, format="[%a] %d, %r: %m
n %p
n"}

showDependencies uses the following code:

for (Entry<AbstractProject, DependencyChange> e : build.getDependencyChanges(previousBuild).entrySet()) {
    buf.append("\n=======================\n");
    buf.append("\nChanges in ").append(e.getKey().getName()).append(":\n");
    for (AbstractBuild<?, ?> b : e.getValue().getBuilds()) {
        for (ChangeLogSet.Entry entry : b.getChangeSet()) {
            Util.printf(buf, format, new ChangesSincePrintfSpec(entry, pathFormat, dateFormatter));
        }
    }
}

AbstractBuild.getDependencyChanges returns an EMPTY Map if there is no Fingerprinter.FingerprintAction for the project. The showDependencies is all based on core Jenkins classes, so you'd need to determine if your projects are meeting the requirements for the dependency graph being populated.

Thanks for your comment, Alex. I checked the dependency graph and it is populated correctly. However, in the job that has the test failures I am copying test artifacts around. Not sure if that is the problem, I enabled fingerprinting of the copied artifacts to no avail. The fact that the dependent changes are shown correctly IF the job does not complete (no tests run) but does not show dependent changes IF the job completes unstable (tests are run with some failing) indicates that the root cause could be the copying of files. I will try to investigate further and see if I can get it working.