jenkinsci/jenkins · error · IllegalArgumentException

Unknown ItemGroup

Error message

Unknown ItemGroup 

What it means

`CopyJobCommand.run()` parses the destination full name; if it contains '/', the prefix before the last '/' is treated as the parent ItemGroup. If `jenkins.getItemByFullName(group)` returns null (no such item), it throws IllegalArgumentException 'Unknown ItemGroup <group>'. The parent folder/group must pre-exist.

Source

Thrown at core/src/main/java/hudson/cli/CopyJobCommand.java:68

    @Argument(metaVar = "DST", usage = "Name of the new job to be created.", index = 1, required = true)
    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility")
    public String dst;

    @Override
    protected int run() throws Exception {
        Jenkins jenkins = Jenkins.get();

        if (jenkins.getItemByFullName(dst) != null) {
            throw new IllegalStateException("Job '" + dst + "' already exists");
        }

        ModifiableTopLevelItemGroup ig = jenkins;
        int i = dst.lastIndexOf('/');
        if (i > 0) {
            String group = dst.substring(0, i);
            Item item = jenkins.getItemByFullName(group);
            if (item == null) {
                throw new IllegalArgumentException("Unknown ItemGroup " + group);
            }

            if (item instanceof ModifiableTopLevelItemGroup) {
                ig = (ModifiableTopLevelItemGroup) item;
            } else {
                throw new IllegalStateException("Can't create job from CLI in " + group);
            }
            dst = dst.substring(i + 1);
        }

        ig.copy(src, dst).save();
        return 0;
    }
}

View on GitHub (pinned to 2e228ff40b)

Solutions

1. Create the parent folder first (Folders plugin / CloudBees Folders): `java -jar jenkins-cli.jar create-job myfolder < folder.xml` or via the UI, then copy into it.
2. Correct the folder name spelling in the destination argument.
3. Copy to a top-level name (no '/') if a folder isn't required.

Example fix

// before:
//   java -jar jenkins-cli.jar copy-job template typo/newjob
//   -> IllegalArgumentException: Unknown ItemGroup typo
//
// after: ensure the folder exists, then copy
//   java -jar jenkins-cli.jar create-job realfolder < folder-config.xml
//   java -jar jenkins-cli.jar copy-job template realfolder/newjob

// For 'folder/name' destinations, verify the parent group exists
int i = dst.lastIndexOf('/');
if (i > 0) {
    String group = dst.substring(0, i);
    if (jenkins.getItemByFullName(group) == null) {
        throw new IllegalArgumentException("Unknown ItemGroup " + group
            + " — create the folder first");
    }
}

When it happens

Trigger: Running `copy-job <src> myfolder/newjob` where 'myfolder' does not exist as an item in Jenkins.

Common situations: Typo in the folder name; expecting the command to create folders on the fly (it does not); targeting a folder path under a nested structure where an intermediate is missing.

Related errors

• Job ' already exists
• Can't create job from CLI in
• Unknown ItemGroup
• Can't create job from CLI in
• Job ' already exists

AI-assisted analysis of jenkinsci/jenkins@2e228ff40b (2026-08-14). Data as JSON: /api/errors/500cfc7e00bac071. Report an issue: GitHub.