jenkinsci/jenkins · warning · Failure

“{0}” is not an allowed name

Error message

“{0}” is not an allowed name

What it means

Thrown by checkIfNameIsUsed(newName) when, after elevating to SYSTEM2, getItem(newName) returns non-null but the original user could NOT see that item (no DISCOVER permission). To avoid leaking the existence of a hidden item, Jenkins reports the generic 'NotAllowedName' message instead of revealing the collision. This is an intentional information-disclosure guard.

Source

Thrown at core/src/main/java/hudson/model/AbstractItem.java:323

     * Check new name for job
     * @param newName - New name for job.
     */
    private void checkIfNameIsUsed(@NonNull String newName) throws Failure {
        try {
            Item item = getParent().getItem(newName);
            if (item != null) {
                throw new Failure(Messages.AbstractItem_NewNameInUse(newName));
            }
            try (ACLContext ctx = ACL.as2(ACL.SYSTEM2)) {
                item = getParent().getItem(newName);
                if (item != null) {
                    if (LOGGER.isLoggable(Level.FINE)) {
                        LOGGER.log(Level.FINE, "Unable to rename the job {0}: name {1} is already in use. " +
                                "User {2} has no {3} permission for existing job with the same name",
                                new Object[] {this.getFullName(), newName, ctx.getPreviousContext2().getAuthentication().getName(), Item.DISCOVER.name});
                    }
                    // Don't explicitly mention that there is another item with the same name.
                    throw new Failure(Messages.Jenkins_NotAllowedName(newName));
                }
            }
        } catch (AccessDeniedException ex) {
            if (LOGGER.isLoggable(Level.FINE)) {
                LOGGER.log(Level.FINE, "Unable to rename the job {0}: name {1} is already in use. " +
                        "User {2} has {3} permission, but no {4} for existing job with the same name",
                        new Object[] {this.getFullName(), newName, User.current(), Item.DISCOVER.name, Item.READ.name});
            }
            throw new Failure(Messages.AbstractItem_NewNameInUse(newName));
        }
    }

    /**
     * Allows subclasses to block renames for domain-specific reasons. Generic validation of the new name
     * (e.g., null checking, checking for illegal characters, and checking that the name is not in use)
     * always happens prior to calling this method.
     *
     * @param newName the new name for the item

View on GitHub (pinned to 2e228ff40b)

Solutions

1. Grant the user DISCOVER (and ideally READ) permission on the conflicting item if appropriate
2. Choose a different name that does not collide with any hidden item
3. Have an admin perform the rename if the collision is with a restricted item the user should not see
4. Review folder/item security to confirm hidden items are intentional

// Run as SYSTEM to detect hidden collisions without leaking to the user
boolean collides;
try (ACLContext ctx = ACL.as2(ACL.SYSTEM2)) {
    collides = item.getParent().getItem(newName) != null;
}
if (collides) {
    // name collides with a restricted item; suggest a different name without revealing details
}

try {
    // rename flow
} catch (Failure f) {
    if (f.getMessage().contains("not an allowed name")) {
        // likely a hidden collision or disallowed name; suggest alternatives
    }
    throw f;
}

When it happens

Trigger: A user without DISCOVER permission on an existing same-named item attempts to rename to that name; the first getItem (as the user) throws AccessDeniedException or returns null, but the SYSTEM2-elevated getItem finds the hidden item, triggering the NotAllowedName Failure.

Common situations: A lower-privilege user tries to create/rename to a name that collides with a restricted/hidden job they cannot see; folder-level ACLs hide certain items from a user; matrix-based security restricting DISCOVER.

Related errors

• The name “{0}” is already in use.
• Trying to rename an item that does not support this operatio
• New name is not given
• Zip ${zipFile.getPath()} contains illegal file name that bre
• Failed to mkdirs: ${remote}

AI-assisted analysis of jenkinsci/jenkins@2e228ff40b (2026-08-14). Data as JSON: /api/errors/c034b01db285fa49. Report an issue: GitHub.