What causes "Cannot use current or descendant project as parent" in theonedev/onedev?

Set parent to a different, existing ancestor-level project (or null for a root project)

theonedev/onedev · error · NotAcceptableException

Cannot use current or descendant project as parent

Error message

Cannot use current or descendant project as parent

What it means

createProject rejects a parent project that is the new project's own subtree: NotAcceptableException 'Cannot use current or descendant project as parent'. Project hierarchy must remain a tree; parenting a project under itself or one of its descendants would create a cycle.

Source

Thrown at server-core/src/main/java/io/onedev/server/rest/resource/ProjectResource.java:292

	
	@SuppressWarnings("unused")
	private static String getDateExample() {
		return DateUtils.formatISO8601Date(new Date());
	}
	
	@Api(order=800, description="Create new project")
    @POST
    public Long createProject(@NotNull @Valid ProjectData data) {
		var project = new Project();
		data.populate(project, projectService);
		
		var subject = SecurityUtils.getSubject();
		var user = SecurityUtils.getUser(subject);

		checkProjectCreationPermission(subject, project.getParent());
	
		if (project.getParent() != null && project.isSelfOrAncestorOf(project.getParent())) 
			throw new NotAcceptableException("Cannot use current or descendant project as parent");
		
		checkProjectNameDuplication(project);		

		if (project.getForkedFrom() != null) {
			var forkedFrom = project.getForkedFrom();
			if (!SecurityUtils.canReadCode(subject, forkedFrom))
				throw new UnauthorizedException("Not authorized to read code of project '" + forkedFrom.getPath() + "'");
			project.getBuildSetting().setBuildPreservations(forkedFrom.getBuildSetting().getBuildPreservations());
			project.getBuildSetting().setCachePreserveDays(forkedFrom.getBuildSetting().getCachePreserveDays());
			project.getBuildSetting().setJobProperties(forkedFrom.getBuildSetting().getJobProperties());
			project.getBuildSetting().setDefaultFixedIssueFilters(forkedFrom.getBuildSetting().getDefaultFixedIssueFilters());
			project.getBuildSetting().setListParams(forkedFrom.getBuildSetting().getListParams(false));
			project.getBuildSetting().setNamedQueries(forkedFrom.getBuildSetting().getNamedQueries());
			project.setPackSetting(forkedFrom.getPackSetting());
			project.setPullRequestSetting(forkedFrom.getPullRequestSetting());
			project.setWorkspaceSetting(forkedFrom.getWorkspaceSetting());
			project.setNamedCommitQueries(forkedFrom.getNamedCommitQueries());
			project.setIssueSetting(forkedFrom.getIssueSetting());

View on GitHub (pinned to d44925c47c)

Solutions

Set parent to a different, existing ancestor-level project (or null for a root project)
When copying a project payload, explicitly clear parent/parentId before POSTing
If the intent was a fork, set forkedFrom instead of parent

Example fix

// before
project.setParent(sourceProject); // source is inside new project's subtree
// after
Project parent = projectService.find("root-team");
project.setParent(Objects.equals(parent, project) ? null : parent);

Defensive patterns

Strategy: validation

Validate before calling

// before POST, ensure parent is not within the new project's subtree
if (parent && (parent.id === project.id || descendantIdsOf(project).includes(parent.id))) {
  throw new Error('parent must not be the project itself or a descendant');
}

Type guard

function safeParent(project, parent) { return parent == null || !isSelfOrAncestorOf(project, parent) ? parent : null; }

Try / catch

try {
  const created = await api.post('/rest/projects', payload);
} catch (e) {
  if (/descendant project as parent/.test(e.message)) {
    payload.parent = null; // or pick another parent, then retry once
  } else throw e;
}

Prevention

Clear parent fields when copying project payloads
Model hierarchy moves explicitly, never copy source parent
Keep a client-side map of project paths to detect subtree relationships
Distinguish forkedFrom from parent in automation code

When it happens

Trigger: POST /rest/projects with a Project whose parent (or parentId) points to a project for which project.isSelfOrAncestorOf(parent) is true — i.e. parent is the same project or a project nested below it. Mainly occurs when copying an existing project's data (e.g. forking/synchronizing) where parent fields are carried along.

Common situations: Cloning a project payload from an existing subproject and re-posting it without clearing/changing parent; automation that derives parent from the source project; importing projects in bulk with stale hierarchy data.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of theonedev/onedev@d44925c47c (2026-09-06). Data as JSON: /api/errors/433e0055b35f4374. Report an issue: GitHub.