langflow-ai/langflow · warning · HTTPException

Cannot build deployment artifact: the parent flow for versio

Error message

Cannot build deployment artifact: the parent flow for version '{flow_version.id}' has been deleted or has no name.

What it means

422 raised while building a deployment artifact in the base deployment mapper: the flow version's parent flow row is missing, deleted, or has an empty name, so a valid BaseFlowArtifact (which requires a non-empty name) cannot be constructed. Provider-specific mappers inherit this guard. The version row exists but points at a parent that cannot supply metadata.

Source

Thrown at src/backend/base/langflow/api/v1/mappers/deployments/base.py:246

        *,
        flow_version: FlowVersion,
        flow_row: Flow | None,
        deployment: Deployment,
    ) -> BaseFlowArtifact:
        """Build a ``BaseFlowArtifact`` for a snapshot content update.

        The base implementation assembles the artifact from the flow version
        data and the parent flow's metadata.  Provider-specific mappers
        override this to inject ``provider_data``.

        Raises ``HTTPException(422)`` when the artifact cannot be built
        (e.g. the parent flow has been deleted or the data is malformed).
        """
        from pydantic import ValidationError

        flow_name = getattr(flow_row, "name", None) or ""
        if not flow_name:
            raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
                detail=(
                    f"Cannot build deployment artifact: the parent flow for version "
                    f"'{flow_version.id}' has been deleted or has no name."
                ),
            )
        try:
            return BaseFlowArtifact(
                id=flow_version.flow_id,
                name=flow_name,
                description=getattr(flow_row, "description", None),
                data=flow_version.data,
            )
        except ValidationError as exc:
            raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
                detail=(
                    f"Flow version '{flow_version.id}' cannot be used as a deployment "

View on GitHub (pinned to 976ec789d2)

Solutions

Restore or recreate the parent flow, then re-attach the version
Delete the orphaned flow version row (or the deployment referencing it) and recreate the deployment from a healthy flow
Audit for other orphaned versions pointing at the missing flow id

Defensive patterns

Strategy: validation

Validate before calling

flow = await get_flow(client, flow_version["flow_id"])
if not flow or not flow.get("name"):
    raise ValueError("parent flow missing/nameless — rebuild the version before deploying")

Try / catch

try:
    artifact = await create_deployment(client, version_id)
except httpx.HTTPStatusError as e:
    if e.response.status_code == 422 and "deleted or has no name" in e.response.json()["detail"]:
        prune_orphaned_version(version_id)
    raise

Prevention

Verify the parent flow still exists and is named before deploying any version
Cascade-delete or block deletion of flows that have versions referenced by deployments
Audit for orphaned flow_version rows after DB restores

When it happens

Trigger: Creating/reading a deployment from a flow version whose parent flow was hard-deleted (version row left behind), or whose flow row has name='' — e.g. partial migrations or manual DB edits.

Common situations: Flow deleted while one of its versions was referenced by a deployment; DB restored inconsistently; name stripped by an import/export round-trip.

Related errors

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/d25314c61f4ff68d. Report an issue: GitHub.