hashicorp/nomad · error

MaxEntries cannot be negative

Error message

MaxEntries cannot be negative

What it means

This error is returned by ControllerListVolumesRequest.Validate when MaxEntries is negative. MaxEntries caps the number of volume entries returned per page; a negative value is meaningless and likely a caller bug (e.g. a signed-int underflow or an uninitialized variable), so it is rejected locally before the gRPC call.

Source

Thrown at plugins/csi/plugin.go:698

type ControllerListVolumesRequest struct {
	MaxEntries    int32
	StartingToken string
}

func (r *ControllerListVolumesRequest) ToCSIRepresentation() *csipbv1.ListVolumesRequest {
	if r == nil {
		return nil
	}
	return &csipbv1.ListVolumesRequest{
		MaxEntries:    r.MaxEntries,
		StartingToken: r.StartingToken,
	}
}

func (r *ControllerListVolumesRequest) Validate() error {
	if r.MaxEntries < 0 {
		return errors.New("MaxEntries cannot be negative")
	}
	return nil
}

type ControllerListVolumesResponse struct {
	Entries   []*ListVolumesResponse_Entry
	NextToken string
}

func NewListVolumesResponse(resp *csipbv1.ListVolumesResponse) *ControllerListVolumesResponse {
	if resp == nil {
		return &ControllerListVolumesResponse{}
	}
	entries := []*ListVolumesResponse_Entry{}
	if resp.Entries != nil {
		for _, entry := range resp.Entries {
			vol := entry.GetVolume()
			status := entry.GetStatus()

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Set MaxEntries to 0 (meaning unspecified/no client-imposed limit per CSI spec) instead of a negative number.
2. Clamp page-size computations with a max(0, n) before assigning MaxEntries.
3. If pagination is desired, use a small positive value (e.g. 100) and iterate with NextToken.
4. Audit the caller for signed arithmetic that can underflow.

Example fix

// before
req := &ControllerListVolumesRequest{MaxEntries: computedSize} // may be -1
// after
if computedSize < 0 { computedSize = 0 }
req := &ControllerListVolumesRequest{MaxEntries: computedSize}

if req.MaxEntries < 0 {
	req.MaxEntries = 0 // 0 = unspecified per CSI spec
}

func validMaxEntries(r *ControllerListVolumesRequest) bool {
	return r != nil && r.MaxEntries >= 0
}

When it happens

Trigger: Calling the list-volumes path with ControllerListVolumesRequest{MaxEntries: -1} — typically from a page-size variable computed as a difference that went negative, or a default set to a signed constant below zero.

Common situations: Pagination math like pageSize := remaining - nextOffset returning a negative; copying a 'no limit' idiom of -1 from another API that rejects it; int truncation from unsigned to signed.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• CSI.ControllerAttachVolume: VolumeID is required
• CSI.ControllerAttachVolume: ClientCSINodeID is required
• CSI.ControllerDetachVolume: VolumeID is required
• CSI.ControllerDetachVolume: ClientCSINodeID is required
• CSI.NodeDetachVolume: PluginID is required

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/4a9e4f5d6e9c29d4. Report an issue: GitHub.