pulumi/pulumi · error

missing __self__ argument properties for provider method cal

Error message

missing __self__ argument properties for provider method call

What it means

When a provider-type method call supplies an `__self__` argument, the engine expects it to be a struct of the provider resource's properties. This error fires when `__self__` exists but its StructValue has no fields (nil field map), so the engine cannot extract the urn/id needed to build the provider reference. It indicates a malformed `__self__` payload rather than a missing one.

Source

Thrown at pkg/resource/deploy/source_eval.go:1261

		parts := strings.Split(tok.Name().String(), "/")
		if len(parts) != 2 {
			return nil, fmt.Errorf("invalid provider method token %v", tok)
		}

		packageName := tokens.Package(parts[0])
		providerReq, err = parseProviderRequest(
			packageName, req.GetVersion(),
			req.GetPluginDownloadURL(), req.GetPluginChecksums(), nil,
		)

		self, ok := req.GetArgs().Fields["__self__"]
		if !ok {
			return nil, errors.New("missing __self__ argument for provider method call")
		}

		selfFields := self.GetStructValue().Fields
		if selfFields == nil {
			return nil, errors.New("missing __self__ argument properties for provider method call")
		}

		provURN, hasProvURN := self.GetStructValue().Fields["urn"]
		if !hasProvURN {
			return nil, errors.New("missing __self__.urn for provider method call")
		}

		provID, hasProvID := self.GetStructValue().Fields["id"]
		if !hasProvID {
			return nil, errors.New("missing __self__.id for provider method call")
		}

		rawProviderRef = fmt.Sprintf("%s::%s", provURN.GetStringValue(), provID.GetStringValue())
	} else if req.Provider != "" {
		rawProviderRef = req.GetProvider()
	} else {
		// Use the provider information from __self__
		args := req.GetArgs()

View on GitHub (pinned to 793f7b2e16)

Solutions

1. Upgrade language SDK and CLI to matched versions so `__self__` is marshaled with urn and id fields
2. Verify the provider resource being passed actually has registered urn/id outputs before the method call
3. If crafting the RPC manually, populate `__self__` as a struct containing at least `urn` and `id` keys
4. File/inspect provider plugin logs to see what was serialized into `__self__`

Example fix

// before
"__self__": structpb.NewStructValue(&structpb.Struct{})
// after
"__self__": structpb.NewStructValue(&structpb.Struct{Fields: map[string]*structpb.Value{
  "urn": structpb.NewStringValue(urn), "id": structpb.NewStringValue(id),
}})

self := req.GetArgs().GetFields()["__self__"]
if self == nil || len(self.GetStructValue().GetFields()) == 0 {
    return fmt.Errorf("__self__ for %q must be a non-empty struct with urn/id", tok)
}

func selfHasFields(v *structpb.Value) bool { return v != nil && len(v.GetStructValue().GetFields()) > 0 }

if err := callMethod(...); strings.Contains(err.Error(), "missing __self__ argument properties") {
    // re-serialize the receiver resource and retry
}

When it happens

Trigger: A ResourceCallRequest where args["__self__"] is present but serializes to an empty/struct-less value (e.g. the value is not a struct, or an empty struct was marshaled for the provider resource); an SDK serializing a provider resource whose outputs are empty and non-serializable into fields.

Common situations: Provider resource created with unknown/placeholder outputs during preview marshaled incorrectly; a buggy or outdated language SDK sending an empty `__self__` struct; hand-built grpc requests passing `structpb.NewStruct(&structpb.Struct{})`.

Related errors

• unmarshaling inputs: %w
• unmarshaling outputs: %w
• missing __self__ argument for provider method call
• missing __self__.urn for provider method call
• missing __self__.id for provider method call

AI-assisted analysis of pulumi/pulumi@793f7b2e16 (2026-08-31). Data as JSON: /api/errors/a9b837f2ebf5eaf0. Report an issue: GitHub.