gravitational/teleport · error

error in data JSON: %w

Error message

error in data JSON: %w

What it means

JSONMerge in the accessgraph API client validates its inputs by unmarshalling the `data` (base) document into a generic value before applying the patch. If `data` is not valid JSON (syntax error, empty input, trailing garbage), the underlying decode error is wrapped and returned. The merge never runs, so no partial output is produced.

Source

Thrown at lib/accessgraph/apiclient/jsonmerge/jsonmerge.go:40

	"bytes"
	"encoding/json"
	"fmt"
	"strconv"
)

// JSONMerge merges patch into data using the object-merge behavior expected by
// the generated union helpers.
func JSONMerge(data, patch json.RawMessage) (json.RawMessage, error) {
	if data == nil {
		data = []byte(`{}`)
	}
	if patch == nil {
		patch = []byte(`{}`)
	}

	var dataValue any
	if err := unmarshalJSON(data, &dataValue); err != nil {
		return nil, fmt.Errorf("error in data JSON: %w", err)
	}

	var patchValue any
	if err := unmarshalJSON(patch, &patchValue); err != nil {
		return nil, fmt.Errorf("error in patch JSON: %w", err)
	}

	merged, err := json.Marshal(mergeJSON(dataValue, patchValue))
	if err != nil {
		return nil, fmt.Errorf("error writing merged JSON: %w", err)
	}
	return merged, nil
}

func unmarshalJSON(data []byte, value any) error {
	decoder := json.NewDecoder(bytes.NewReader(data))
	decoder.UseNumber()
	return decoder.Decode(value)

View on GitHub (pinned to 1283425b60)

Solutions

1. Validate the `data` payload with json.Valid(data) (or a test unmarshal) before calling JSONMerge; substitute `{}` when empty.
2. Inspect the wrapped decode error (offset/syntax message) to find the exact corrupt position in the input.
3. Trace upstream producers of `data` and fix the serialization/write path that emitted invalid JSON.

Example fix

// before
merged, err := jsonmerge.JSONMerge(data, patch)
// after
if len(bytes.TrimSpace(data)) == 0 { data = []byte("{}") }
if !json.Valid(data) { return nil, fmt.Errorf("invalid base data JSON") }
merged, err := jsonmerge.JSONMerge(data, patch)

if len(bytes.TrimSpace(data)) == 0 { data = []byte("{}") }
if !json.Valid(data) {
	return nil, fmt.Errorf("refusing merge: data is not valid JSON")
}
merged, err := jsonmerge.JSONMerge(data, patch)

func isValidJSON(b []byte) bool { return json.Valid(b) }

merged, err := jsonmerge.JSONMerge(data, patch)
if err != nil {
	if strings.Contains(err.Error(), "error in data JSON") {
		// base document corrupt: log hex/offset, fall back to raw data without merge
	}
}

When it happens

Trigger: Calling JSONMerge (or any MergeActionTeleportProperties/MergeActionAWSProperties/MergeActionAzureProperties/MergeActionGitlabProperties/MergeActionOktaProperties which call it) with a `data` byte slice that is empty, malformed, truncated, or non-JSON content (e.g. YAML or a log line).

Common situations: Access Graph service responses or stored resources that failed to serialize earlier; reading a partially-written file; passing empty/nil-adjacent byte slices when a resource has no recorded properties.

Related errors

• error in patch JSON: %w
• error writing merged JSON: %w
• invalid resize dimensions
• nil certificate override
• invalid public key

AI-assisted analysis of gravitational/teleport@1283425b60 (2026-09-02). Data as JSON: /api/errors/415c29f6b9dd7c0c. Report an issue: GitHub.