What causes "value is not valid JSON: %w" in larksuite/cli?

Fix the custom MarshalJSON so it emits well-formed JSON (use json.Marshal on a plain representation inside it).

value is not valid JSON: %w

Error message

value is not valid JSON: %w

What it means

After successfully JSON-encoding the value, valueCompatibleWithShape decodes it via decodeJSONValidationValue to get a normalized JSON document for shape validation; if that decode fails, the value (or its marshaled form) is not valid JSON for validation purposes and this wrapped error is returned.

Source

Thrown at shortcuts/common/typed_compile_contract.go:213

			if !found {
				combined = object
				found = true
			} else if object.AdditionalProperties {
				combined.AdditionalProperties = true
			}
		}
		return combined, found
	}
	return typedObjectShape{}, false
}
func valueCompatibleWithShape(value any, shape typedValueShape) error {
	encoded, err := json.Marshal(value)
	if err != nil {
		return fmt.Errorf("value is not JSON-encodable: %w", err)
	}
	normalized, err := decodeJSONValidationValue(encoded)
	if err != nil {
		return fmt.Errorf("value is not valid JSON: %w", err)
	}
	return validateJSONValueAgainstShape(normalized, shape, "value")
}

View on GitHub (pinned to 7fd6ef3c07)

Solutions

Fix the custom MarshalJSON so it emits well-formed JSON (use json.Marshal on a plain representation inside it).
Replace NaN/Inf values with nil or a sentinel JSON value before validation.
Inspect the wrapped %w cause to find the exact decode failure, then correct the offending value.

Example fix

// before
func (v Value) MarshalJSON() ([]byte, byte) { return []byte(v.Raw), nil } // Raw may be invalid
// after
func (v Value) MarshalJSON() ([]byte, error) { return json.Marshal(v.Raw) }

Defensive patterns

Strategy: validation

Validate before calling

func validMarshalOutput(v json.Marshaler) error {
  b, err := v.MarshalJSON()
  if err != nil { return err }
  var out any
  return json.Unmarshal(b, &out)
}

Prevention

Prefer embedding a plain struct and delegating to json.Marshal inside custom marshalers
Reject NaN/Inf at value construction time
Round-trip test every custom MarshalJSON: marshal then unmarshal

When it happens

Trigger: An override Value whose json.Marshal output is rejected by decodeJSONValidationValue — e.g. a MarshalJSON emitting malformed JSON text, or emitting types the decoder refuses (invalid UTF-8, NaN/Inf smuggled through custom marshaling).

Common situations: Hand-rolled MarshalJSON returning invalid JSON strings; custom marshalers emitting NaN/Infinity for float fields; corrupted values produced by third-party types with buggy marshalers.

Related errors

AI-assisted analysis of larksuite/cli@7fd6ef3c07 (2026-09-04). Data as JSON: /api/errors/cbe60924b26676df. Report an issue: GitHub.