JuliusBrussee/caveman · error

cacheengine: invalid array close

Error message

cacheengine: invalid array close

What it means

Thrown by inspectUniqueJSONValue when, after walking all elements of an array, the closing token is not ']'. Like the object-close error, a correct decoder stream cannot reach this with valid JSON; it signals truncated or malformed array structure in the body.

Source

Thrown at cacheengine/native.go:527

			return false, errors.New("cacheengine: invalid object close")
		}
		return found, nil
	case '[':
		if root {
			return false, errors.New("cacheengine: request root must be object")
		}
		found := false
		path = append(path, "*")
		for decoder.More() {
			childFound, err := inspectUniqueJSONValue(decoder, false, depth+1, provider, path)
			if err != nil {
				return false, err
			}
			found = found || childFound
		}
		closing, err := decoder.Token()
		if err != nil || closing != json.Delim(']') {
			return false, errors.New("cacheengine: invalid array close")
		}
		return found, nil
	default:
		return false, errors.New("cacheengine: unexpected delimiter")
	}
}

View on GitHub (pinned to 27d5a3981a)

Solutions

1. Run json.Valid on the body before the engine call and reject early with a clear error
2. Re-marshal instead of byte-editing JSON bodies
3. Verify content-length/body-size accounting in any middleware that rewrites bodies

Example fix

// before
body := raw[:len(raw)-9] // naive tail strip, can cut the closing ']'

// after
var req map[string]any
if err := json.Unmarshal(raw, &req); err != nil { return err }
body, _ := json.Marshal(req)

if !json.Valid(body) { return errors.New("invalid JSON body") }

// n/a

When it happens

Trigger: A body containing an unterminated or wrongly-closed array, e.g. '{"messages":[{"role":"user"}' — combined with streaming-decoder behavior; practically seen with truncated bodies or byte-level body edits.

Common situations: Body truncation by a size-limited proxy; string-surgery on serialized JSON that removes a closing bracket; fixtures with mismatched brackets from templating.

Related errors

• cacheengine: invalid object close
• cacheengine: request root must be object
• cacheengine: duplicate or invalid object key
• cacheengine: JSON nesting limit exceeded
• cacheengine: unexpected delimiter

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/161d10df4109d361. Report an issue: GitHub.