---
id: LANG-9
family: GR-LANG
level: core
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-lang/lang-9
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# LANG-9 — A JSONPath query never raises; it falls back to the caller's default

*GR-LANG (Part I) · level: core · profiles: runtime · added in 1.0*

## The rule

> **Normative.** This is the rule.
>
> 1. JSONPath evaluation never raises.
>
> 2. A query that is well-formed but matches nothing, and a query that cannot be compiled or cannot be run, both yield the default the caller supplied, null where none was supplied.
>
> 3. The returned value does not tell the two apart.

## Related rules

- Names: LANG-8
- Referenced by: LANG-6

---

Rule identifiers are permanent and are never renumbered. This specification carries
no implementation status: each implementation publishes its own standing against
these rules. Licensed CC BY 4.0.