---
id: INT-8
family: RT-INT
level: extended
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-int/int-8
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# INT-8 — Snapshot validation reports named errors and non-fatal warnings

*RT-INT (Part II) · level: extended · profiles: runtime · added in 1.0*

Validating a snapshot against a workflow definition answers with codes a caller can act on, and draws a hard line between what invalidates a snapshot and what is merely worth saying.

## The rule

> **Normative.** This is the rule.
>
> 1. Validating a snapshot against a workflow definition yields a result carrying named codes.
>
> 2. Errors, each of which makes the result invalid: a version mismatch, raised only when the snapshot's workflow version is non-empty (an empty version skips the check and is not an error); one unknown-node error per snapshot node absent from the definition; and one dependency-not-met error per completed node whose dependency has no recorded state or is neither completed nor skipped.
>
> 3. Warnings, which never make the result invalid: one per definition node missing from the snapshot, and one per completed injected node that has dependencies.


## What it means

Validating a snapshot against a workflow definition treats two kinds of
mismatch very differently. A snapshot node the definition no longer knows —
the graph changed under a run that is trying to resume into it — is an
error: the result is invalid and resuming must not proceed. A definition
node the snapshot has simply not reached yet is only a warning: that is the
ordinary shape of a mid-run snapshot, and a warning must never flip the
result invalid, or every resumable snapshot would be refused.

The version check has an exception worth naming: an empty snapshot version
skips the comparison entirely rather than counting as a mismatch. A snapshot
built with no known version has nothing to compare, and treating "unknown"
as "different" would refuse every such snapshot regardless of the
definition it is checked against.

## Example

The workflow declares two nodes, `node_1` and `node_2`. Only `node_1` has
completed so far.

```json title="A snapshot node the definition does not know" verdict="invalid"
{"id": "unknown_node"}
```

```json title="A definition node the snapshot has not reached yet" verdict="valid"
{"id": "node_2"}
```

```json title="What validation reports for the second case"
{"code": "WARNING_ORPHAN_NODE", "nodeId": "node_2"}
```

The first case invalidates the result; the second is recorded as a warning
and the result stays valid.

## Related rules

- Names: INT-7, INT-14
- Referenced by: INT-7

---

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.