# shared-module-once-gate

> Distinct importing module wrappers expose one canonical false-guard then true-write Boolean gate.

Canonical: https://nightshade.dicksonwu.xyz/rules/shared-module-once-gate.html
Release: Nightshade 0.1.1 (v0.1.1)

| Field | Value |
| --- | --- |
| Rule ID | `shared-module-once-gate` |
| Severity | info |
| Confidence | high |
| Maturity | experimental |
| Selection | Opt-in |
| Policy intent | not required |
| Default enabled | no |
| Category | Other active opt-ins / State and collections |
| Engine facts used | resolved-model, canonical-module-identities |
| Release | v0.1.1 |

## Selection and scope

Not selected by default. Select it with `--detectors` or the `detectors` list in nightshade.json. Either one replaces profile selection, so list every rule you want.

```sh
./.nightshade/node_modules/.bin/nightshade ./contracts --detectors shared-module-once-gate
./.nightshade/node_modules/.bin/nightshade detector show shared-module-once-gate
```

The first command runs only this rule; `--detectors` takes a comma-separated list. The second prints the rule's metadata from your installed version.

Severity is review priority. It does not express exploitability or impact. Confidence is detector metadata, not a probability. All built-in rules are experimental.

Compiler scope: the engine supports the pinned profiles 0.28.0, 0.29.0, 0.30.0, 0.31.1, 0.33.0-rc.2, 0.34.0, 0.35.0-rc.1 and 0.35.0, with ZKIR2 by default. Support for this rule can be narrower; the rule documentation below states any narrower scope.

## Corpus checks

Synthetic corpus checks for this rule in the 0.1.1 proof run. A check counts only with compiler acceptance and complete analysis.

| Positive detected | Corrected quiet | Lookalike quiet | Other negative quiet | Incomplete |
| ---: | ---: | ---: | ---: | ---: |
| 2/2 | 2/2 | 2/2 | 1/1 | 0 |

No deviations were recorded for this rule.

These are behavior checks on synthetic fixtures, not a precision or recall estimate. See [evaluation](https://nightshade.dicksonwu.xyz/evaluation.md#synthetic-corpus).

## Rule documentation

From https://github.com/DicksonWu654/nightshade/blob/v0.1.1/docs/detectors/shared-module-once-gate.md at v0.1.1.

Availability: **opt-in** with `--detectors shared-module-once-gate`.
Severity: **info**. Confidence: **high** for the resolved source fact.

Two distinct importing module instances expose direct wrappers calling the same
canonical gate. The supported gate body consists exactly of an assertion that a
Boolean ledger flag is false followed by an assignment of true to that flag.
The assertion message must be parser-confirmed literal data; every operand has
an exact supported shape. Wrappers and gates accept no arguments and return [].
Resolved module, import and call identities distinguish shared gates from
separate instances.
No names or assertion messages establish initialization intent.

A successful gate write contradicts its next false-state guard unless storage is
reset. This does not prove an actual cross-transaction failure, independent
initialization intent, or deployed compiler behavior. Intentional shared
initialization receives the same review finding. Multiple aliases of a single
wrapper module are quiet because they do not create distinct importing modules.
Distinct compiler path/module identities remain distinct even when physical
parsing shares bytes.

## Suppress a match

If a match is intentional, suppress it on the line before with the exact rule ID and a reason of at least eight characters:

```compact
// nightshade-disable-next-line shared-module-once-gate -- Reason this match is intentional
```

Diagnostics cannot be suppressed, and an unmatched directive for a selected rule makes analysis incomplete. See [configuration](https://nightshade.dicksonwu.xyz/configuration.md#suppress-an-intentional-match) for fingerprint suppressions and baselines.

## References

- [Rule source document at v0.1.1](https://github.com/DicksonWu654/nightshade/blob/v0.1.1/docs/detectors/shared-module-once-gate.md)
- [Catalog entry in rules.json](https://nightshade.dicksonwu.xyz/rules.json)
- [All rules](https://nightshade.dicksonwu.xyz/rules.md#state-and-collections)
- [Limitations](https://nightshade.dicksonwu.xyz/limitations.md)