# zero-default-getter-membership-review > Review explicit absent-to-zero getter evidence alongside an all-zero-success initial-membership Map decrement. Canonical: https://nightshade.dicksonwu.xyz/rules/zero-default-getter-membership-review.html Release: Nightshade 0.1.1 (v0.1.1) | Field | Value | | --- | --- | | Rule ID | `zero-default-getter-membership-review` | | Severity | info | | Confidence | high | | Maturity | experimental | | Selection | Opt-in | | Policy intent | not required | | Default enabled | no | | Category | Other active opt-ins / Authorization, identity and membership | | Engine facts used | exact-cross-entry-getter, source-key-pattern-binding, all-full-zero-successes, ordered-initial-membership, numeric-map-decrement | | 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 zero-default-getter-membership-review ./.nightshade/node_modules/.bin/nightshade detector show zero-default-getter-membership-review ``` 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 | | ---: | ---: | ---: | ---: | ---: | | 7/7 | 4/4 | 2/2 | 14/14 | 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/zero-default-getter-membership-review.md at v0.1.1. Availability: **opt-in**, no policy required. Severity: **info**. Confidence: **high** for the supported static source relationship. Select with `--detectors zero-default-getter-membership-review`. `zero-default-getter-membership-review` is an opt-in informational source review. It infers neither token-standard semantics nor application policy. The existing `zero-amount-initial-membership` rule continues to require an explicit policy and retains its independent evidence. Admission requires a completed exported numeric getter whose exact histories return the immutable numeric Map lookup when present and explicit numeric zero for absence at every prefix of that lookup chain. Getter histories may not write storage or require unrelated gates. Within the getter, every membership query uses the actual raw parameter or constant operands of the returned lookup; matching types and parameter names do not supply equality. The corresponding spender's ordinary decrement operands select a directly bound exported numeric amount. With only that amount fixed to zero, every full successful history must decrement the same immutable lookup into its exact Map cell and require that cell initially. Ordered mutation/revision proof excludes supplied membership and uncertain origins. A successful zero bypass withholds the finding; a qualified explicit rejection is a quiet control, with no claim of successful zero execution. Cross-entry correspondence uses canonical ledger declaration identity plus ordered literal/raw-parameter key patterns. Parameter roles are alpha-renamed only for this cross-entry comparison, retaining types and repeated-use roles. The finding exposes the original parameter correspondence and does not claim that values from separate transactions are equal. Derived/aggregate operands and wildcard selectors do not qualify. Analysis is isolated from baseline facts, uses exact all-predicate histories, and keeps the existing 40,000-step / 256-path / 50,000-value defaults. This cross-entry pass shares its work/value allowance across relevant entries and admits at most 64 exported entries. An incomplete relevant entry withholds the whole relation and produces rule diagnostics. Ordinary baseline diagnostics and unrelated rules remain independent. Preparation, key roles/selectors, paths, prefixes, absence maps, certificates, helper snapshots and orchestration references consume the shared work/value allowance. Values count cumulative allocations; serialized text uses bounded 64-code-unit chunks and a conservative JSON-escaping reserve. Tight preparation or proof retention budgets produce incomplete coverage before unqualified evidence can be returned. Missing resolved callable/source closure also blocks structural absence. Reporting diagnostics remain available on exhaustion. Finding `initialRequirements` contains only exact raw cell keys along the selected lookup's prefix chain. Additional same-root requirements remain invocation gates and do not appear as supporting selected-chain evidence. Incomplete and rejected inputs provide no absence guarantee. The observer's raw scalar/constant key scope remains explicit above. ## 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 zero-default-getter-membership-review -- 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/zero-default-getter-membership-review.md) - [Catalog entry in rules.json](https://nightshade.dicksonwu.xyz/rules.json) - [All rules](https://nightshade.dicksonwu.xyz/rules.md#authorization-identity-and-membership) - [Limitations](https://nightshade.dicksonwu.xyz/limitations.md)