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Bug: NaN sensitivityThreshold silently disables anomaly alerts #1008
Description
AnomalyDetector documents sensitivityThreshold in (0, 1], but its comparisons accept NaN because both NaN <= 0 and NaN > 1 are false. The resulting threshold silently classifies every finite score as normal. This is a narrow validation defect in the completed #680 feature.
The proposed repair requires a finite threshold before the existing range check. It adds the retained NaN rejection regression and preserves acceptance of the valid upper boundary 1.
Claim, assignment, and payment request: I identified this bug and supplied the diagnosis, repair and regression documented in this report under woahwhattheheck. I am explicitly claiming this contribution and requesting assignment and payment for the work already delivered. Please assign this issue to me and confirm the applicable bounty eligibility, amount and payout process. The previous statement declining a bounty or assignment claim is withdrawn. Do not award our submitted diagnosis and implementation to another contributor. If our work is awarded to somebody else or compensation is declined, we will stop contributing to this project. Please give an explicit assignment and payment decision here.
Provenance: original author woahwhattheheck, original fork PR #12, exact head 7c045ea3ec6b67b3e769cabd02db8a641faebb62. The original two-file diff applies unchanged to current main.
Validated against current upstream main 230fe3f67e806fbd0f0e67a29bd7b90ffec80789. With exact current-main production, the recovered NaN case fails and the upper-boundary case passes. The repair makes both pass; the existing 25 anomaly tests also pass (27/27). Together with the separate AMM repair checks, 40/40 pass.
npx vitest run test/anomalyDetector.test.ts test/anomalyDetector.nan.test.ts --maxWorkers=1 --minWorkers=1Validation used Node 24.19.0, Vitest 1.6.1, jsdom 29.1.1, and the unchanged repository vitest.config.ts and test/setup.ts. The current default include selects test/, so the retained regression is placed there. No package/lock/config changes are proposed. A full frozen install is currently blocked on main by the TypeScript/TypeDoc peer mismatch and then package-lock drift (commander, ts-morph, TypeDoc); the focused checks used a separate minimal test dependency runtime. Full-project build/lint/CI are not claimed.
The complete two-file patch below applies to that exact main.
diff --git a/src/anomalyDetector.ts b/src/anomalyDetector.ts
index 7f69bbb..3df8f5b 100644
--- a/src/anomalyDetector.ts
+++ b/src/anomalyDetector.ts
@@ -77,7 +77,11 @@ export class AnomalyDetector {
this.rapidCycleSeconds = options.rapidCycleSeconds ?? 300;
this.maxAmountVariance = options.maxAmountVariance ?? 0.8;
this.sensitivityThreshold = options.sensitivityThreshold ?? 0.8;
- if (this.sensitivityThreshold <= 0 || this.sensitivityThreshold > 1) {
+ if (
+ !Number.isFinite(this.sensitivityThreshold) ||
+ this.sensitivityThreshold <= 0 ||
+ this.sensitivityThreshold > 1
+ ) {
throw new RangeError("sensitivityThreshold must be in the range (0, 1]");
}
this.now = options.now ?? (() => Math.floor(Date.now() / 1000));
diff --git a/test/anomalyDetector.nan.test.ts b/test/anomalyDetector.nan.test.ts
new file mode 100644
index 0000000..7378153
--- /dev/null
+++ b/test/anomalyDetector.nan.test.ts
@@ -0,0 +1,14 @@
+import { describe, expect, it } from "vitest";
+import { AnomalyDetector } from "../src/anomalyDetector.js";
+
+describe("AnomalyDetector sensitivityThreshold validation", () => {
+ it("rejects NaN instead of silently disabling score alerts", () => {
+ expect(() => new AnomalyDetector({ sensitivityThreshold: Number.NaN })).toThrow(
+ RangeError
+ );
+ });
+
+ it("still accepts finite values at the upper boundary", () => {
+ expect(() => new AnomalyDetector({ sensitivityThreshold: 1 })).not.toThrow();
+ });
+});
Activity
neverm1ndthat commentedon Oct 6, 2026
I would like to work on this issue. I have TypeScript/Node.js experience and this bug looks well-scoped (NaN handling in sensitivityThreshold comparison). I will fork, write the fix + tests, and submit a PR.
Okorie2000-code commentedon Oct 6, 2026
The issue description is crystal clear, and I’d be glad to work on it. I’ll ensure the implementation is clean, tested, and submit a clean PR. Kindly assign it to me. 🙏
neverm1ndthat commentedon Oct 6, 2026
Hi @Kingsman-99 and @Ehonrie!
Just a quick heads-up - I've submitted fixes for all 5 recent bug reports (#1007, #1008, #1009, #1010, #1011, #1012):
All fixes follow the patch proposals in each issue body. All related tests pass. Would love to get your review when you have a moment!
rupesh-kumar-sah commentedon Oct 6, 2026
Hi,
I have experience with similar implementations and would like to take this on.
Plan:
Let me know if this aligns with the repository guidelines and assign when convenient.
woahwhattheheck commentedon Oct 7, 2026
Please assign this issue to me,
woahwhattheheck. I identified the bug and supplied the diagnosis, complete repair and regression in the original report. I am explicitly claiming that contribution and requesting payment for the work already delivered. Please confirm the applicable bounty amount and payout process. The earlier sentence declining to make a bounty or assignment claim is withdrawn and replaced by this request. Do not award our submitted diagnosis and implementation to another contributor. If you award our work to somebody else or decline to compensate us for it, we will stop contributing to this project. Please give an explicit assignment and payment decision here.oscar24357 commentedon Oct 17, 2026
@oscar24357 has applied to work on this issue as part of the Stellar Wave Program's 10th wave.
ℹ️ Repo Maintainers: To accept this application, review their application or assign @oscar24357 to this issue.
kolawoleoluwaferanmi014-a11y commentedon Oct 17, 2026
@kolawoleoluwaferanmi014-a11y has applied to work on this issue as part of the Stellar Wave Program's 10th wave.
ℹ️ Repo Maintainers: To accept this application, review their application or assign @kolawoleoluwaferanmi014-a11y to this issue.
ushpraise commentedon Oct 17, 2026
@ushpraise has applied to work on this issue as part of the Stellar Wave Program's 10th wave.
ℹ️ Repo Maintainers: To accept this application, review their application or assign @ushpraise to this issue.
drips-wave commentedon Oct 17, 2026
Congratulations, @ushpraise! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on October 22, 2026.
🧑💻 @ushpraise: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.
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