{"record":{"id":"0e79294b52557d83","repo":"affaan-m/ECC","slug":"sample-seeds-must-be-unique","errorCode":null,"errorMessage":"sample seeds must be unique","messagePattern":"sample seeds must be unique","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"ecc2/src/harness_eval.rs","lineNumber":531,"sourceCode":"        if !self.min_win_rate.is_finite() || !(0.0..=1.0).contains(&self.min_win_rate) {\n            bail!(\"minimum win rate must be between 0 and 1\");\n        }\n        Ok(())\n    }\n\n    pub fn compare(self, samples: &[PairedSample]) -> Result<Comparison> {\n        self.validate()?;\n        if samples.is_empty() {\n            bail!(\"samples cannot be empty\");\n        }\n        if samples\n            .iter()\n            .map(|sample| sample.seed)\n            .collect::<BTreeSet<_>>()\n            .len()\n            != samples.len()\n        {\n            bail!(\"sample seeds must be unique\");\n        }\n        if samples.iter().any(|s| {\n            !s.candidate_score.is_finite()\n                || !s.baseline_score.is_finite()\n                || !(0.0..=1.0).contains(&s.candidate_score)\n                || !(0.0..=1.0).contains(&s.baseline_score)\n        }) {\n            bail!(\"scores must be finite and between 0 and 1\");\n        }\n        let count = samples.len();\n        let candidate_mean = samples.iter().map(|s| s.candidate_score).sum::<f64>() / count as f64;\n        let baseline_mean = samples.iter().map(|s| s.baseline_score).sum::<f64>() / count as f64;\n        let mean_delta = candidate_mean - baseline_mean;\n        let win_rate = samples\n            .iter()\n            .filter(|s| s.candidate_score > s.baseline_score)\n            .count() as f64\n            / count as f64;","sourceCodeStart":513,"sourceCodeEnd":549,"githubUrl":"https://github.com/affaan-m/ECC/blob/8321021c54d670126ce3b2969d5deb880b4b0c2a/ecc2/src/harness_eval.rs#L513-L549","documentation":"`compare` requires every `PairedSample` to carry a distinct `seed`. Duplicate seeds would double-count the same evaluation case in the mean, delta, and win-rate statistics, silently skewing the comparison. The function collects all seeds into a `BTreeSet` and bails when the set size differs from the slice length.","triggerScenarios":"Calling `compare` with two or more `PairedSample` values whose `seed` field is identical (e.g. samples generated from the same RNG seed).","commonSituations":"A seed generator loop that reuses a constant or a narrow range, samples re-generated for retried runs without advancing the seed, or merging sample lists from two runs that overlapped in seeds.","solutions":["Deduplicate samples by seed before calling compare (keep the last or first occurrence).","Fix the seed generation to produce unique seeds (e.g. unique range or counter-based).","If duplicates represent legitimate repeats, aggregate them into a single PairedSample (e.g. average) before comparing."],"exampleFix":"// before\nevaluator.compare(&samples)?;\n// after\nlet mut seen = std::collections::BTreeSet::new();\nsamples.retain(|s| seen.insert(s.seed));\nevaluator.compare(&samples)?;","handlingStrategy":"validation","validationCode":"let unique: std::collections::BTreeSet<_> = samples.iter().map(|s| s.seed).collect();\nanyhow::ensure!(unique.len() == samples.len(), \"duplicate seeds in samples\");","typeGuard":null,"tryCatchPattern":"match evaluator.compare(&samples) {\n    Ok(c) => c,\n    Err(e) if e.to_string().contains(\"seeds must be unique\") => {\n        eprintln!(\"Deduplicate samples by seed and retry\");\n        return Err(e);\n    }\n    Err(e) => return Err(e),\n}","preventionTips":["Generate seeds from a monotonic counter or checked unique range","Deduplicate merged sample sets by seed before comparison","Unit-test the seed generator for uniqueness"],"tags":["validation","duplicate-data","evaluation-harness"],"backgroundTag":"invalid-argument-value","analyzedSha":"8321021c54d670126ce3b2969d5deb880b4b0c2a","analyzedAt":"2026-09-16T10:08:13.343Z","contentChangedAt":"2026-09-16T10:08:13.343Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}