From fa99a0b2bfa4ffabb436444b9e171cf18c77206a Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Sat, 31 Jan 2026 13:07:41 +0000
Subject: [PATCH] Add rerun_evaluator/src/rerun_evaluator/core.py

---
 rerun_evaluator/src/rerun_evaluator/core.py | 102 ++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 rerun_evaluator/src/rerun_evaluator/core.py

diff --git a/rerun_evaluator/src/rerun_evaluator/core.py b/rerun_evaluator/src/rerun_evaluator/core.py
new file mode 100644
index 0000000..8d5fcd5
--- /dev/null
+++ b/rerun_evaluator/src/rerun_evaluator/core.py
@@ -0,0 +1,102 @@
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from typing import List, Dict, Any
+import statistics
+import logging
+
+
+# Configure basic logging for CI-ready environments
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+class InvalidRunDataError(ValueError):
+    """Raised when a RunData instance is invalid or has missing/incorrect fields."""
+    pass
+
+
+@dataclass
+class RunData:
+    """Represents a single CI run entry with metadata for rerun evaluation."""
+
+    run_id: str
+    label_triggered: bool
+    flappy: bool
+    pinned: bool
+    unknown_rate: float
+
+    def __post_init__(self) -> None:
+        if not isinstance(self.run_id, str) or not self.run_id:
+            raise InvalidRunDataError("run_id must be a non-empty string")
+        if not isinstance(self.label_triggered, bool):
+            raise InvalidRunDataError("label_triggered must be a bool")
+        if not isinstance(self.flappy, bool):
+            raise InvalidRunDataError("flappy must be a bool")
+        if not isinstance(self.pinned, bool):
+            raise InvalidRunDataError("pinned must be a bool")
+        if not isinstance(self.unknown_rate, (float, int)) or not (0.0 <= self.unknown_rate <= 1.0):
+            raise InvalidRunDataError("unknown_rate must be a float between 0.0 and 1.0")
+
+
+def evaluate_rerun_needs(runs_data: List[RunData]) -> Dict[str, Any]:
+    """Evaluate whether reruns are needed based on CI run historical data.
+
+    Args:
+        runs_data: List of RunData entries.
+
+    Returns:
+        dict: Evaluation metrics for rerun necessity and stability.
+    """
+    assert isinstance(runs_data, list), "runs_data must be a list of RunData instances"
+    if not runs_data:
+        return {
+            "total_runs": 0,
+            "rerun_recommended": False,
+            "metrics": {
+                "label_trigger_rate": 0.0,
+                "flappy_rate": 0.0,
+                "unknown_rate_avg": 0.0,
+                "pinned_rate": 0.0,
+            },
+        }
+
+    # Validate all elements
+    for item in runs_data:
+        if not isinstance(item, RunData):
+            raise InvalidRunDataError("All elements in runs_data must be RunData instances")
+
+    # Compute basic statistics
+    label_triggered_values = [r.label_triggered for r in runs_data]
+    flappy_values = [r.flappy for r in runs_data]
+    pinned_values = [r.pinned for r in runs_data]
+    unknown_rates = [r.unknown_rate for r in runs_data]
+
+    metrics = {
+        "label_trigger_rate": sum(label_triggered_values) / len(runs_data),
+        "flappy_rate": sum(flappy_values) / len(runs_data),
+        "unknown_rate_avg": statistics.fmean(unknown_rates) if unknown_rates else 0.0,
+        "pinned_rate": sum(pinned_values) / len(runs_data),
+    }
+
+    # Simple heuristic for rerun recommendation
+    rerun_recommended = (
+        metrics["flappy_rate"] > 0.2 or
+        metrics["unknown_rate_avg"] > 0.15 or
+        metrics["label_trigger_rate"] < 0.3
+    )
+
+    result = {
+        "total_runs": len(runs_data),
+        "rerun_recommended": bool(rerun_recommended),
+        "metrics": metrics,
+    }
+
+    logger.info(
+        "Rerun evaluation completed: total_runs=%d, rerun_recommended=%s",
+        result["total_runs"],
+        result["rerun_recommended"],
+    )
+
+    return result