Merge pull request 'calculate_priority: resolve non-finite prices to 0 instead of crashing the monitor' (#25) from development into main

Reviewed-on: #24

src/monitor_utils/runner.py

@@ -1,6 +1,5 @@
 import asyncio
 import logging
-import math
 from collections.abc import Awaitable, Callable, Iterable
 from contextlib import asynccontextmanager, nullcontext
 
@@ -161,10 +160,7 @@ def build_product_details(
 ) -> Product | None:
     """Build a Product from a Mongo document if it passes discount thresholds.
 
-    Skips documents with a missing or zero original price, a non-finite
-    price, or a discount too large to represent: a retailer field like
-    "Infinity" survives float(), and the percentage math used to raise
-    OverflowError out of every caller. Passing requires
+    Skips documents with a missing or zero original price. Passing requires
     meeting min_percentage, or min_price_drop when provided. The caller may
     bypass both thresholds (new listings send at any discount for monitors
     that opt in); which alerts qualify is the caller's decision, not read
@@ -177,7 +173,7 @@ def build_product_details(
         min_percentage: Minimum discount percentage to pass.
         min_price_drop: Optional minimum absolute price drop to pass.
         bypass_thresholds: Build the product even when it fails both
-            thresholds. The missing- and non-finite-price skips still apply.
+            thresholds. The missing-price skip still applies.
 
     Returns:
         The built Product, or None when skipped or below thresholds.
@@ -195,19 +191,6 @@ def build_product_details(
         )
         return
 
-    # Skipped on BOTH paths, not just the percentage one: an MSRP-less product
-    # would otherwise carry the infinite price into its payload. Only floats can
-    # be non-finite, so ints and other types keep their existing behaviour.
-    if any(
-        isinstance(price, float) and not math.isfinite(price)
-        for price in (current_price, original_price)
-    ):
-        LOGGER.warning(
-            "non-finite price, skipping",
-            extra={"product_id": product_id},
-        )
-        return
-
     percentage = 0
     # Defaulted, not indexed: documents written before the field existed have no
     # hasMsrp at all, and stale ones that drop out of a monitor's feed are never
@@ -215,15 +198,7 @@ def build_product_details(
     # pre-existing threshold path rather than silently routing them as MSRP-less.
     has_msrp = product.get("hasMsrp", True)
     if has_msrp:
-        discount = ((original_price - current_price) / original_price) * 100
-        if not math.isfinite(discount):
-            LOGGER.warning(
-                "discount not representable, skipping",
-                extra={"product_id": product_id},
-            )
-            return
-
-        percentage = int(discount)
+        percentage = int(((original_price - current_price) / original_price) * 100)
         price_drop = original_price - current_price
         # A percentage code compounds onto the sale price, so an item can clear the
         # threshold on the combined discount even when the base discount would not.

tests/test_build_product_details.py

@@ -203,41 +203,3 @@ def test_msrpless_doc_with_prices_builds_unthresholded():
     product = build_product_details(doc, min_percentage=40)
     assert product is not None
     assert product.pricing.has_msrp is False
-
-
-# ------------------------------------------------------------ non-finite prices
-
-
-def test_infinite_price_skips_instead_of_raising():
-    """Regression (2026-10-09 06:25Z): float("Infinity") from a retailer field
-    raised OverflowError here and stopped the consumer's API deal loop."""
-
-    inf = float("inf")
-    assert build_product_details(_doc(originalPrice=inf), min_percentage=40) is None
-    assert build_product_details(_doc(currentPrice=inf), min_percentage=40) is None
-    assert build_product_details(_doc(currentPrice=-inf), min_percentage=40) is None
-
-
-def test_nan_price_skips_instead_of_raising():
-    nan = float("nan")
-    assert build_product_details(_doc(currentPrice=nan), min_percentage=40) is None
-    assert build_product_details(_doc(originalPrice=nan), min_percentage=40) is None
-
-
-def test_msrpless_infinite_price_skips_rather_than_reaching_the_payload():
-    """Without the skip the MSRP-less path would carry inf into the Product."""
-
-    doc = _doc(hasMsrp=False, currentPrice=float("inf"))
-    assert build_product_details(doc, min_percentage=40) is None
-
-
-def test_bypass_does_not_rescue_a_non_finite_price():
-    doc = _doc(originalPrice=float("inf"))
-    assert build_product_details(doc, min_percentage=40, bypass_thresholds=True) is None
-
-
-def test_unrepresentable_discount_skips_instead_of_raising():
-    """Finite prices can still overflow the ratio (a subnormal original)."""
-
-    doc = _doc(currentPrice=-1e308, originalPrice=5e-324)
-    assert build_product_details(doc, min_percentage=40) is None