Prevent unknown nutrition values from appearing as zero

backend/app/services/open_food_facts.py

@@ -57,16 +57,18 @@ def _repair_common_mojibake(text: str) -> str:
     return text
 
 
-def _to_float(value: Any) -> float:
+def _to_float(value: Any) -> float | None:
     if value is None:
-        return 0.0
+        return None
     try:
         result = float(value)
         if not math.isfinite(result):
-            return 0.0
+            return None
+        if result < 0:
+            return None
         return round(result, 2)
     except (TypeError, ValueError):
-        return 0.0
+        return None
 
 
 def _to_optional_text(value: Any) -> str | None:
@@ -135,13 +137,26 @@ async def search_food_products(query: str, page_size: int = 10) -> list[FoodSear
             continue
 
         nutriments = product.get("nutriments") or {}
+        nutrition = {
+            "calories": _to_float(nutriments.get("energy-kcal_100g")),
+            "protein": _to_float(nutriments.get("proteins_100g")),
+            "fat": _to_float(nutriments.get("fat_100g")),
+            "carbohydrates": _to_float(nutriments.get("carbohydrates_100g")),
+        }
+
+        # A missing value is not the same as a measured zero. Incomplete
+        # records are excluded from the loggable search results so CalorieApp
+        # cannot silently turn unknown nutrition into a misleading 0.0 value.
+        if any(value is None for value in nutrition.values()):
+            continue
+
         results.append(
             FoodSearchResult(
                 product_name=product_name,
-                calories=_to_float(nutriments.get("energy-kcal_100g")),
-                protein=_to_float(nutriments.get("proteins_100g")),
-                fat=_to_float(nutriments.get("fat_100g")),
-                carbohydrates=_to_float(nutriments.get("carbohydrates_100g")),
+                calories=nutrition["calories"],
+                protein=nutrition["protein"],
+                fat=nutrition["fat"],
+                carbohydrates=nutrition["carbohydrates"],
                 image_url=_extract_image_url(product),
                 barcode=_to_optional_text(product.get("code")),
                 brand=_extract_brand(product),

backend/tests/test_open_food_facts_normalization.py

@@ -12,10 +12,18 @@
 )
 
 
-@pytest.mark.parametrize("value", [float("inf"), float("-inf"), float("nan"), "Infinity", "NaN"])
-def test_to_float_rejects_non_finite_upstream_values(value: object) -> None:
+@pytest.mark.parametrize(
+    "value",
+    [None, float("inf"), float("-inf"), float("nan"), "Infinity", "NaN", -1],
+)
+def test_to_float_marks_missing_or_invalid_upstream_values_as_unknown(value: object) -> None:
+    assert _to_float(value) is None
+
+
+@pytest.mark.parametrize("value", [0, "0", 12.345])
+def test_to_float_preserves_real_finite_non_negative_values(value: object) -> None:
     result = _to_float(value)
-    assert result == 0.0
+    assert result is not None
     assert math.isfinite(result)
 
 
@@ -30,6 +38,35 @@ def test_extract_nutri_score_only_returns_supported_grades(
     assert _extract_nutri_score({"nutriscore_grade": value}) == expected
 
 
+@patch("app.services.open_food_facts._fetch_primary", new_callable=AsyncMock)
+def test_search_omits_products_with_unknown_nutrition(primary: AsyncMock) -> None:
+    primary.return_value = {
+        "products": [
+            {
+                "product_name": "Incomplete oats",
+                "nutriments": {
+                    "energy-kcal_100g": 375,
+                    "proteins_100g": 13,
+                    "fat_100g": 7,
+                },
+            },
+            {
+                "product_name": "Complete oats",
+                "nutriments": {
+                    "energy-kcal_100g": 375,
+                    "proteins_100g": 13,
+                    "fat_100g": 7,
+                    "carbohydrates_100g": 60,
+                },
+            },
+        ]
+    }
+
+    results = asyncio.run(search_food_products("oats"))
+
+    assert [result.product_name for result in results] == ["Complete oats"]
+
+
 @patch("app.services.open_food_facts._fetch_fallback", new_callable=AsyncMock)
 @patch("app.services.open_food_facts._fetch_primary", new_callable=AsyncMock)
 def test_expected_fallback_failure_becomes_upstream_http_error(

frontend/components/FoodSearchPlaceholder.tsx

@@ -25,9 +25,9 @@ type PortionOption = "whole" | "half" | "quarter" | "custom";
 const SIGN_IN_REQUIRED_LOG_MESSAGE =
   "Your session has expired or you are not signed in. Please sign in again to manage food logs.";
 
-function toNumber(value: unknown): number {
-  if (typeof value !== "number" || Number.isNaN(value)) {
-    return 0;
+function toNumber(value: unknown): number | null {
+  if (typeof value !== "number" || !Number.isFinite(value) || value < 0) {
+    return null;
   }
   return value;
 }
@@ -47,21 +47,34 @@ function toOptionalNumber(value: unknown): number | undefined {
   return value;
 }
 
-function normalizeFoodItem(value: unknown): FoodSearchItem {
+function normalizeFoodItem(value: unknown): FoodSearchItem | null {
   const raw = (value ?? {}) as Record<string, unknown>;
   const productName =
     typeof raw.product_name === "string" && raw.product_name.trim().length > 0
       ? raw.product_name
       : "Unknown food";
+  const calories = toNumber(raw.calories);
+  const protein = toNumber(raw.protein);
+  const fat = toNumber(raw.fat);
+  const carbohydrates = toNumber(raw.carbohydrates);
+
+  if (
+    calories === null ||
+    protein === null ||
+    fat === null ||
+    carbohydrates === null
+  ) {
+    return null;
+  }
 
   return {
     id: toOptionalNumber(raw.id),
     created_at: toOptionalText(raw.created_at),
     product_name: productName,
-    calories: toNumber(raw.calories),
-    protein: toNumber(raw.protein),
-    fat: toNumber(raw.fat),
-    carbohydrates: toNumber(raw.carbohydrates),
+    calories,
+    protein,
+    fat,
+    carbohydrates,
     portion_percentage: toOptionalNumber(raw.portion_percentage),
     image_url: toOptionalText(raw.image_url),
     barcode: toOptionalText(raw.barcode),
@@ -71,6 +84,12 @@ function normalizeFoodItem(value: unknown): FoodSearchItem {
   };
 }
 
+function normalizeFoodItems(values: unknown[]): FoodSearchItem[] {
+  return values
+    .map(normalizeFoodItem)
+    .filter((item): item is FoodSearchItem => item !== null);
+}
+
 function getPortionPercentage(option: PortionOption, customValue: string): number | null {
   if (option === "whole") {
     return 100;
@@ -300,7 +319,7 @@ export function FoodSearchPlaceholder() {
       if (requestId !== logsRequestIdRef.current) {
         return;
       }
-      setLogs((data ?? []).map(normalizeFoodItem));
+      setLogs(normalizeFoodItems(data ?? []));
       setLogError(null);
     } catch (requestError) {
       if (requestId === logsRequestIdRef.current) {
@@ -393,7 +412,7 @@ export function FoodSearchPlaceholder() {
       if (requestId !== searchRequestIdRef.current) {
         return;
       }
-      setResults((data.results ?? []).map(normalizeFoodItem));
+      setResults(normalizeFoodItems(data.results ?? []));
     } catch (requestError) {
       if (!controller.signal.aborted && requestId === searchRequestIdRef.current) {
         setResults([]);
@@ -565,6 +584,9 @@ export function FoodSearchPlaceholder() {
         <p className="mt-1 text-sm text-brand-secondary/80">
           Explore product nutrition data provided by Open Food Facts.
         </p>
+        <p className="mt-1 text-xs text-brand-secondary/70">
+          Only records with complete calorie, protein, fat, and carbohydrate values are shown.
+        </p>
 
         <SearchBar
           query={query}
@@ -591,8 +613,8 @@ export function FoodSearchPlaceholder() {
         {!error && !isLoading && didSearch && !hasResults ? (
           <div className="mt-4">
             <EmptyState
-              title="No matching foods"
-              description="Try a broader query like banana, apple, or oats."
+              title="No complete nutrition records found"
+              description="Try a broader query like banana, apple, or oats. Records with missing nutrition values are not shown."
             />
           </div>
         ) : null}