fix: skip invalid locations

v2/pkg/engine/resolve/loader.go

@@ -936,11 +936,47 @@ func (l *Loader) optionallyOmitErrorFields(values []*astjson.Value) {
 
 // optionallyOmitErrorLocations removes the "locations" object from all values.
 func (l *Loader) optionallyOmitErrorLocations(values []*astjson.Value) {
-	if !l.omitSubgraphErrorLocations {
-		return
-	}
 	for _, value := range values {
-		if value.Exists("locations") {
+		// If the flag is set, delete all locations
+		if !value.Exists("locations") || l.omitSubgraphErrorLocations {
+			value.Del("locations")
+			continue
+		}
+
+		locations := value.Get("locations")
+		if locations.Type() != astjson.TypeArray {
+			continue
+		}
+
+		locationsArray := locations.GetArray()
+		locationsClone := slices.Clone(locationsArray)
+
+		deletedEntries := 0
+		locationsArrayLength := len(locationsArray)
+
+		// We loop on a clone since we delete elements inline
+		for i, loc := range locationsClone {
+			line := loc.Get("line")
+			column := loc.Get("column")
+
+			// Skip invalid locations: nil values or values <= 0
+			if line == nil || column == nil {
+				locations.Del(strconv.Itoa(i - deletedEntries))
+				deletedEntries++
+				continue
+			}
+
+			// Keep location only if both line and column are > 0
+			// In case it is not an int, 0 will be returned which is invalid anyway
+			isValid := line.GetInt() > 0 && column.GetInt() > 0
+			if !isValid {
+				locations.Del(strconv.Itoa(i - deletedEntries))
+				deletedEntries++
+			}
+		}
+
+		// If all locations were invalid, delete the locations field
+		if locationsArrayLength == deletedEntries {
 			value.Del("locations")
 		}
 	}