[Mongo] Convert bson Decimal128 negative zero to BigInteger zero (#44611)

* Convert bson Decimal128 negative zero to BigInteger zero

modules/drivers/mongo/src/metabase/driver/mongo/conversion.clj

@@ -37,7 +37,11 @@
 
   org.bson.types.Decimal128
   (from-document [^org.bson.types.Decimal128 input _opts]
-    (.bigDecimalValue input))
+    ;; As per https://mongodb.github.io/mongo-java-driver/5.1/apidocs/bson/org/bson/types/Decimal128.html#bigDecimalValue()
+    ;; org.bson.types.Decimal128/POSITIVE_ZERO is convertible to big decimal.
+    (if (.equals input org.bson.types.Decimal128/NEGATIVE_ZERO)
+      0M
+      (.bigDecimalValue input)))
 
   java.util.List
   (from-document [^java.util.List input opts]

modules/drivers/mongo/test/metabase/driver/mongo/conversion_test.clj

@@ -26,3 +26,14 @@
                (-> mseqk mongo.conversion/to-document (mongo.conversion/from-document {:keywordize true}))))
         (is (= mseqs
                (-> mseqs mongo.conversion/to-document (mongo.conversion/from-document nil))))))))
+
+(deftest bson-negative-zero->big-decimal-test
+  (testing "Bson Decimal128 zero is converted to BigDecimal zero"
+    (is (= {"negativeZero" 0M}
+           (mongo.conversion/from-document
+            (org.bson.Document. "negativeZero" org.bson.types.Decimal128/NEGATIVE_ZERO)
+            nil)))
+    (is (= {"positiveZero" 0M}
+           (mongo.conversion/from-document
+            (org.bson.Document. "positiveZero" org.bson.types.Decimal128/POSITIVE_ZERO)
+            nil)))))