repair single document upserts when using OP_MSG

780df80cfc introduces support for the
OP_MSG protocol. Unfortunately, the upsert and multi options of the
update command still use flagBits to communicate the options, whereas
they must be provided directly into the command document,
alongside the "q" and "v" fields.

This commit:
 - introduces a test for a single-document upsert that, if isolated,
   succeeds against the reference MongoDB 3.6 container, but fails
   against an official 6.0 image.
 - provides a patch that sets the appropriate options.

The test is not perfect as the upsert operation is inherently racy and
this difficult to test. A comfortable threadDelay has been inserted as
a workaround to accomodate for medium workloads.

Database/MongoDB/Internal/Protocol.hs

@@ -494,6 +494,9 @@ data FlagBit =
     | ExhaustAllowed  -- ^ The client is prepared for multiple replies to this request using the moreToCome bit.
     deriving (Show, Eq, Enum)
 
+uOptDoc :: UpdateOption -> Document
+uOptDoc Upsert = ["upsert" =: True]
+uOptDoc MultiUpdate = ["multi" =: True]
 
 {-
   OP_MSG header == 16 byte
@@ -528,7 +531,7 @@ putOpMsg cmd requestId flagBit params = do
                 putCString "documents"               -- identifier
                 mapM_ putDocument iDocuments         -- payload
             Update{..} -> do
-                let doc = ["q" =: uSelector, "u" =: uUpdater]
+                let doc = ["q" =: uSelector, "u" =: uUpdater] <> concatMap uOptDoc uOptions
                     (sec0, sec1Size) =
                       prepSectionInfo
                           uFullCollection

test/QuerySpec.hs

@@ -4,6 +4,7 @@
 module QuerySpec (spec) where
 import Data.String (IsString(..))
 import TestImport
+import Control.Concurrent (threadDelay)
 import Control.Exception
 import Control.Monad (forM_, when)
 import System.Environment (getEnv)
@@ -87,6 +88,21 @@ spec = around withCleanDatabase $ do
       db (count $ select ["name" =: "Yankees", "league" =: "American"] "team") `shouldReturn` 1
       _id `shouldBe` ()
 
+  describe "upsert" $ do
+    it "upserts a document twice with the same spec" $ do
+      let q = select ["name" =: "jack"] "users"
+      db $ upsert q ["color" =: "blue", "name" =: "jack"]
+      -- since there is no way to ask for a ack, we must wait for "a sufficient time"
+      -- for the write to be visible
+      threadDelay 10000
+      db (rest =<< find (select [] "users")) >>= print
+      db (count $ select ["name" =: "jack"] "users") `shouldReturn` 1
+      db $ upsert q ["color" =: "red", "name" =: "jack"]
+      threadDelay 10000
+      db (count $ select ["name" =: "jack"] "users") `shouldReturn` 1
+      Just doc <- db $ findOne (select ["name" =: "jack"] "users")
+      doc !? "color" `shouldBe` Just "red"
+
   describe "insertMany" $ do
     it "inserts documents to the collection and returns their _ids" $ do
       (_id1:_id2:_) <- db $ insertMany "team" [ ["name" =: "Yankees", "league" =: "American"]