Fix POST/PATCH error on a [{}] json

src/PostgREST/QueryBuilder.hs

@@ -268,7 +268,7 @@ requestToQuery schema isParent (DbRead (Node (Select colSelects tbl tblAlias imp
     --getQueryParts is not total but requestToQuery is called only after addJoinConditions which ensures the only
     --posible relations are Child Parent Many
     getQueryParts _ _ = witness
-requestToQuery schema _ (DbMutate (Insert mainTbl p@(PayloadJSON _ _ pKeys) onConflct putConditions returnings)) =
+requestToQuery schema _ (DbMutate (Insert mainTbl (PayloadJSON _ _ pKeys) onConflct putConditions returnings)) =
   unwords [
     "WITH payload AS (SELECT $1::json AS json_data),",
     "vals AS (",
@@ -276,7 +276,7 @@ requestToQuery schema _ (DbMutate (Insert mainTbl p@(PayloadJSON _ _ pKeys) onCo
      "SELECT json_data AS val FROM payload WHERE json_typeof(json_data) = 'array'",
      "UNION ALL",
      "SELECT json_build_array(json_data) AS val FROM payload WHERE json_typeof(json_data) = 'object')"],
-    "INSERT INTO ", fromQi qi, if payloadIsEmpty then " " else "(" <> cols <> ")",
+    "INSERT INTO ", fromQi qi, if S.null pKeys then " " else "(" <> cols <> ")",
     unwords [
       "SELECT " <> cols <> " FROM",
       "json_populate_recordset", "(null::", fromQi qi, ", (select val from vals)) _",
@@ -293,10 +293,9 @@ requestToQuery schema _ (DbMutate (Insert mainTbl p@(PayloadJSON _ _ pKeys) onCo
   where
     qi = QualifiedIdentifier schema mainTbl
     cols = intercalate ", " $ pgFmtIdent <$> S.toList pKeys
-    payloadIsEmpty = pjIsEmpty p
-requestToQuery schema _ (DbMutate (Update mainTbl p@(PayloadJSON _ _ keys) logicForest returnings)) =
-  if pjIsEmpty p
-    then "WITH " <> ignoredBody <> "SELECT ''"
+requestToQuery schema _ (DbMutate (Update mainTbl (PayloadJSON _ _ keys) logicForest returnings)) =
+  if S.null keys
+    then "WITH " <> ignoredBody <> "SELECT null WHERE false" -- if there are no columns we cannot do UPDATE table SET {empty}, it'd be invalid syntax
     else
       unwords [
         "WITH payload AS (SELECT $1::json AS json_data),",

test/Feature/InsertSpec.hs

@@ -222,12 +222,23 @@ spec = do
           , matchHeaders = ["Location" <:> location]
           }
 
-    context "empty object" $
-      it "successfully populates table with all-default columns" $
+    context "empty objects" $ do
+      it "successfully inserts a row with all-default columns" $ do
         post "/items" "{}" `shouldRespondWith` ""
           { matchStatus  = 201
           , matchHeaders = []
           }
+        post "/items" "[{}]" `shouldRespondWith` ""
+          { matchStatus  = 201
+          , matchHeaders = []
+          }
+
+      it "successfully inserts two rows with all-default columns" $
+        post "/items" "[{}, {}]" `shouldRespondWith` ""
+          { matchStatus  = 201
+          , matchHeaders = []
+          }
+
     context "table with limited privileges" $ do
       it "succeeds if correct select is applied" $
         request methodPost "/limited_article_stars?select=article_id,user_id" [("Prefer", "return=representation")]
@@ -427,20 +438,20 @@ spec = do
             matchHeaders = ["Content-Range" <:> "*/*"]
           }
 
-        get "/items" `shouldRespondWith`
-          [json|[{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15},{id:16},{"id":2},{"id":1}]|]
-          { matchHeaders = [matchContentTypeJson] }
+        request methodPatch "/items" [] [json| [{}] |]
+          `shouldRespondWith` ""
+          {
+            matchStatus  = 204,
+            matchHeaders = ["Content-Range" <:> "*/*"]
+          }
 
-      it "makes no updates and and returns 200, when patching with an empty json object and return=rep" $ do
+      it "makes no updates and and returns 200, when patching with an empty json object and return=rep" $
         request methodPatch "/items" [("Prefer", "return=representation")] [json| {} |]
           `shouldRespondWith` "[]"
           {
             matchStatus  = 200,
             matchHeaders = ["Content-Range" <:> "*/*"]
           }
-        get "/items" `shouldRespondWith`
-          [json| [{"id":3},{"id":4},{"id":5},{"id":6},{"id":7},{"id":8},{"id":9},{"id":10},{"id":11},{"id":12},{"id":13},{"id":14},{"id":15},{id:16},{"id":2},{"id":1}] |]
-          { matchHeaders = [matchContentTypeJson] }
   
     context "with unicode values" $
       it "succeeds and returns values intact" $ do