RPC returning table alias now works for pg 11/12 (#2737)

The new LATERAL query used for calling the function, introduced on
https://github.com/PostgREST/postgrest/pull/2677, failed on functions
that returned a domain like `CREATE DOMAIN projects_domain AS projects`.

Work around that by changing the query conditionally, by
obtaining a bool that represents the composite alias on the SchemaCache
and only do this on pg 11 and 12.

src/PostgREST/App.hs

@@ -198,7 +198,7 @@ handleRequest AuthResult{..} conf appState authenticated prepared pgVer apiReq@A
 
     (ActionInvoke invMethod, TargetProc identifier _) -> do
       cPlan <- liftEither $ Plan.callReadPlan identifier conf sCache apiReq invMethod
-      resultSet <- runQuery (Plan.crTxMode cPlan) $ Query.invokeQuery (Plan.crProc cPlan) cPlan apiReq conf
+      resultSet <- runQuery (Plan.crTxMode cPlan) $ Query.invokeQuery (Plan.crProc cPlan) cPlan apiReq conf pgVer
       return $ Response.invokeResponse invMethod (Plan.crProc cPlan) apiReq resultSet
 
     (ActionInspect headersOnly, TargetDefaultSpec tSchema) -> do

src/PostgREST/Plan.hs

@@ -56,6 +56,7 @@ import PostgREST.SchemaCache.Identifiers  (FieldName,
                                            Schema)
 import PostgREST.SchemaCache.Proc         (ProcDescription (..),
                                            ProcParam (..), ProcsMap,
+                                           procReturnsCompositeAlias,
                                            procReturnsScalar,
                                            procReturnsSetOfScalar)
 import PostgREST.SchemaCache.Relationship (Cardinality (..),
@@ -550,6 +551,7 @@ callPlan proc ApiRequest{iPreferences=Preferences{..}} paramKeys args readReq =
 , funCArgs = Just args
 , funCScalar = procReturnsScalar proc
 , funCSetOfScalar = procReturnsSetOfScalar proc
+, funCRetCompositeAlias = procReturnsCompositeAlias proc
 , funCReturning = inferColsEmbedNeeds readReq []
 }
   where

src/PostgREST/Plan/CallPlan.hs

@@ -17,12 +17,13 @@ import           PostgREST.SchemaCache.Proc        (ProcDescription (..),
 import Protolude
 
 data CallPlan = FunctionCall
-  { funCQi          :: QualifiedIdentifier
+  { funCQi                :: QualifiedIdentifier
-  , funCParams      :: CallParams
+  , funCParams            :: CallParams
-  , funCArgs        :: Maybe LBS.ByteString
+  , funCArgs              :: Maybe LBS.ByteString
-  , funCScalar      :: Bool
+  , funCScalar            :: Bool
-  , funCSetOfScalar :: Bool
+  , funCSetOfScalar       :: Bool
-  , funCReturning   :: [FieldName]
+  , funCRetCompositeAlias :: Bool
+  , funCReturning         :: [FieldName]
   }
 
 data CallParams

src/PostgREST/Query.hs

@@ -152,15 +152,15 @@ deleteQuery mrPlan apiReq@ApiRequest{..} conf = do
   optionalRollback conf apiReq
   pure resultSet
 
-invokeQuery :: ProcDescription -> CallReadPlan -> ApiRequest -> AppConfig -> DbHandler ResultSet
+invokeQuery :: ProcDescription -> CallReadPlan -> ApiRequest -> AppConfig -> PgVersion -> DbHandler ResultSet
-invokeQuery proc CallReadPlan{crReadPlan, crCallPlan, crBinField} apiReq@ApiRequest{iPreferences=Preferences{..}, ..} conf@AppConfig{..} = do
+invokeQuery proc CallReadPlan{crReadPlan, crCallPlan, crBinField} apiReq@ApiRequest{iPreferences=Preferences{..}, ..} conf@AppConfig{..} pgVer = do
   resultSet <-
     lift . SQL.statement mempty $
       Statements.prepareCall
         (Proc.procReturnsScalar proc)
         (Proc.procReturnsSingleComposite proc)
         (Proc.procReturnsSetOfScalar proc)
-        (QueryBuilder.callPlanToQuery crCallPlan)
+        (QueryBuilder.callPlanToQuery crCallPlan pgVer)
         (QueryBuilder.readPlanToQuery crReadPlan)
         (QueryBuilder.readPlanToCountQuery crReadPlan)
         (shouldCount preferCount)

src/PostgREST/Query/QueryBuilder.hs

@@ -22,6 +22,8 @@ import qualified Hasql.DynamicStatements.Snippet as SQL
 import Data.Tree (Tree (..))
 
 import PostgREST.ApiRequest.Preferences   (PreferResolution (..))
+import PostgREST.Config.PgVersion         (PgVersion, pgVersion110,
+                                           pgVersion130)
 import PostgREST.SchemaCache.Identifiers  (QualifiedIdentifier (..))
 import PostgREST.SchemaCache.Proc         (ProcParam (..))
 import PostgREST.SchemaCache.Relationship (Cardinality (..),
@@ -163,8 +165,8 @@ mutatePlanToQuery (Delete mainQi logicForest range ordts returnings)
     whereLogic = if null logicForest then mempty else " WHERE " <> intercalateSnippet " AND " (pgFmtLogicTree mainQi <$> logicForest)
     (whereRangeIdF, rangeIdF) = mutRangeF mainQi (fst . otTerm <$> ordts)
 
-callPlanToQuery :: CallPlan -> SQL.Snippet
+callPlanToQuery :: CallPlan -> PgVersion -> SQL.Snippet
-callPlanToQuery (FunctionCall qi params args returnsScalar returnsSetOfScalar returnings) =
+callPlanToQuery (FunctionCall qi params args returnsScalar returnsSetOfScalar returnsCompositeAlias returnings) pgVer =
   "SELECT " <> (if returnsScalar || returnsSetOfScalar then "pgrst_call AS pgrst_scalar " else returnedColumns) <> " " <>
   fromCall
   where
@@ -175,7 +177,8 @@ callPlanToQuery (FunctionCall qi params args returnsScalar returnsSetOfScalar re
                          "LATERAL " <> callIt (fmtParams prms)
 
     callIt :: SQL.Snippet -> SQL.Snippet
-    callIt argument = SQL.sql (fromQi qi) <> "(" <> argument <> ") pgrst_call"
+    callIt argument | pgVer < pgVersion130 && pgVer >= pgVersion110 && returnsCompositeAlias = "(SELECT (" <> SQL.sql (fromQi qi) <> "(" <> argument <> ")).*) pgrst_call"
+                    | otherwise                                                              = SQL.sql (fromQi qi) <> "(" <> argument <> ") pgrst_call"
 
     fmtParams :: [ProcParam] -> SQL.Snippet
     fmtParams prms = SQL.sql $ BS.intercalate ", "

src/PostgREST/SchemaCache.hs

@@ -248,6 +248,7 @@ decodeProcs =
                   <*> column HD.text
                   <*> column HD.bool
                   <*> column HD.bool
+                  <*> column HD.bool
                   <*> column HD.bool)
               <*> (parseVolatility <$> column HD.char)
               <*> column HD.bool
@@ -255,15 +256,15 @@ decodeProcs =
     addKey :: ProcDescription -> (QualifiedIdentifier, ProcDescription)
     addKey pd = (QualifiedIdentifier (pdSchema pd) (pdName pd), pd)
 
-    parseRetType :: Text -> Text -> Bool -> Bool -> Bool -> RetType
+    parseRetType :: Text -> Text -> Bool -> Bool -> Bool -> Bool -> RetType
-    parseRetType schema name isSetOf isComposite isVoid
+    parseRetType schema name isSetOf isComposite isVoid isCompositeAlias
       | isVoid    = Single $ Scalar True
       | isSetOf   = SetOf pgType
       | otherwise = Single pgType
       where
         qi = QualifiedIdentifier schema name
         pgType
-          | isComposite = Composite qi
+          | isComposite = Composite qi isCompositeAlias
           | otherwise   = Scalar False
 
     parseVolatility :: Char -> ProcVolatility
@@ -340,6 +341,7 @@ procsSqlQuery pgVer = [q|
      or COALESCE(proargmodes::text[] && '{t,b,o}', false)
     ) AS rettype_is_composite,
     ('void'::regtype = t.oid) AS rettype_is_void,
+    bt.oid <> bt.base as rettype_is_composite_alias,
     p.provolatile,
     p.provariadic > 0 as hasvariadic
   FROM pg_proc p

src/PostgREST/SchemaCache/Proc.hs

@@ -13,6 +13,7 @@ module PostgREST.SchemaCache.Proc
   , procReturnsSingleComposite
   , procReturnsVoid
   , procTableName
+  , procReturnsCompositeAlias
   ) where
 
 import qualified Data.Aeson          as JSON
@@ -25,7 +26,7 @@ import Protolude
 
 data PgType
   = Scalar Bool -- True if the type is void
-  | Composite QualifiedIdentifier
+  | Composite QualifiedIdentifier Bool -- True if the composite is a domain alias(used to work around a bug in pg 11 and 12, see QueryBuilder.hs)
   deriving (Eq, Ord, Generic, JSON.ToJSON)
 
 data RetType
@@ -79,10 +80,16 @@ procReturnsSetOfScalar proc = case proc of
   ProcDescription{pdReturnType = SetOf (Scalar _)} -> True
   _                                                -> False
 
+procReturnsCompositeAlias :: ProcDescription -> Bool
+procReturnsCompositeAlias proc = case proc of
+  ProcDescription{pdReturnType = Single (Composite _ True)} -> True
+  ProcDescription{pdReturnType = SetOf (Composite _ True)}  -> True
+  _                                                         -> False
+
 procReturnsSingleComposite :: ProcDescription -> Bool
 procReturnsSingleComposite proc = case proc of
-  ProcDescription{pdReturnType = Single (Composite _)} -> True
+  ProcDescription{pdReturnType = Single (Composite _ _)} -> True
-  _                                                    -> False
+  _                                                      -> False
 
 procReturnsVoid :: ProcDescription -> Bool
 procReturnsVoid proc = case proc of
@@ -91,6 +98,6 @@ procReturnsVoid proc = case proc of
 
 procTableName :: ProcDescription -> Maybe TableName
 procTableName proc = case pdReturnType proc of
-  SetOf  (Composite qi) -> Just $ qiName qi
+  SetOf  (Composite qi _) -> Just $ qiName qi
-  Single (Composite qi) -> Just $ qiName qi
+  Single (Composite qi _) -> Just $ qiName qi
-  _                     -> Nothing
+  _                       -> Nothing

test/spec/Feature/Query/RpcSpec.hs

@@ -15,7 +15,7 @@ import Text.Heredoc
 import PostgREST.Config.PgVersion (PgVersion, pgVersion100,
                                    pgVersion109, pgVersion110,
                                    pgVersion112, pgVersion114,
-                                   pgVersion130, pgVersion140)
+                                   pgVersion140)
 
 import Protolude  hiding (get)
 import SpecHelper
@@ -376,8 +376,7 @@ spec actualPgVersion =
           ]|]
           { matchHeaders = [matchContentTypeJson] }
 
-      -- https://github.com/PostgREST/postgrest/pull/2677#issuecomment-1444976849
+      when (actualPgVersion >= pgVersion110) $
-      when (actualPgVersion >= pgVersion130) $
         it "can embed if rpc returns domain of table type" $ do
           post "/rpc/getproject_domain?select=id,name,client:clients(id),tasks(id)"
               [json| { "id": 1} |]