From d9777b43b8f0e4f60bc590d5b98db7b6dbf2af76 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Tue, 9 May 2023 16:58:43 +0200
Subject: [PATCH 01/15] feat: add basic UPDATE .. RETURNING * for Postgres

With #44 as a starting point, and more ideas in mind.
---
 src/Database/Esqueleto/Internal/Internal.hs | 41 +++++++++++++++++++--
 src/Database/Esqueleto/PostgreSQL.hs        | 10 +++++
 test/PostgreSQL/Test.hs                     | 12 ++++++
 3 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index e46516e30..497f15fe9 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -427,6 +427,10 @@ locking kind = putLocking $ LegacyLockingClause kind
 putLocking :: LockingClause -> SqlQuery ()
 putLocking clause = Q $ W.tell mempty { sdLockingClause = clause }
 
+-- | (Internal) Remember a @RETURNING@ clause in a query
+tellReturning :: ReturningClause -> SqlQuery ()
+tellReturning clause = Q $ W.tell mempty { sdReturningClause = clause }
+
 {-#
   DEPRECATED
     sub_select
@@ -1835,14 +1839,15 @@ data SideData = SideData
     , sdLimitClause    :: !LimitClause
     , sdLockingClause  :: !LockingClause
     , sdCteClause      :: ![CommonTableExpressionClause]
+    , sdReturningClause :: !ReturningClause
     }
 
 instance Semigroup SideData where
-    SideData d f s w g h o l k c <> SideData d' f' s' w' g' h' o' l' k' c' =
-        SideData (d <> d') (f <> f') (s <> s') (w <> w') (g <> g') (h <> h') (o <> o') (l <> l') (k <> k') (c <> c')
+    SideData d f s w g h o l k c r <> SideData d' f' s' w' g' h' o' l' k' c' r' =
+        SideData (d <> d') (f <> f') (s <> s') (w <> w') (g <> g') (h <> h') (o <> o') (l <> l') (k <> k') (c <> c') (r <> r')
 
 instance Monoid SideData where
-    mempty = SideData mempty mempty mempty mempty mempty mempty mempty mempty mempty mempty
+    mempty = SideData mempty mempty mempty mempty mempty mempty mempty mempty mempty mempty mempty
     mappend = (<>)
 
 -- | The @DISTINCT@ "clause".
@@ -1879,6 +1884,12 @@ data CommonTableExpressionKind
 data CommonTableExpressionClause =
     CommonTableExpressionClause CommonTableExpressionKind Ident (IdentInfo -> (TLB.Builder, [PersistValue]))
 
+data ReturningClause
+    = ReturningNothing  -- ^ The default, absent clause.
+    | ReturningStar     -- ^ @RETURNING *@
+    -- | ReturningExprs (NonEmpty (SqlExpr Returning))
+    -- ^ @output_expression [ [ AS ] output_name ] [, ...]@
+
 data SubQueryType
     = NormalSubQuery
     | LateralSubQuery
@@ -2117,6 +2128,16 @@ instance Monoid LockingClause where
     mempty = NoLockingClause
     mappend = (<>)
 
+instance Semigroup ReturningClause where
+  (<>) ReturningNothing x = x
+  (<>) x ReturningNothing = x
+  (<>) ReturningStar ReturningStar = ReturningStar
+--   (<>) _ _ = error "instance Semigroup FIXME"
+
+instance Monoid ReturningClause where
+  mempty = ReturningNothing
+  mappend = (<>)
+
 ----------------------------------------------------------------------
 
 -- | Identifier used for table names.
@@ -2981,7 +3002,8 @@ toRawSql mode (conn, firstIdentState) query =
                  orderByClauses
                  limitClause
                  lockingClause
-                 cteClause = sd
+                 cteClause
+                 returningClause = sd
         -- Pass the finalIdentState (containing all identifiers
         -- that were used) to the subsequent calls.  This ensures
         -- that no name clashes will occur on subqueries that may
@@ -2999,6 +3021,7 @@ toRawSql mode (conn, firstIdentState) query =
         , makeOrderBy    info orderByClauses
         , makeLimit      info limitClause
         , makeLocking    info lockingClause
+        , makeReturning  info returningClause ret
         ]
 
 
@@ -3073,6 +3096,7 @@ data Mode
     | DELETE
     | UPDATE
     | INSERT_INTO
+    | UPDATE_RETSTAR
 
 uncommas :: [TLB.Builder] -> TLB.Builder
 uncommas = intersperseB ", "
@@ -3124,6 +3148,7 @@ makeSelect info mode_ distinctClause ret = process mode_
             DELETE      -> plain "DELETE "
             UPDATE      -> plain "UPDATE "
             INSERT_INTO -> process SELECT
+            UPDATE_RETSTAR -> plain "UPDATE "
     selectKind =
         case distinctClause of
             DistinctAll      -> ("SELECT ", [])
@@ -3151,6 +3176,7 @@ makeFrom info mode fs = ret
     keyword =
         case mode of
             UPDATE -> id
+            UPDATE_RETSTAR -> id
             _      -> first ("\nFROM " <>)
 
     mk _     (FromStart i def) = base i def
@@ -3268,6 +3294,13 @@ makeLocking info (PostgresLockingClauses clauses) =
             plain v = (v,[])
 makeLocking _ NoLockingClause = mempty
 
+makeReturning :: SqlSelect a r
+              => IdentInfo -> ReturningClause -> a -> (TLB.Builder, [PersistValue])
+makeReturning _    ReturningNothing _ = mempty
+makeReturning info ReturningStar  ret = ("RETURNING ", []) <> sqlSelectCols info ret
+-- makeReturning info (ReturningExprs _) = undefined -- FIXME
+
+
 parens :: TLB.Builder -> TLB.Builder
 parens b = "(" <> (b <> ")")
 
diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 3011741b4..d5552f4ed 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -23,6 +23,7 @@ module Database.Esqueleto.PostgreSQL
     , chr
     , now_
     , random_
+    , updateReturningAll
     , upsert
     , upsertBy
     , insertSelectWithConflict
@@ -41,6 +42,7 @@ module Database.Esqueleto.PostgreSQL
 #if __GLASGOW_HASKELL__ < 804
 import Data.Semigroup
 #endif
+import Conduit (withAcquire)
 import Control.Arrow (first)
 import Control.Exception (throw)
 import Control.Monad (void)
@@ -477,3 +479,11 @@ forUpdateOf lockableEntities onLockedBehavior =
 forShareOf :: LockableEntity a => a -> OnLockedBehavior -> SqlQuery ()
 forShareOf lockableEntities onLockedBehavior =
   putLocking $ PostgresLockingClauses [PostgresLockingKind PostgresForShare (Just $ LockingOfClause lockableEntities) onLockedBehavior]
+
+updateReturningAll :: (MonadIO m, PersistEntity ent, SqlBackendCanWrite backend, backend ~ PersistEntityBackend ent)
+                   => (SqlExpr (Entity ent) -> SqlQuery (SqlExpr (Entity ent)))
+                   -> R.ReaderT backend m [Entity ent]
+updateReturningAll block = do
+  conn <- R.ask
+  conduit <- rawSelectSource UPDATE_RETSTAR (tellReturning ReturningStar >> from block)
+  liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index 9e144e2be..e1f11514c 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1056,6 +1056,17 @@ testUpsert =
       u3e <- EP.upsert u3 [OneUniqueName =. val "fifth"]
       liftIO $ entityVal u3e `shouldBe` u1{oneUniqueName="fifth"}
 
+testUpdateDeleteReturning :: SpecDb
+testUpdateDeleteReturning =
+  describe "UPDATE .. RETURNING *" $ do
+    itDb "Whole updated entity gets returned" $ do
+      [p1k, p2k, p3k, p4k, p5k] <- mapM insert [p1, p2, p3, p4, p5]
+      ret <- EP.updateReturningAll $ \p -> do
+        set p [ PersonFavNum =. val 42 ]
+        where_ (p ^. PersonFavNum ==. val 4)
+        return p
+      asserting $ ret `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
+
 testInsertSelectWithConflict :: SpecDb
 testInsertSelectWithConflict =
   describe "insertSelectWithConflict test" $ do
@@ -1629,6 +1640,7 @@ spec = beforeAll mkConnectionPool $ do
         testPostgresqlTextFunctions
         testInsertUniqueViolation
         testUpsert
+        testUpdateDeleteReturning
         testInsertSelectWithConflict
         testFilterWhere
         testCommonTableExpressions

From 48d71be1707536ba8e62f7819fd6ef78c4ca404f Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Tue, 9 May 2023 17:06:57 +0200
Subject: [PATCH 02/15] cleanup: deduplicate extensions, fix trivial lints

* TypeOperators -- enabled twice on lines 3, 23
* TypeApplications -- enabled twice on lines 4, 21
* DerivingStrategies -- enabled twice on lines 5, 9
* GeneralizedNewtypeDeriving -- enabled twice on lines 5, 15

* MultiParamTypeClasses -- implied by FunctionalDependencies

This reduces lints from hlint & compiler warnings.
---
 src/Database/Esqueleto/Internal/Internal.hs | 16 ++++++----------
 src/Database/Esqueleto/PostgreSQL.hs        |  2 +-
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index 497f15fe9..ed2125cdd 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -1,8 +1,5 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE TypeApplications #-}
-{-# language DerivingStrategies, GeneralizedNewtypeDeriving #-}
 
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE DeriveDataTypeable #-}
@@ -14,7 +11,6 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE InstanceSigs #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE Rank2Types #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -669,7 +665,7 @@ isNothing v =
                         first (parensM p) . isNullExpr $ f Never info
   where
     isNullExpr :: (TLB.Builder, a) -> (TLB.Builder, a)
-    isNullExpr = first ((<> " IS NULL"))
+    isNullExpr = first (<> " IS NULL")
 
 -- | An alias for 'isNothing' that avoids clashing with the function from
 -- "Data.Maybe" 'Data.Maybe.isNothing'.
@@ -2445,7 +2441,7 @@ unsafeSqlCase when v = ERaw noMeta buildCase
         in ( b0 <> " WHEN " <> b1 <> " THEN " <> b2, vals0 <> vals1 <> vals2 )
 
     valueToSql :: SqlExpr (Value a) -> NeedParens -> IdentInfo -> (TLB.Builder, [PersistValue])
-    valueToSql (ERaw _ f) p = f p
+    valueToSql (ERaw _ f) = f
 
 -- | (Internal) Create a custom binary operator.  You /should/
 -- /not/ use this function directly since its type is very
@@ -2929,7 +2925,7 @@ deleteCount
     :: (MonadIO m, SqlBackendCanWrite backend)
     => SqlQuery ()
     -> R.ReaderT backend m Int64
-deleteCount a = rawEsqueleto DELETE a
+deleteCount = rawEsqueleto DELETE
 
 -- | Execute an @esqueleto@ @UPDATE@ query inside @persistent@'s
 -- 'SqlPersistT' monad.  Note that currently there are no type
@@ -3970,14 +3966,14 @@ insertSelect
     :: (MonadIO m, PersistEntity a, SqlBackendCanWrite backend)
     => SqlQuery (SqlExpr (Insertion a))
     -> R.ReaderT backend m ()
-insertSelect a = void $ insertSelectCount a
+insertSelect = void . insertSelectCount
 
 -- | Insert a 'PersistField' for every selected value, return the count afterward
 insertSelectCount
     :: (MonadIO m, PersistEntity a, SqlBackendCanWrite backend)
     => SqlQuery (SqlExpr (Insertion a))
     -> R.ReaderT backend m Int64
-insertSelectCount a = rawEsqueleto INSERT_INTO a
+insertSelectCount = rawEsqueleto INSERT_INTO
 
 -- | Renders an expression into 'Text'. Only useful for creating a textual
 -- representation of the clauses passed to an "On" clause.
@@ -3987,7 +3983,7 @@ renderExpr :: SqlBackend -> SqlExpr (Value Bool) -> T.Text
 renderExpr sqlBackend e = case e of
     ERaw _ mkBuilderValues ->
          let (builder, _) = mkBuilderValues Never (sqlBackend, initialIdentState)
-         in (builderToText builder)
+         in builderToText builder
 
 -- | An exception thrown by 'RenderExpr' - it's not designed to handle composite
 -- keys, and will blow up if you give it one.
diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index d5552f4ed..714e6ba46 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -77,7 +77,7 @@ maybeArray ::
      (PersistField a, PersistField [a])
   => SqlExpr (Value (Maybe [a]))
   -> SqlExpr (Value [a])
-maybeArray x = coalesceDefault [x] (emptyArray)
+maybeArray x = coalesceDefault [x] emptyArray
 
 -- | Aggregate mode
 data AggMode

From 9788cbbea8edd428adaa2d8d017e86be743e6d80 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Fri, 1 Sep 2023 14:17:14 +0200
Subject: [PATCH 03/15] cleanup: fix syntax of sub_select deprecation notice

https://downloads.haskell.org/ghc/latest/docs/users_guide/exts/pragmas.html#warning-and-deprecated-pragmas
---
 src/Database/Esqueleto/Internal/Internal.hs | 28 ++++++++++-----------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index ed2125cdd..a0c7475f1 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -427,21 +427,19 @@ putLocking clause = Q $ W.tell mempty { sdLockingClause = clause }
 tellReturning :: ReturningClause -> SqlQuery ()
 tellReturning clause = Q $ W.tell mempty { sdReturningClause = clause }
 
-{-#
-  DEPRECATED
-    sub_select
-    "sub_select \n \
-sub_select is an unsafe function to use. If used with a SqlQuery that \n \
-returns 0 results, then it may return NULL despite not mentioning Maybe \n \
-in the return type. If it returns more than 1 result, then it will throw a \n \
-SQL error.\n\n Instead, consider using one of the following alternatives: \n \
-- subSelect: attaches a LIMIT 1 and the Maybe return type, totally safe.  \n \
-- subSelectMaybe: Attaches a LIMIT 1, useful for a query that already \n \
-  has a Maybe in the return type. \n \
-- subSelectCount: Performs a count of the query - this is always safe. \n \
-- subSelectUnsafe: Performs no checks or guarantees. Safe to use with \n \
-  countRows and friends."
-  #-}
+{-# DEPRECATED sub_select
+  [ "sub_select is an unsafe function to use. If used with a SqlQuery that"
+  , "returns 0 results, then it may return NULL despite not mentioning Maybe"
+  , "in the return type. If it returns more than 1 result, then it will throw a"
+  , "SQL error.\n\n Instead, consider using one of the following alternatives:"
+  , "- subSelect: attaches a LIMIT 1 and the Maybe return type, totally safe. "
+  , "- subSelectMaybe: Attaches a LIMIT 1, useful for a query that already"
+  , "  has a Maybe in the return type."
+  , "- subSelectCount: Performs a count of the query - this is always safe."
+  , "- subSelectUnsafe: Performs no checks or guarantees. Safe to use with"
+  , "  countRows and friends."
+  ]
+#-}
 -- | Execute a subquery @SELECT@ in an SqlExpression.  Returns a
 -- simple value so should be used only when the @SELECT@ query
 -- is guaranteed to return just one row.

From c97d455f0539e48e69ca51b90cbec38449e67d26 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Wed, 10 May 2023 08:37:02 +0200
Subject: [PATCH 04/15] docs: haddock typos

---
 src/Database/Esqueleto/Internal/Internal.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index a0c7475f1..6a409e011 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -2084,10 +2084,10 @@ instance Monoid GroupByClause where
   mempty = GroupBy []
   mappend = (<>)
 
--- | A @HAVING@ cause.
+-- | A @HAVING@ clause.
 type HavingClause = WhereClause
 
--- | A @ORDER BY@ clause.
+-- | An @ORDER BY@ clause.
 type OrderByClause = SqlExpr OrderBy
 
 -- | A @LIMIT@ clause.

From c0044f73b115b9b3163dbcfab4fe29b46ce94546 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 12:17:29 +0200
Subject: [PATCH 05/15] feat: generalize, add InferReturning, add test

---
 src/Database/Esqueleto/Internal/Internal.hs | 33 +++++++++++++++++++++
 src/Database/Esqueleto/PostgreSQL.hs        |  6 ++--
 test/PostgreSQL/Test.hs                     | 15 +++++++---
 3 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index 6a409e011..f24fe0b93 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -2415,6 +2415,39 @@ existsHelper = sub SELECT . (>> return true)
     true  :: SqlExpr (Value Bool)
     true = val True
 
+-- | (Internal) The types which can appear in @RETURNING@ part of @UPDATE@ or @DELETE@
+--
+-- Many constructs appearing in @SELECT@ can go under @RETURNING@ -- but not all (e.g.
+-- certainly not subqueries, @VALUES@ and such). Thus, this is a subclass of 'SqlSelect'.
+class SqlSelect a r => InferReturning a r
+instance PersistEntity ent => InferReturning (SqlExpr (Entity ent)) (Entity ent)
+instance PersistEntity ent => InferReturning (SqlExpr (Maybe (Entity ent))) (Maybe (Entity ent))
+instance PersistField a => InferReturning (SqlExpr (Value a)) (Value a)
+instance ( InferReturning a ra, InferReturning b rb) => InferReturning (a, b) (ra, rb)
+instance ( InferReturning a ra
+         , InferReturning b rb
+         , InferReturning c rc
+         ) => InferReturning (a, b, c) (ra, rb, rc)
+instance ( InferReturning a ra
+         , InferReturning b rb
+         , InferReturning c rc
+         , InferReturning d rd
+         ) => InferReturning (a, b, c, d) (ra, rb, rc, rd)
+instance ( InferReturning a ra
+         , InferReturning b rb
+         , InferReturning c rc
+         , InferReturning d rd
+         , InferReturning e re
+         ) => InferReturning (a, b, c, d, e) (ra, rb, rc, rd, re)
+instance ( InferReturning a ra
+         , InferReturning b rb
+         , InferReturning c rc
+         , InferReturning d rd
+         , InferReturning e re
+         , InferReturning f rf
+         ) => InferReturning (a, b, c, d, e, f) (ra, rb, rc, rd, re, rf)
+-- tuple nesting provides unlimited arity if 6-tuple isn't enough
+
 -- | (Internal) Create a case statement.
 --
 -- Since: 2.1.1
diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 714e6ba46..8593229ed 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -480,9 +480,9 @@ forShareOf :: LockableEntity a => a -> OnLockedBehavior -> SqlQuery ()
 forShareOf lockableEntities onLockedBehavior =
   putLocking $ PostgresLockingClauses [PostgresLockingKind PostgresForShare (Just $ LockingOfClause lockableEntities) onLockedBehavior]
 
-updateReturningAll :: (MonadIO m, PersistEntity ent, SqlBackendCanWrite backend, backend ~ PersistEntityBackend ent)
-                   => (SqlExpr (Entity ent) -> SqlQuery (SqlExpr (Entity ent)))
-                   -> R.ReaderT backend m [Entity ent]
+updateReturningAll :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
+                   => (from -> SqlQuery ex)
+                   -> R.ReaderT backend m [ret]
 updateReturningAll block = do
   conn <- R.ask
   conduit <- rawSelectSource UPDATE_RETSTAR (tellReturning ReturningStar >> from block)
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index e1f11514c..e15ccddaf 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1059,13 +1059,20 @@ testUpsert =
 testUpdateDeleteReturning :: SpecDb
 testUpdateDeleteReturning =
   describe "UPDATE .. RETURNING *" $ do
-    itDb "Whole updated entity gets returned" $ do
-      [p1k, p2k, p3k, p4k, p5k] <- mapM insert [p1, p2, p3, p4, p5]
-      ret <- EP.updateReturningAll $ \p -> do
+    itDb "Whole entities, expressions and tuples get returned" $ do
+      [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
+      ret1 <- EP.updateReturningAll $ \p -> do
         set p [ PersonFavNum =. val 42 ]
         where_ (p ^. PersonFavNum ==. val 4)
         return p
-      asserting $ ret `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
+      asserting $ ret1 `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
+
+      ret2 <- EP.updateReturningAll $ \p -> do
+        set p [ PersonAge =. val (Just 0) ]
+        where_ (isNothing $ p ^. PersonAge)
+        return (val True, p ^. PersonName, (p ^. PersonFavNum) *. val 100)
+      asserting $ ret2 `shouldBe` [ (Value True, Value "Rachel", Value 200)
+                                  , (Value True, Value "Mitch", Value 500) ]
 
 testInsertSelectWithConflict :: SpecDb
 testInsertSelectWithConflict =

From b055b2e8277b2505c5b821733e0487a0b7a70743 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 12:35:48 +0200
Subject: [PATCH 06/15] feat: rename updateReturningAll -> updateReturning, add
 doc

---
 src/Database/Esqueleto/PostgreSQL.hs | 26 +++++++++++++++++++++-----
 test/PostgreSQL/Test.hs              |  4 ++--
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 8593229ed..7961b15be 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -23,7 +23,7 @@ module Database.Esqueleto.PostgreSQL
     , chr
     , now_
     , random_
-    , updateReturningAll
+    , updateReturning
     , upsert
     , upsertBy
     , insertSelectWithConflict
@@ -480,10 +480,26 @@ forShareOf :: LockableEntity a => a -> OnLockedBehavior -> SqlQuery ()
 forShareOf lockableEntities onLockedBehavior =
   putLocking $ PostgresLockingClauses [PostgresLockingKind PostgresForShare (Just $ LockingOfClause lockableEntities) onLockedBehavior]
 
-updateReturningAll :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
-                   => (from -> SqlQuery ex)
-                   -> R.ReaderT backend m [ret]
-updateReturningAll block = do
+-- | `UPDATE .. RETURNING ..` SQL extension supported by Postgres.
+--
+-- The instances of 'InferReturning' say what can be returned; currently includes
+-- whole entities, 'PersistField's, SQL expressions, tuples (possibly nested).
+--
+-- Usage example:
+--
+-- @
+--   tuples <- updateReturning $ \p -> do
+--     set p [ PersonAge =. val (Just 0) ]
+--     where_ (isNothing $ p ^. PersonAge)
+--     return (val True, p ^. PersonName, (p ^. PersonFavNum) *. val 100)
+--     -- return p -- also works, returning (Entity Person)
+-- @
+--
+-- @since 3.5.9.1
+updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
+                => (from -> SqlQuery ex)
+                -> R.ReaderT backend m [ret]
+updateReturning block = do
   conn <- R.ask
   conduit <- rawSelectSource UPDATE_RETSTAR (tellReturning ReturningStar >> from block)
   liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index e15ccddaf..3a916c2ae 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1061,13 +1061,13 @@ testUpdateDeleteReturning =
   describe "UPDATE .. RETURNING *" $ do
     itDb "Whole entities, expressions and tuples get returned" $ do
       [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
-      ret1 <- EP.updateReturningAll $ \p -> do
+      ret1 <- EP.updateReturning $ \p -> do
         set p [ PersonFavNum =. val 42 ]
         where_ (p ^. PersonFavNum ==. val 4)
         return p
       asserting $ ret1 `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
 
-      ret2 <- EP.updateReturningAll $ \p -> do
+      ret2 <- EP.updateReturning $ \p -> do
         set p [ PersonAge =. val (Just 0) ]
         where_ (isNothing $ p ^. PersonAge)
         return (val True, p ^. PersonName, (p ^. PersonFavNum) *. val 100)

From 63132c02fbe1d85b3e7acda48f945bdf7ff27122 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 12:41:28 +0200
Subject: [PATCH 07/15] feat: undo addition of UPDATE_RETSTAR, not necessary

---
 src/Database/Esqueleto/Internal/Internal.hs | 3 ---
 src/Database/Esqueleto/PostgreSQL.hs        | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index f24fe0b93..f31ec29c4 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -3123,7 +3123,6 @@ data Mode
     | DELETE
     | UPDATE
     | INSERT_INTO
-    | UPDATE_RETSTAR
 
 uncommas :: [TLB.Builder] -> TLB.Builder
 uncommas = intersperseB ", "
@@ -3175,7 +3174,6 @@ makeSelect info mode_ distinctClause ret = process mode_
             DELETE      -> plain "DELETE "
             UPDATE      -> plain "UPDATE "
             INSERT_INTO -> process SELECT
-            UPDATE_RETSTAR -> plain "UPDATE "
     selectKind =
         case distinctClause of
             DistinctAll      -> ("SELECT ", [])
@@ -3203,7 +3201,6 @@ makeFrom info mode fs = ret
     keyword =
         case mode of
             UPDATE -> id
-            UPDATE_RETSTAR -> id
             _      -> first ("\nFROM " <>)
 
     mk _     (FromStart i def) = base i def
diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 7961b15be..31f9b7562 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -501,5 +501,5 @@ updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWr
                 -> R.ReaderT backend m [ret]
 updateReturning block = do
   conn <- R.ask
-  conduit <- rawSelectSource UPDATE_RETSTAR (tellReturning ReturningStar >> from block)
+  conduit <- rawSelectSource UPDATE (tellReturning ReturningStar >> from block)
   liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource

From e9fa6814940f0cc5edf7eb4b102176e21e55e723 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 13:09:53 +0200
Subject: [PATCH 08/15] feat: improve error messages

---
 src/Database/Esqueleto/Internal/Internal.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index f31ec29c4..600c38f99 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -2419,7 +2419,7 @@ existsHelper = sub SELECT . (>> return true)
 --
 -- Many constructs appearing in @SELECT@ can go under @RETURNING@ -- but not all (e.g.
 -- certainly not subqueries, @VALUES@ and such). Thus, this is a subclass of 'SqlSelect'.
-class SqlSelect a r => InferReturning a r
+class SqlSelect a r => InferReturning a r | r -> a, a -> r
 instance PersistEntity ent => InferReturning (SqlExpr (Entity ent)) (Entity ent)
 instance PersistEntity ent => InferReturning (SqlExpr (Maybe (Entity ent))) (Maybe (Entity ent))
 instance PersistField a => InferReturning (SqlExpr (Value a)) (Value a)

From afee7b0f03e57b3d2d96893d24b5b8981e1e281d Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 13:26:04 +0200
Subject: [PATCH 09/15] feat: add deleteReturning and test

---
 src/Database/Esqueleto/PostgreSQL.hs | 23 +++++++++++++++++++++++
 test/PostgreSQL/Test.hs              | 16 +++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 31f9b7562..5f076cffa 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -23,6 +23,7 @@ module Database.Esqueleto.PostgreSQL
     , chr
     , now_
     , random_
+    , deleteReturning
     , updateReturning
     , upsert
     , upsertBy
@@ -503,3 +504,25 @@ updateReturning block = do
   conn <- R.ask
   conduit <- rawSelectSource UPDATE (tellReturning ReturningStar >> from block)
   liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
+
+-- | `DELETE .. RETURNING` SQL extension supported by Postgres.
+--
+-- The instances of 'InferReturning' say what can be returned; currently includes
+-- whole entities, 'PersistField's, SQL expressions, tuples (possibly nested).
+--
+-- Usage example:
+--
+-- @
+--   removedRowsWithNames <- deleteReturning $ \p -> do
+--     where_ (isNothing $ p ^. PersonWeight)
+--     return (p, p ^. PersonName)
+-- @
+--
+-- @since 3.5.9.1
+deleteReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
+                => (from -> SqlQuery ex)
+                -> R.ReaderT backend m [ret]
+deleteReturning block = do
+  conn <- R.ask
+  conduit <- rawSelectSource DELETE (tellReturning ReturningStar >> from block)
+  liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index 3a916c2ae..52cb73682 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1059,7 +1059,7 @@ testUpsert =
 testUpdateDeleteReturning :: SpecDb
 testUpdateDeleteReturning =
   describe "UPDATE .. RETURNING *" $ do
-    itDb "Whole entities, expressions and tuples get returned" $ do
+    itDb "Whole entities, expressions and tuples get returned from UPDATE" $ do
       [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
       ret1 <- EP.updateReturning $ \p -> do
         set p [ PersonFavNum =. val 42 ]
@@ -1074,6 +1074,20 @@ testUpdateDeleteReturning =
       asserting $ ret2 `shouldBe` [ (Value True, Value "Rachel", Value 200)
                                   , (Value True, Value "Mitch", Value 500) ]
 
+    itDb "Whole entities, expressions and tuples get returned from DELETE" $ do
+      [_p1k, p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
+      ret1 <- EP.deleteReturning $ \p -> do
+        where_ (isNothing $ p ^. PersonWeight)
+        return (val (1 :: Int, 2 :: Int), p ^. PersonName, isNothing (p ^. PersonAge))
+      asserting $ ret1 `shouldBe` [ (Value (1, 2), Value "John", Value False)
+                                  , (Value (1, 2), Value "Mike", Value False)
+                                  , (Value (1, 2), Value "Mitch", Value True) ]
+      ret2 <- EP.deleteReturning $ \p -> do
+        -- empty WHERE -- delete everything remaining... but:
+        return (p, p ^. PersonName)
+      asserting $ ret2 `shouldBe` [ (Entity p2k p2, Value "Rachel")
+                                  , (Entity p4k p4, Value "Livia") ]
+
 testInsertSelectWithConflict :: SpecDb
 testInsertSelectWithConflict =
   describe "insertSelectWithConflict test" $ do

From b8204ac9d4b273f6e16c28de8f82a79c64e73c21 Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Thu, 11 May 2023 13:36:37 +0200
Subject: [PATCH 10/15] feat: PR prep cleanup

---
 changelog.md                                | 1 -
 src/Database/Esqueleto/Internal/Internal.hs | 9 ++++-----
 test/PostgreSQL/Test.hs                     | 2 +-
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/changelog.md b/changelog.md
index 1cf09376b..5df48e61c 100644
--- a/changelog.md
+++ b/changelog.md
@@ -53,7 +53,6 @@
     - [#363](https://github.com/bitemyapp/esqueleto/pull/363)
       - Add missing `just` to left join examples in the Haddocks
 
-
 3.5.9.0
 =======
 - @9999years
diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index 600c38f99..9f3c745e9 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -1880,9 +1880,7 @@ data CommonTableExpressionClause =
 
 data ReturningClause
     = ReturningNothing  -- ^ The default, absent clause.
-    | ReturningStar     -- ^ @RETURNING *@
-    -- | ReturningExprs (NonEmpty (SqlExpr Returning))
-    -- ^ @output_expression [ [ AS ] output_name ] [, ...]@
+    | ReturningStar     -- ^ @RETURNING@ is present.
 
 data SubQueryType
     = NormalSubQuery
@@ -2126,7 +2124,6 @@ instance Semigroup ReturningClause where
   (<>) ReturningNothing x = x
   (<>) x ReturningNothing = x
   (<>) ReturningStar ReturningStar = ReturningStar
---   (<>) _ _ = error "instance Semigroup FIXME"
 
 instance Monoid ReturningClause where
   mempty = ReturningNothing
@@ -2419,6 +2416,9 @@ existsHelper = sub SELECT . (>> return true)
 --
 -- Many constructs appearing in @SELECT@ can go under @RETURNING@ -- but not all (e.g.
 -- certainly not subqueries, @VALUES@ and such). Thus, this is a subclass of 'SqlSelect'.
+--
+-- The fundeps duplicate those of 'SqlSelect' solely to provide somewhat more directly
+-- understandable type errors.
 class SqlSelect a r => InferReturning a r | r -> a, a -> r
 instance PersistEntity ent => InferReturning (SqlExpr (Entity ent)) (Entity ent)
 instance PersistEntity ent => InferReturning (SqlExpr (Maybe (Entity ent))) (Maybe (Entity ent))
@@ -3322,7 +3322,6 @@ makeReturning :: SqlSelect a r
               => IdentInfo -> ReturningClause -> a -> (TLB.Builder, [PersistValue])
 makeReturning _    ReturningNothing _ = mempty
 makeReturning info ReturningStar  ret = ("RETURNING ", []) <> sqlSelectCols info ret
--- makeReturning info (ReturningExprs _) = undefined -- FIXME
 
 
 parens :: TLB.Builder -> TLB.Builder
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index 52cb73682..7759c68cc 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1058,7 +1058,7 @@ testUpsert =
 
 testUpdateDeleteReturning :: SpecDb
 testUpdateDeleteReturning =
-  describe "UPDATE .. RETURNING *" $ do
+  describe "UPDATE .. RETURNING .." $ do
     itDb "Whole entities, expressions and tuples get returned from UPDATE" $ do
       [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
       ret1 <- EP.updateReturning $ \p -> do

From 8ba4f3a52e817d53b5f5e1eaa2fe1f9f1b38b47b Mon Sep 17 00:00:00 2001
From: Max Ulidtko <ulidtko@gmail.com>
Date: Wed, 1 May 2024 10:31:27 +0200
Subject: [PATCH 11/15] docs: changelog

---
 changelog.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/changelog.md b/changelog.md
index 5df48e61c..13d2bb40f 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,9 @@
+3.5.11.3 (unreleased)
+========
+- @ulidtko
+    - [#362](https://github.com/bitemyapp/esqueleto/pull/362)
+      - Add `updateReturning`, `deleteReturning` as Postgres extensions.
+
 3.5.11.2
 ========
 - @arguri

From 2e29743b772e6e20b1863d34fd846895d80bfdaf Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Fri, 1 Sep 2023 14:24:42 +0200
Subject: [PATCH 12/15] Update @since haddoc tags, after upstream did 2
 releases while ignoring PR

---
 src/Database/Esqueleto/PostgreSQL.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 5f076cffa..eda3ae6c3 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -496,7 +496,7 @@ forShareOf lockableEntities onLockedBehavior =
 --     -- return p -- also works, returning (Entity Person)
 -- @
 --
--- @since 3.5.9.1
+-- @since 3.5.10.2
 updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]
@@ -518,7 +518,7 @@ updateReturning block = do
 --     return (p, p ^. PersonName)
 -- @
 --
--- @since 3.5.9.1
+-- @since 3.5.10.2
 deleteReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]

From 7a757897eb309ad195c203a70e26439f0eacc5fb Mon Sep 17 00:00:00 2001
From: max ulidtko <ulidtko@gmail.com>
Date: Fri, 1 Sep 2023 14:30:00 +0200
Subject: [PATCH 13/15] Update @since tags, after upstream released 3.5.10.2
 while ignoring PR

---
 src/Database/Esqueleto/PostgreSQL.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index eda3ae6c3..6af1d4974 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -496,7 +496,7 @@ forShareOf lockableEntities onLockedBehavior =
 --     -- return p -- also works, returning (Entity Person)
 -- @
 --
--- @since 3.5.10.2
+-- @since 3.5.10.3
 updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]
@@ -518,7 +518,7 @@ updateReturning block = do
 --     return (p, p ^. PersonName)
 -- @
 --
--- @since 3.5.10.2
+-- @since 3.5.10.3
 deleteReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]

From 564cb837a8c98cde02ea22a237b0f020d00da44b Mon Sep 17 00:00:00 2001
From: Max Ulidtko <ulidtko@gmail.com>
Date: Wed, 1 May 2024 10:33:04 +0200
Subject: [PATCH 14/15] Update @since haddoc tags, after upstream did 3
 releases while ignoring PR

---
 src/Database/Esqueleto/PostgreSQL.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 6af1d4974..87b79f3ab 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -496,7 +496,7 @@ forShareOf lockableEntities onLockedBehavior =
 --     -- return p -- also works, returning (Entity Person)
 -- @
 --
--- @since 3.5.10.3
+-- @since 3.5.11.3
 updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]
@@ -518,7 +518,7 @@ updateReturning block = do
 --     return (p, p ^. PersonName)
 -- @
 --
--- @since 3.5.10.3
+-- @since 3.5.11.3
 deleteReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWrite backend)
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]

From 1b93b6e3318d6a0b877585f9309b2acf3a7d5acd Mon Sep 17 00:00:00 2001
From: Max Ulidtko <ulidtko@gmail.com>
Date: Wed, 1 May 2024 17:04:11 +0200
Subject: [PATCH 15/15] fmt: indents and newlines

---
 src/Database/Esqueleto/Internal/Internal.hs | 18 ++++--
 src/Database/Esqueleto/PostgreSQL.hs        | 12 ++--
 test/PostgreSQL/Test.hs                     | 61 +++++++++++----------
 3 files changed, 51 insertions(+), 40 deletions(-)

diff --git a/src/Database/Esqueleto/Internal/Internal.hs b/src/Database/Esqueleto/Internal/Internal.hs
index 9f3c745e9..d72193ada 100644
--- a/src/Database/Esqueleto/Internal/Internal.hs
+++ b/src/Database/Esqueleto/Internal/Internal.hs
@@ -2121,13 +2121,13 @@ instance Monoid LockingClause where
     mappend = (<>)
 
 instance Semigroup ReturningClause where
-  (<>) ReturningNothing x = x
-  (<>) x ReturningNothing = x
-  (<>) ReturningStar ReturningStar = ReturningStar
+    (<>) ReturningNothing x = x
+    (<>) x ReturningNothing = x
+    (<>) ReturningStar ReturningStar = ReturningStar
 
 instance Monoid ReturningClause where
-  mempty = ReturningNothing
-  mappend = (<>)
+    mempty = ReturningNothing
+    mappend = (<>)
 
 ----------------------------------------------------------------------
 
@@ -2420,25 +2420,33 @@ existsHelper = sub SELECT . (>> return true)
 -- The fundeps duplicate those of 'SqlSelect' solely to provide somewhat more directly
 -- understandable type errors.
 class SqlSelect a r => InferReturning a r | r -> a, a -> r
+
 instance PersistEntity ent => InferReturning (SqlExpr (Entity ent)) (Entity ent)
+
 instance PersistEntity ent => InferReturning (SqlExpr (Maybe (Entity ent))) (Maybe (Entity ent))
+
 instance PersistField a => InferReturning (SqlExpr (Value a)) (Value a)
+
 instance ( InferReturning a ra, InferReturning b rb) => InferReturning (a, b) (ra, rb)
+
 instance ( InferReturning a ra
          , InferReturning b rb
          , InferReturning c rc
          ) => InferReturning (a, b, c) (ra, rb, rc)
+
 instance ( InferReturning a ra
          , InferReturning b rb
          , InferReturning c rc
          , InferReturning d rd
          ) => InferReturning (a, b, c, d) (ra, rb, rc, rd)
+
 instance ( InferReturning a ra
          , InferReturning b rb
          , InferReturning c rc
          , InferReturning d rd
          , InferReturning e re
          ) => InferReturning (a, b, c, d, e) (ra, rb, rc, rd, re)
+
 instance ( InferReturning a ra
          , InferReturning b rb
          , InferReturning c rc
diff --git a/src/Database/Esqueleto/PostgreSQL.hs b/src/Database/Esqueleto/PostgreSQL.hs
index 87b79f3ab..1f8685c31 100644
--- a/src/Database/Esqueleto/PostgreSQL.hs
+++ b/src/Database/Esqueleto/PostgreSQL.hs
@@ -501,9 +501,9 @@ updateReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWr
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]
 updateReturning block = do
-  conn <- R.ask
-  conduit <- rawSelectSource UPDATE (tellReturning ReturningStar >> from block)
-  liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
+    conn <- R.ask
+    conduit <- rawSelectSource UPDATE (tellReturning ReturningStar >> from block)
+    liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
 
 -- | `DELETE .. RETURNING` SQL extension supported by Postgres.
 --
@@ -523,6 +523,6 @@ deleteReturning :: (MonadIO m, From from, InferReturning ex ret, SqlBackendCanWr
                 => (from -> SqlQuery ex)
                 -> R.ReaderT backend m [ret]
 deleteReturning block = do
-  conn <- R.ask
-  conduit <- rawSelectSource DELETE (tellReturning ReturningStar >> from block)
-  liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
+    conn <- R.ask
+    conduit <- rawSelectSource DELETE (tellReturning ReturningStar >> from block)
+    liftIO . withAcquire conduit $ flip R.runReaderT conn . runSource
diff --git a/test/PostgreSQL/Test.hs b/test/PostgreSQL/Test.hs
index 7759c68cc..ef38a1c74 100644
--- a/test/PostgreSQL/Test.hs
+++ b/test/PostgreSQL/Test.hs
@@ -1058,35 +1058,38 @@ testUpsert =
 
 testUpdateDeleteReturning :: SpecDb
 testUpdateDeleteReturning =
-  describe "UPDATE .. RETURNING .." $ do
-    itDb "Whole entities, expressions and tuples get returned from UPDATE" $ do
-      [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
-      ret1 <- EP.updateReturning $ \p -> do
-        set p [ PersonFavNum =. val 42 ]
-        where_ (p ^. PersonFavNum ==. val 4)
-        return p
-      asserting $ ret1 `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
-
-      ret2 <- EP.updateReturning $ \p -> do
-        set p [ PersonAge =. val (Just 0) ]
-        where_ (isNothing $ p ^. PersonAge)
-        return (val True, p ^. PersonName, (p ^. PersonFavNum) *. val 100)
-      asserting $ ret2 `shouldBe` [ (Value True, Value "Rachel", Value 200)
-                                  , (Value True, Value "Mitch", Value 500) ]
-
-    itDb "Whole entities, expressions and tuples get returned from DELETE" $ do
-      [_p1k, p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
-      ret1 <- EP.deleteReturning $ \p -> do
-        where_ (isNothing $ p ^. PersonWeight)
-        return (val (1 :: Int, 2 :: Int), p ^. PersonName, isNothing (p ^. PersonAge))
-      asserting $ ret1 `shouldBe` [ (Value (1, 2), Value "John", Value False)
-                                  , (Value (1, 2), Value "Mike", Value False)
-                                  , (Value (1, 2), Value "Mitch", Value True) ]
-      ret2 <- EP.deleteReturning $ \p -> do
-        -- empty WHERE -- delete everything remaining... but:
-        return (p, p ^. PersonName)
-      asserting $ ret2 `shouldBe` [ (Entity p2k p2, Value "Rachel")
-                                  , (Entity p4k p4, Value "Livia") ]
+    describe "UPDATE .. RETURNING .." $ do
+        itDb "Whole entities, expressions and tuples get returned from UPDATE" $ do
+            [_p1k, _p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
+            ret1 <- EP.updateReturning $ \p -> do
+                set p [ PersonFavNum =. val 42 ]
+                where_ (p ^. PersonFavNum ==. val 4)
+                return p
+            asserting $ ret1 `shouldBe` [Entity p4k p4{ personFavNum = 42 }]
+
+            ret2 <- EP.updateReturning $ \p -> do
+                set p [ PersonAge =. val (Just 0) ]
+                where_ (isNothing $ p ^. PersonAge)
+                return (val True, p ^. PersonName, (p ^. PersonFavNum) *. val 100)
+            asserting $ ret2 `shouldBe` [ (Value True, Value "Rachel", Value 200)
+                                        , (Value True, Value "Mitch", Value 500) ]
+
+        itDb "Whole entities, expressions and tuples get returned from DELETE" $ do
+            [_p1k, p2k, _p3k, p4k, _p5k] <- mapM insert [p1, p2, p3, p4, p5]
+            ret1 <- EP.deleteReturning $ \p -> do
+                where_ (isNothing $ p ^. PersonWeight)
+                return ( val (1 :: Int, 2 :: Int)
+                       , p ^. PersonName
+                       , isNothing (p ^. PersonAge)
+                       )
+            asserting $ ret1 `shouldBe` [ (Value (1, 2), Value "John", Value False)
+                                        , (Value (1, 2), Value "Mike", Value False)
+                                        , (Value (1, 2), Value "Mitch", Value True) ]
+            ret2 <- EP.deleteReturning $ \p -> do
+                -- empty WHERE -- delete everything remaining... but:
+                return (p, p ^. PersonName)
+            asserting $ ret2 `shouldBe` [ (Entity p2k p2, Value "Rachel")
+                                        , (Entity p4k p4, Value "Livia") ]
 
 testInsertSelectWithConflict :: SpecDb
 testInsertSelectWithConflict =