feat: validate ?columns mutation targets based on schema cache (#2542)

This returns an error for trying to update or insert into invalid columns, without hitting the database. This change also switches from `json_populate_recordset` for these operations `json_to_recordset` which should make no functional difference except allowing future flexibility.

src/PostgREST/Plan/MutatePlan.hs

@@ -4,20 +4,21 @@ module PostgREST.Plan.MutatePlan
 where
 
 import qualified Data.ByteString.Lazy as LBS
-import qualified Data.Set             as S
 
 import PostgREST.ApiRequest.Preferences  (PreferResolution)
 import PostgREST.ApiRequest.Types        (LogicTree, OrderTerm)
+import PostgREST.Plan.Types              (TypedField)
 import PostgREST.RangeQuery              (NonnegRange)
 import PostgREST.SchemaCache.Identifiers (FieldName,
                                           QualifiedIdentifier)
 
+
 import Protolude
 
 data MutatePlan
   = Insert
       { in_        :: QualifiedIdentifier
-      , insCols    :: S.Set FieldName
+      , insCols    :: [TypedField]
       , insBody    :: Maybe LBS.ByteString
       , onConflict :: Maybe (PreferResolution, [FieldName])
       , where_     :: [LogicTree]
@@ -26,7 +27,7 @@ data MutatePlan
       }
   | Update
       { in_       :: QualifiedIdentifier
-      , updCols   :: S.Set FieldName
+      , updCols   :: [TypedField]
       , updBody   :: Maybe LBS.ByteString
       , where_    :: [LogicTree]
       , mutRange  :: NonnegRange

src/PostgREST/Plan/Types.hs

@@ -0,0 +1,24 @@
+module PostgREST.Plan.Types
+  ( TypedField(..)
+  , resolveTableField
+
+  ) where
+
+import qualified Data.HashMap.Strict.InsOrd as HMI
+
+import PostgREST.SchemaCache.Identifiers (FieldName)
+import PostgREST.SchemaCache.Table       (Column (..), Table (..))
+
+import Protolude
+
+-- | A TypedField is a field with sufficient information to be read from JSON with `json_to_recordset`.
+data TypedField = TypedField
+   { tfName   :: FieldName
+   , tfIRType :: Text -- ^ The initial type of the field, before any casting.
+   } deriving (Eq)
+
+resolveTableField :: Table -> FieldName -> Maybe TypedField
+resolveTableField table fieldName =
+  case HMI.lookup fieldName (tableColumns table) of
+    Just column -> Just $ TypedField (colName column) (colNominalType column)
+    Nothing     -> Nothing