fix: filter on unselected columns in a table-valued function

src/PostgREST/Plan.hs

@@ -1019,6 +1019,7 @@ callPlan proc ApiRequest{} paramKeys args readReq = FunctionCall {
 , funCScalar = funcReturnsScalar proc
 , funCSetOfScalar = funcReturnsSetOfScalar proc
 , funCRetCompositeAlias = funcReturnsCompositeAlias proc
+, funCFilterFields = getFilterFieldNames readReq
 , funCReturning = inferColsEmbedNeeds readReq []
 }
   where
@@ -1028,6 +1029,22 @@ callPlan proc ApiRequest{} paramKeys args readReq = FunctionCall {
             | otherwise            -> KeyParams $ specifiedParams [prm]
       prms  -> KeyParams $ specifiedParams prms
 
+-- | Get filter fields/column names from read plan
+getFilterFieldNames :: ReadPlanTree -> Set FieldName
+getFilterFieldNames rpt = S.fromList $ foldr (\rp names -> names <> rpToFieldNames rp) [] rpt
+  where
+    rpToFieldNames :: ReadPlan -> [FieldName]
+    rpToFieldNames = logicTreesToFieldName . ReadPlan.where_
+
+    logicTreesToFieldName :: [CoercibleLogicTree] -> [FieldName]
+    logicTreesToFieldName = concatMap coLogicTreeToFieldNames
+
+    coLogicTreeToFieldNames :: CoercibleLogicTree -> [FieldName]
+    coLogicTreeToFieldNames = \case
+      CoercibleStmnt (CoercibleFilter{field=CoercibleField{cfName}}) -> [cfName]
+      CoercibleStmnt (CoercibleFilterNullEmbed _ cfName) -> [cfName] -- needs test coverage
+      CoercibleExpr _ _ clts -> concatMap coLogicTreeToFieldNames clts
+
 -- | Infers the columns needed for an embed to be successful after a mutation or a function call.
 inferColsEmbedNeeds :: ReadPlanTree -> [FieldName] -> S.Set FieldName
 inferColsEmbedNeeds (Node ReadPlan{select} forest) pkCols

src/PostgREST/Plan/CallPlan.hs

@@ -25,6 +25,7 @@ data CallPlan = FunctionCall
   , funCScalar            :: Bool
   , funCSetOfScalar       :: Bool
   , funCRetCompositeAlias :: Bool
+  , funCFilterFields      :: Set FieldName
   , funCReturning         :: Set FieldName
   }
 

src/PostgREST/Query/QueryBuilder.hs

@@ -170,7 +170,7 @@ mutatePlanToQuery (Delete mainQi logicForest returnings) =
     whereLogic = if null logicForest then mempty else " WHERE " <> intercalateSnippet " AND " (pgFmtLogicTree mainQi <$> logicForest)
 
 callPlanToQuery :: CallPlan -> PgVersion -> SQL.Snippet
-callPlanToQuery (FunctionCall qi params arguments returnsScalar returnsSetOfScalar returnsCompositeAlias returnings) pgVer =
+callPlanToQuery (FunctionCall qi params arguments returnsScalar returnsSetOfScalar returnsCompositeAlias filterFields returnings) pgVer =
   "SELECT " <> (if returnsScalar || returnsSetOfScalar then "pgrst_call.pgrst_scalar" else returnedColumns) <> " " <>
   fromCall
   where
@@ -211,10 +211,16 @@ callPlanToQuery (FunctionCall qi params arguments returnsScalar returnsSetOfScal
         -- We could fallback to providing this NULL value in those cases.
         encodeArg Nothing = "NULL"
 
+    -- the columns here would be the returnings + the columns that would later
+    -- be used by a where clause filter, if they intersect, we remove the duplicates
+    -- and if * is returned then no need to explicitly add filter columns
     returnedColumns :: SQL.Snippet
-    returnedColumns
-      | null returnings = "*"
-      | otherwise       = intercalateSnippet ", " (pgFmtColumn (QualifiedIdentifier mempty "pgrst_call") <$> S.toList returnings)
+    returnedColumns = case S.toList returnings of
+      []    -> "*"
+      ["*"] -> pgFmtColumn (QualifiedIdentifier mempty "pgrst_call") "*"
+      _     -> intercalateSnippet ", " (pgFmtColumn (QualifiedIdentifier mempty "pgrst_call") <$> returnedColumns')
+        where
+          returnedColumns' = S.toList $ returnings <> filterFields
 
 -- | SQL query meant for COUNTing the root node of the Tree.
 -- It only takes WHERE into account and doesn't include LIMIT/OFFSET because it would reduce the COUNT.