(WIP) fix: spread embeds failing with count() aggregate

- Fixed "column reference <col> is ambiguous" when selecting "?select=...table(col,count())"
- Fixed "column <json_aggregate>.<alias> does not exist" when selecting "?select=...table(aias:count())"

src/PostgREST/Plan.hs

@@ -53,6 +53,7 @@ import PostgREST.SchemaCache.Identifiers     (FieldName,
                                               QualifiedIdentifier (..),
                                               RelIdentifier (..),
                                               Schema)
+                                              --TableName)
 import PostgREST.SchemaCache.Relationship    (Cardinality (..),
                                               Junction (..),
                                               Relationship (..),
@@ -270,7 +271,7 @@ data ResolverContext = ResolverContext
   }
 
 resolveColumnField :: Column -> CoercibleField
-resolveColumnField col = CoercibleField (colName col) mempty False (colNominalType col) Nothing (colDefault col)
+resolveColumnField col = CoercibleField (colName col) mempty False (colNominalType col) Nothing (colDefault col) False
 
 resolveTableFieldName :: Table -> FieldName -> CoercibleField
 resolveTableFieldName table fieldName =
@@ -376,15 +377,24 @@ initReadRequest ctx@ResolverContext{qi=QualifiedIdentifier{..}} =
 addAliases :: ReadPlanTree -> Either ApiRequestError ReadPlanTree
 addAliases = Right . fmap addAliasToPlan
   where
-    addAliasToPlan rp@ReadPlan{select=sel} = rp{select=map aliasSelectField sel}
+    addAliasToPlan rp@ReadPlan{select=sel, relIsSpread=spr} = rp{select=map (aliasSelectField spr) sel}
 
-    aliasSelectField :: CoercibleSelectField -> CoercibleSelectField
-    aliasSelectField field@CoercibleSelectField{csField=fieldDetails, csAggFunction=aggFun, csAlias=alias}
-      | isJust alias || isJust aggFun = field
+    aliasSelectField :: Bool -> CoercibleSelectField -> CoercibleSelectField
+    aliasSelectField isSpread field@CoercibleSelectField{csField=fieldDetails, csAggFunction=aggFun, csAlias=alias}
+      | isJust alias = field
+      | isJust aggFun = fieldAliasForSpreadAgg isSpread field
       | isJsonKeyPath fieldDetails, Just key <- lastJsonKey fieldDetails = field { csAlias = Just key }
       | isTransformPath fieldDetails = field { csAlias = Just (cfName fieldDetails) }
       | otherwise = field
 
+    fieldAliasForSpreadAgg isSpread field@CoercibleSelectField{csField=fieldDetails, csAggFunction=aggFun} =
+      -- A request like: `/top_table?select=...middle_table(...nested_table(count()))` will `SELECT` the full row instead of `*`,
+      -- because doing a `COUNT(*)` in `top_table` would not return the desired results.
+      -- So we use the "count" alias if none is present since the field name won't be selected.
+      if isSpread && cfName fieldDetails == "*" && aggFun == Just Count
+      then field { csAlias = Just "count" }
+      else field
+
     isJsonKeyPath CoercibleField{cfJsonPath=(_: _)} = True
     isJsonKeyPath _                                 = False
 
@@ -703,9 +713,10 @@ hoistFromSelectFields relAggAlias fields =
       let (modifiedField, maybeAgg) = modifyField field
       in (modifiedField : newFields, maybeAgg : aggList)
 
-    modifyField field@CoercibleSelectField{csAggFunction=Just aggFunc, csField, csAggCast, csAlias} =
-      let determineFieldName = fromMaybe (cfName csField) csAlias
-          updatedField = field {csAggFunction = Nothing, csAggCast = Nothing}
+    modifyField field@CoercibleSelectField{csAggFunction=Just aggFunc, csField=fieldDetails, csAggCast, csAlias} =
+      let determineFieldName = fromMaybe (cfName fieldDetails) csAlias
+          isFullRow = cfName fieldDetails == "*" && aggFunc == Count
+          updatedField = field {csField = fieldDetails{cfFullRow = isFullRow}, csAggFunction = Nothing, csAggCast = Nothing}
           hoistedField = Just ((relAggAlias, determineFieldName), (aggFunc, csAggCast, csAlias))
       in (updatedField, hoistedField)
     modifyField field = (field, Nothing)
@@ -858,7 +869,7 @@ addNullEmbedFilters (Node rp@ReadPlan{where_=curLogic} forest) = do
     newNullFilters rPlans = \case
       (CoercibleExpr b lOp trees) ->
         CoercibleExpr b lOp <$> (newNullFilters rPlans `traverse` trees)
-      flt@(CoercibleStmnt (CoercibleFilter (CoercibleField fld [] _ _ _ _) opExpr)) ->
+      flt@(CoercibleStmnt (CoercibleFilter (CoercibleField fld [] _ _ _ _ _) opExpr)) ->
         let foundRP = find (\ReadPlan{relName, relAlias} -> fld == fromMaybe relName relAlias) rPlans in
         case (foundRP, opExpr) of
           (Just ReadPlan{relAggAlias}, OpExpr b (Is TriNull)) -> Right $ CoercibleStmnt $ CoercibleFilterNullEmbed b relAggAlias

src/PostgREST/Plan/Types.hs

@@ -39,10 +39,11 @@ data CoercibleField = CoercibleField
   , cfIRType    :: Text                  -- ^ The native Postgres type of the field, the intermediate (IR) type before mapping.
   , cfTransform :: Maybe TransformerProc -- ^ The optional mapping from irType -> targetType.
   , cfDefault   :: Maybe Text
+  , cfFullRow   :: Bool                  -- ^ True if the field represents the whole selected row. Used in spread rels: instead of COUNT(*), it does a COUNT(<row>) in order to not mix with other spreaded resources.
   } deriving (Eq, Show)
 
 unknownField :: FieldName -> JsonPath -> CoercibleField
-unknownField name path = CoercibleField name path False "" Nothing Nothing
+unknownField name path = CoercibleField name path False "" Nothing Nothing False
 
 -- | Like an API request LogicTree, but with coercible field information.
 data CoercibleLogicTree

src/PostgREST/Query/QueryBuilder.hs

@@ -206,7 +206,7 @@ callPlanToQuery (FunctionCall qi params arguments returnsScalar returnsSetOfScal
       KeyParams []    -> "FROM " <> callIt mempty
       KeyParams prms  -> case arguments of
         DirectArgs args -> "FROM " <> callIt (fmtArgs prms args)
-        JsonArgs json   -> fromJsonBodyF json ((\p -> CoercibleField (ppName p) mempty False (ppTypeMaxLength p) Nothing Nothing) <$> prms) False True False <> ", " <>
+        JsonArgs json   -> fromJsonBodyF json ((\p -> CoercibleField (ppName p) mempty False (ppTypeMaxLength p) Nothing Nothing False) <$> prms) False True False <> ", " <>
                          "LATERAL " <> callIt (fmtParams prms)
 
     callIt :: SQL.Snippet -> SQL.Snippet

src/PostgREST/Query/SqlFragment.hs

@@ -252,6 +252,7 @@ pgFmtCallUnary :: Text -> SQL.Snippet -> SQL.Snippet
 pgFmtCallUnary f x = SQL.sql (encodeUtf8 f) <> "(" <> x <> ")"
 
 pgFmtField :: QualifiedIdentifier -> CoercibleField -> SQL.Snippet
+pgFmtField table CoercibleField{cfFullRow=True}                                          = fromQi table
 pgFmtField table CoercibleField{cfName=fn, cfJsonPath=[]}                                = pgFmtColumn table fn
 pgFmtField table CoercibleField{cfName=fn, cfToJson=doToJson, cfJsonPath=jp} | doToJson  = "to_jsonb(" <> pgFmtColumn table fn <> ")" <> pgFmtJsonPath jp
                                                                              | otherwise = pgFmtColumn table fn <> pgFmtJsonPath jp

test/spec/fixtures/data.sql

@@ -895,11 +895,13 @@ INSERT INTO process_categories VALUES (1, 'Batch');
 INSERT INTO process_categories VALUES (2, 'Mass');
 
 TRUNCATE TABLE processes CASCADE;
-INSERT INTO processes VALUES (1, 'Process A1', 1, 1);
-INSERT INTO processes VALUES (2, 'Process A2', 1, 2);
-INSERT INTO processes VALUES (3, 'Process B1', 2, 1);
-INSERT INTO processes VALUES (4, 'Process B2', 2, 1);
-INSERT INTO processes VALUES (5, 'Process C1', 3, 2);
+INSERT INTO processes VALUES (1, 'Process A1', 23, 1, 1);
+INSERT INTO processes VALUES (2, 'Process A2', 23, 1, 2);
+INSERT INTO processes VALUES (3, 'Process B1', 23, 2, 1);
+INSERT INTO processes VALUES (4, 'Process B2', 23, 2, 1);
+INSERT INTO processes VALUES (5, 'Process C1', 23, 3, 2);
+INSERT INTO processes VALUES (6, 'Process C2', 23, 3, 2);
+INSERT INTO processes VALUES (7, 'Process XX', 23, 3, 2);
 
 TRUNCATE TABLE process_costs CASCADE;
 INSERT INTO process_costs VALUES (1, 150.00);
@@ -922,3 +924,4 @@ INSERT INTO process_supervisor VALUES (3, 4);
 INSERT INTO process_supervisor VALUES (4, 1);
 INSERT INTO process_supervisor VALUES (4, 2);
 INSERT INTO process_supervisor VALUES (5, 3);
+INSERT INTO process_supervisor VALUES (6, 3);

test/spec/fixtures/schema.sql

@@ -3763,6 +3763,7 @@ create table process_categories (
 create table processes (
   id int primary key,
   name text,
+  count int,
   factory_id int references factories(id),
   category_id int references process_categories(id)
 );