Fix overloading of functions with unnamed arguments (specifically for prefer params=single-object)

CHANGELOG.md

@@ -25,6 +25,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #1585, Fix error messages on connection failure for localized postgres on Windows - @wolfgangwalther
  - #1636, Fix `application/octet-stream` appending `charset=utf-8` - @steve-chavez
  - #1615, Fix RPC return type handling and embedding for domains with composite base type - @wolfgangwalther
+ - #1469, Fix overloading of functions with unnamed arguments - @wolfgangwalther
 
 ### Changed
 

src/PostgREST/DbStructure.hs

@@ -153,6 +153,7 @@ decodeProcs =
     parseArgs :: Text -> [PgArg]
     parseArgs = mapMaybe parseArg . filter (not . isPrefixOf "OUT" . toS) . map strip . split (==',')
 
+    -- TODO: does parseArg properly handle unnamed "character varying" arguments or arguments with spaces in their names?
     parseArg :: Text -> Maybe PgArg
     parseArg arg =
       let isVariadic = isPrefixOf "VARIADIC " $ toS arg
@@ -161,7 +162,9 @@ decodeProcs =
           (body, def) = breakOn " DEFAULT " argNoMode
           (name, typ) = breakOn " " body in
       if T.null typ
-         then Nothing
+         -- Handle unnamed args. TODO: refactor to types
+         then Just $
+           PgArg mempty (strip name) (T.null def) isVariadic
          else Just $
            PgArg (dropAround (== '"') name) (strip typ) (T.null def) isVariadic
 

test/Feature/RpcSpec.hs

@@ -284,6 +284,19 @@ spec actualPgVersion =
           [json|null|]
           { matchHeaders = [matchContentTypeJson] }
 
+      context "different types when overloaded" $ do
+        it "returns composite type" $
+          post "/rpc/ret_point_overloaded" [json|{"x": 1, "y": 2}|] `shouldRespondWith`
+            [json|[{"x": 1, "y": 2}]|]
+            { matchHeaders = [matchContentTypeJson] }
+
+        it "returns json scalar with prefer single object" $
+          request methodPost "/rpc/ret_point_overloaded" [("Prefer","params=single-object")]
+            [json|{"x": 1, "y": 2}|]
+            `shouldRespondWith`
+            [json|{"x": 1, "y": 2}|]
+            { matchHeaders = [matchContentTypeJson] }
+
     context "proc argument types" $ do
       -- different syntax for array needed for pg<10
       when (actualPgVersion < pgVersion100) $

test/fixtures/schema.sql

@@ -983,6 +983,14 @@ create function test.ret_point_2d() returns test.point_2d as $$
   select row(10, 5)::test.point_2d;
 $$ language sql;
 
+create function test.ret_point_overloaded(x int, y int) returns test.point_2d as $$
+  select row(x, y)::test.point_2d;
+$$ language sql;
+
+create function test.ret_point_overloaded(json) returns json as $$
+  select $1;
+$$ language sql;
+
 -- domains on composite types are only supported from pg 11 on
 do $do$begin
   if (SELECT current_setting('server_version_num')::int >= 110000) then