fix(postgrest): make new function inference mostly retro compatible

Author: avallete

packages/core/postgrest-js/src/types.ts

@@ -40,7 +40,14 @@ export type GetRpcFunctionFilterBuilderByArgs<
       : // Otherwise, we attempt to match with one of the function definition in the union based
         // on the function arguments provided
         Args extends GenericFunction['Args']
-        ? LastOf<FindMatchingFunctionByArgs<Schema['Functions'][FnName], Args>>
+        ? // This is for retro compatibility, if the funcition is defined with an single return and an union of Args
+          // we fallback to the last function definition matched by name
+          IsNever<
+            LastOf<FindMatchingFunctionByArgs<Schema['Functions'][FnName], Args>>
+          > extends true
+          ? LastOf<Schema['Functions'][FnName]>
+          : // Otherwise, we use the arguments based function definition narrowing to get the right value
+            LastOf<FindMatchingFunctionByArgs<Schema['Functions'][FnName], Args>>
         : // If we can't find a matching function by args, we try to find one by function name
           ExtractExactFunction<Schema['Functions'][FnName], Args> extends GenericFunction
           ? ExtractExactFunction<Schema['Functions'][FnName], Args>