Support filters over 1:N connections

graphql/accessor_general.lua

@@ -902,20 +902,22 @@ local function process_tuple(self, state, tuple, opts)
     end
 
     -- make subrequests if needed
+    local truncated_filter = table.copy(filter)
     for k, v in pairs(filter) do
         if obj[k] == nil then
             local field_name = k
             local sub_filter = v
-            local field = resolveField(field_name, obj, sub_filter)
+            local field, is_list = resolveField(field_name, obj, sub_filter)
             if field == nil then return true end
-            obj[k] = field
-            -- XXX: Remove the value from a filter? But then we need to copy
-            -- the filter each time in the case.
+            if is_list then
+                if next(field) == nil then return true end
+            end
+            truncated_filter[k] = nil
         end
     end
 
     -- filter out non-matching objects
-    local match = utils.is_subtable(obj, filter) and
+    local match = utils.is_subtable(obj, truncated_filter) and
         match_using_re(obj, pcre)
     if do_filter then
         if not match then return true end
@@ -1570,7 +1572,7 @@ end
 ---   - `qcontext` (table) can be used by an accessor to store any
 ---     query-related data;
 ---   - `resolveField(field_name, object, filter, opts)` (function) for
----     performing a subrequest on a fields connected using a 1:1 connection.
+---     performing a subrequest on a fields connected using a connection.
 ---   - extra_args
 ---   - exp_tuple_count
 function accessor_general.new(opts, funcs)

graphql/convert_schema/resolve.lua

@@ -123,8 +123,13 @@ function resolve.gen_resolve_function(collection_name, connection,
                 c.destination_collection))
             local opts = table.copy(opts or {})
             opts.is_hidden = true
-            return bare_destination_type.fields[field_name].resolve(
-                object, filter, info, opts)
+            local result, field_type =
+                bare_destination_type.fields[field_name].resolve(object,
+                filter, info, opts)
+            local field_type = field_type or
+                bare_destination_type.fields[field_name].kind
+            local is_list = core_types.nullable(field_type).__type == 'List'
+            return result, is_list
         end
     end
 

graphql/convert_schema/schema.lua

@@ -161,7 +161,7 @@ local function for_each_connection(state, connection_types, func)
     end
 end
 
---- Add arguments corresponding to 1:1 connections (nested filters).
+--- Add arguments corresponding to connections (nested filters).
 ---
 --- @tparam table state graphql_tarantool instance
 local function add_connection_arguments(state)
@@ -170,8 +170,8 @@ local function add_connection_arguments(state)
     -- map source collection and connection name to an input object
     local lookup_input_objects = {}
 
-    -- create InputObjects for each 1:1 connection of each collection
-    for_each_connection(state, {'1:1'}, function(collection_name, c)
+    -- create InputObjects for each connection of each collection
+    for_each_connection(state, {'1:1', '1:N'}, function(collection_name, c)
         -- XXX: support multihead connections
         if c.variants ~= nil then return end
 
@@ -196,7 +196,7 @@ local function add_connection_arguments(state)
 
     -- update fields of collection arguments and input objects with other input
     -- objects
-    for_each_connection(state, {'1:1'}, function(collection_name, c)
+    for_each_connection(state, {'1:1', '1:N'}, function(collection_name, c)
         -- XXX: support multihead connections
         if c.variants ~= nil then return end