lyaml: fix alias serialization

The tarantool#8350 was introduced by the commit b42302f ("lua-yaml: enable
aliasing for objects returned by __serialize") so the patch is
effectively reversed.

The idea is to call all object __serialize methods recursively before
finding references. In the process we need to keep an eye on reference
structure of course.

Closes tarantool#8350
Closes tarantool#8321
Closes tarantool#8310

NO_DOC=bugfix

changelogs/unreleased/fix-yaml-alias-serialization.md

@@ -0,0 +1,3 @@
+## bugfix/lua
+
+* Fixed yaml alias serialization (gh-8350, gh-8321, gh-8310).

src/lua/serializer.c

@@ -329,7 +329,6 @@ lua_field_try_serialize(struct lua_State *L, struct luaL_serializer *cfg,
 		if (luaL_tofield(L, cfg, -1, field) != 0)
 			return -1;
 		lua_replace(L, idx);
-		field->serialized = true;
 		return 0;
 	}
 	if (!lua_isstring(L, -1)) {
@@ -441,7 +440,6 @@ luaL_tofield(struct lua_State *L, struct luaL_serializer *cfg, int index,
 	field->type = MP_NIL;
 	field->ext_type = MP_UNKNOWN_EXTENSION;
 	field->compact = false;
-	field->serialized = false;
 
 	if (index < 0)
 		index = lua_gettop(L) + index + 1;

src/lua/serializer.h

@@ -241,8 +241,6 @@ struct luaL_field {
 	/* subtypes of MP_EXT */
 	enum mp_extension_type ext_type;
 	bool compact;                /* a flag used by YAML serializer */
-	/** Set if __serialize metamethod was called for this field. */
-	bool serialized;
 };
 
 /**

test/app-luatest/serializer_test.lua

@@ -0,0 +1,42 @@
+local yaml = require('yaml')
+local fiber = require('fiber')
+local t = require('luatest')
+
+local g = t.group()
+
+local strip = function(str)
+    return str:gsub('^%s*', ''):gsub('\n%s*', '\n')
+end
+
+local function serialize(o)
+    return yaml.decode(yaml.encode(o))
+end
+
+g.test_gh_8350_no_unnecessary_anchors = function()
+    local x = {{}}
+    setmetatable(x, {__serialize = function(t) return {x[1]} end})
+    local expected = [[
+        ---
+        - []
+        ...
+    ]]
+    t.assert_equals(yaml.encode(x), strip(expected))
+end
+
+g.test_gh_8310_alias_across_serialize_method = function()
+    local x = {}
+    local y = setmetatable({}, {__serialize = function() return x end})
+    local z = {x, y}
+    local expected = [[
+        ---
+        - &0 []
+        - *0
+        ...
+    ]]
+    t.assert_equals(yaml.encode(z), strip(expected))
+end
+
+g.test_gh_8321_alias_between_same_udata_objects = function()
+    local x = serialize({fiber.self(), fiber.self()})
+    t.assert(x[1] == x[2])
+end

test/app-tap/tap.result

@@ -145,16 +145,16 @@ not ok - failed subtests
     not ok - {1} and {2}
       ---
       path: //1
-      strict: false
-      expected: 2
       got: 1
+      expected: 2
+      strict: false
       ...
     not ok - {1,2,{3,4}} and {1,2,{3,5}}
       ---
       path: //3/2
-      strict: false
-      expected: 5
       got: 4
+      expected: 5
+      strict: false
       ...
     ok - {} and {a = box.NULL} strict = false
     ok - {a = box.NULL} and {} strict = false
@@ -165,57 +165,57 @@ not ok - failed subtests
     ok - {a = box.NULL} and {a = box.NULL} strict false
     not ok - {} and {a = box.NULL} strict = true
       ---
-      strict: true
-      expected: key a
       got: nil
+      expected: key a
+      strict: true
       ...
     not ok - {a = box.NULL} and {} strict = true
       ---
       path: //a
-      strict: true
-      expected: nil
       got: cdata
+      expected: nil
+      strict: true
       ...
     not ok - {a = box.NULL} and {b = box.NULL} strict = true
       ---
       path: //a
-      strict: true
-      expected: nil
       got: cdata
+      expected: nil
+      strict: true
       ...
     not ok - {a = box.NULL} and {b = box.NULL, c = box.NULL} strict = true
       ---
       path: //a
-      strict: true
-      expected: nil
       got: cdata
+      expected: nil
+      strict: true
       ...
     not ok - nil and box.NULL strict = true
       ---
-      got: nil
-      expected: cdata
       strict: true
+      expected: cdata
+      got: nil
       ...
     not ok - box.NULL and nil strict = true
       ---
-      got: cdata
-      expected: nil
       strict: true
+      expected: nil
+      got: cdata
       ...
     ok - {a = box.NULL} and {a = box.NULL} strict true
         # check strict flag inheritance
         1..2
         not ok - {} and {a = box.NULL} strict = true
           ---
-          strict: true
-          expected: key a
           got: nil
+          expected: key a
+          strict: true
           ...
         not ok - nil and box.NULL strict = true
           ---
-          got: nil
-          expected: cdata
           strict: true
+          expected: cdata
+          got: nil
           ...
         # check strict flag inheritance: end
     not ok - failed subtests
@@ -237,20 +237,20 @@ not ok - failed subtests
 ok - like
 not ok - compare {1, 2, 3} and '200'
   ---
-  strict: false
-  expected: '200'
   got:
   - 1
   - 2
   - 3
+  expected: '200'
+  strict: false
   ...
 not ok - compare '200' and {1, 2, 3}
   ---
-  strict: false
+  got: '200'
   expected:
   - 1
   - 2
   - 3
-  got: '200'
+  strict: false
   ...
 # failed subtest: 21

test/app/argparse.result

@@ -75,11 +75,11 @@ argparse({'tarantoolctl', 'start', 'instance', '-vovov'})
 - 1: tarantoolctl
   2: start
   3: instance
-  o:
+  v:
   - true
   - true
-  v:
   - true
+  o:
   - true
   - true
 ...

test/box/alter.result

@@ -717,8 +717,8 @@ s.index.pk
   hint: true
   id: 0
   type: TREE
-  space_id: 512
   name: pk
+  space_id: 512
 ...
 s:select{}
 ---
@@ -750,8 +750,8 @@ s.index.pk
   hint: true
   id: 0
   type: TREE
-  space_id: 512
   name: pk
+  space_id: 512
 ...
 s.index.secondary
 ---
@@ -765,8 +765,8 @@ s.index.secondary
   hint: true
   id: 1
   type: TREE
-  space_id: 512
   name: secondary
+  space_id: 512
 ...
 s.index.secondary:select{}
 ---

test/box/errinj.result

@@ -1732,21 +1732,21 @@ rtreespace:create_index('pk', {if_not_exists = true})
   hint: true
   id: 0
   type: TREE
-  space_id: 512
   name: pk
+  space_id: 512
 ...
 rtreespace:create_index('target', {type='rtree', dimension = 3, parts={2, 'array'},unique = false, if_not_exists = true,})
 ---
 - parts:
   - type: array
     exclude_null: false
-    is_nullable: false
     fieldno: 2
-  dimension: 3
+    is_nullable: false
   id: 1
   type: RTREE
   space_id: 512
   name: target
+  dimension: 3
 ...
 count = 10
 ---

test/box/function1.result

@@ -99,8 +99,8 @@ box.func["function1.args"]
   id: 66
   takes_raw_args: false
   setuid: false
-  is_multikey: false
   is_deterministic: false
+  is_multikey: false
   name: function1.args
   language: C
 ...
@@ -587,8 +587,8 @@ func
   id: 66
   takes_raw_args: false
   setuid: false
-  is_multikey: false
   is_deterministic: false
+  is_multikey: false
   comment: Divide two values
   name: divide
   language: LUA
@@ -660,8 +660,8 @@ func
   id: 66
   takes_raw_args: false
   setuid: false
-  is_multikey: false
   is_deterministic: false
+  is_multikey: false
   name: function1.divide
   language: C
 ...

test/box/gh-5451-netbox-path-index-schema.result

@@ -28,26 +28,26 @@ c = netbox.connect(box.cfg.listen)
 c.space.gh5451.index[0].parts
 ---
 - - fieldno: 1
-    path: path1
     type: unsigned
     exclude_null: false
     is_nullable: false
+    path: path1
 ...
 c.space.gh5451.index[1].parts
 ---
 - - fieldno: 2
-    path: path2
     type: unsigned
     exclude_null: false
     is_nullable: false
+    path: path2
 ...
 c.space.gh5451.index[2].parts
 ---
 - - fieldno: 3
-    path: '[*]'
     type: unsigned
     exclude_null: false
     is_nullable: false
+    path: '[*]'
 ...
 c:close()
 ---

test/box/gh-5998-one-tx-for-ddl.result

@@ -47,8 +47,8 @@ s1:create_index('pk')
  |   hint: true
  |   id: 0
  |   type: TREE
- |   space_id: 512
  |   name: pk
+ |   space_id: 512
  | ...
 
 for i = 0, 10 do s1:replace{i} end

test/box/net.box_fiber-async_gh-3107.result

@@ -277,8 +277,8 @@ tostring(future)
 ...
 future
 ---
-- xyz: abc
-  abc: 123
+- abc: 123
+  xyz: abc
 ...
 future:wait_result()
 ---