From 213f1941bfa3be7d73994aeb2795c138a4964249 Mon Sep 17 00:00:00 2001
From: Jarvis <jarvis@api7.ai>
Date: Wed, 20 May 2026 12:38:36 +0800
Subject: [PATCH 1/3] fix: mark decoded arrays with cjson array metatable

---
 lib/resty/simdjson/decoder.lua |  3 ++-
 t/02-decode.t                  | 15 +++++++++---
 t/09-empty_array.t             | 42 ++++++++++++++++++++++++++++++++--
 3 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/lib/resty/simdjson/decoder.lua b/lib/resty/simdjson/decoder.lua
index 774ed88..2f12899 100644
--- a/lib/resty/simdjson/decoder.lua
+++ b/lib/resty/simdjson/decoder.lua
@@ -5,6 +5,7 @@ local _MT = { __index = _M, }
 local ffi = require("ffi")
 local table_new = require("table.new")
 local C = require("resty.simdjson.cdefs")
+local cjson_array_mt = require("cjson").array_mt
 
 
 local type = type
@@ -110,7 +111,7 @@ function _M:_build_array(count)
 
     local err
     local n = 1
-    local tbl = table_new(count, 0)
+    local tbl = setmetatable(table_new(count, 0), cjson_array_mt)
     local ops = self.ops
     local yieldable = self.yieldable
 
diff --git a/t/02-decode.t b/t/02-decode.t
index 14ac484..1e0af63 100644
--- a/t/02-decode.t
+++ b/t/02-decode.t
@@ -159,6 +159,7 @@ ok
 --- config
     location = /t {
         content_by_lua_block {
+            local cjson = require("cjson")
             local simdjson = require("resty.simdjson")
 
             local parser = simdjson.new()
@@ -166,19 +167,28 @@ ok
 
             local v = parser:decode("[1, 2, 3]")
             assert(type(v) == "table")
+            assert(getmetatable(v) == cjson.array_mt)
             assert(#v == 3)
             assert(v[1] == 1 and v[2] == 2 and v[3] == 3)
 
             local v = parser:decode("[true, 2, \"abc\"]")
             assert(type(v) == "table")
+            assert(getmetatable(v) == cjson.array_mt)
             assert(#v == 3)
             assert(v[1] == true and v[2] == 2 and v[3] == "abc")
 
             local v = parser:decode("[1, null, 3]")
             assert(type(v) == "table")
+            assert(getmetatable(v) == cjson.array_mt)
             assert(#v == 3)
             assert(v[1] == 1 and v[2] == ngx.null and v[3] == 3)
 
+            local v = parser:decode("[[1], []]")
+            assert(type(v) == "table")
+            assert(getmetatable(v) == cjson.array_mt)
+            assert(getmetatable(v[1]) == cjson.array_mt)
+            assert(getmetatable(v[2]) == cjson.array_mt)
+
             ngx.say("ok")
         }
     }
@@ -198,6 +208,7 @@ ok
 --- config
     location = /t {
         content_by_lua_block {
+            local cjson = require("cjson")
             local simdjson = require("resty.simdjson")
 
             local parser = simdjson.new()
@@ -205,6 +216,7 @@ ok
 
             local v = parser:decode([[{"a":1, "b":true, "c":"string"}]])
             assert(type(v) == "table")
+            assert(getmetatable(v) ~= cjson.array_mt)
             assert(v.a == 1 and v.b == true and v.c == "string")
 
             local v = parser:decode([[{"a":1.0, "b":null, "c":false}]])
@@ -459,6 +471,3 @@ simdjson: error: STRING_ERROR: Problem while parsing a string
 [error]
 [warn]
 [crit]
-
-
-
diff --git a/t/09-empty_array.t b/t/09-empty_array.t
index f79e1af..f4f4513 100644
--- a/t/09-empty_array.t
+++ b/t/09-empty_array.t
@@ -54,6 +54,46 @@ ok
 
 
 
+=== TEST 4: cjson encode decoded empty array
+--- http_config eval: $::HttpConfig
+--- config
+    location = /t {
+        content_by_lua_block {
+            local cjson = require("cjson")
+            local simdjson = require("resty.simdjson")
+
+            local parser = simdjson.new()
+            assert(parser)
+
+            local v = parser:decode("[]")
+            assert(type(v) == "table")
+            assert(getmetatable(v) == cjson.array_mt)
+            assert(cjson.encode(v) == "[]")
+
+            local v = parser:decode([[{"arr":[]}]])
+            assert(type(v) == "table")
+            assert(getmetatable(v.arr) == cjson.array_mt)
+            assert(cjson.encode(v) == [[{"arr":[]}]])
+
+            local v = parser:decode("{}")
+            assert(type(v) == "table")
+            assert(getmetatable(v) ~= cjson.array_mt)
+            assert(cjson.encode(v) == "{}")
+
+            ngx.say("ok")
+        }
+    }
+--- request
+GET /t
+--- response_body
+ok
+--- no_error_log
+[error]
+[warn]
+[crit]
+
+
+
 === TEST 2: cjson empty_array userdata
 --- http_config eval: $::HttpConfig
 --- config
@@ -111,5 +151,3 @@ ok
 [warn]
 [crit]
 
-
-

From 37908f37efc47b13ffb487af124cea36f9c57570 Mon Sep 17 00:00:00 2001
From: Jarvis <jarvis@api7.ai>
Date: Wed, 20 May 2026 12:44:05 +0800
Subject: [PATCH 2/3] test: keep empty array cases in order

---
 t/09-empty_array.t | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/t/09-empty_array.t b/t/09-empty_array.t
index f4f4513..3c868fd 100644
--- a/t/09-empty_array.t
+++ b/t/09-empty_array.t
@@ -54,7 +54,7 @@ ok
 
 
 
-=== TEST 4: cjson encode decoded empty array
+=== TEST 2: cjson encode decoded empty array
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
@@ -94,7 +94,7 @@ ok
 
 
 
-=== TEST 2: cjson empty_array userdata
+=== TEST 3: cjson empty_array userdata
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
@@ -123,7 +123,7 @@ ok
 
 
 
-=== TEST 3: cjson empty_array_mt
+=== TEST 4: cjson empty_array_mt
 --- http_config eval: $::HttpConfig
 --- config
     location = /t {
@@ -150,4 +150,3 @@ ok
 [error]
 [warn]
 [crit]
-

From aa3816eb0a7d71cc04ebab6b9ce87cf722079a95 Mon Sep 17 00:00:00 2001
From: Jarvis <jarvis@api7.ai>
Date: Wed, 20 May 2026 12:50:46 +0800
Subject: [PATCH 3/3] ci: use ubuntu latest for tests

---
 .github/workflows/tests.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 79a37d7..c0328e3 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,7 +11,7 @@ concurrency:
 jobs:
   tests:
     name: Tests
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     strategy:
       matrix: