app-luattest/http_client_test.lua fails after Lua JIT update

[locker]

Only the master (3.0) branch seems to be affected. I couldn't reproduce the issue on 2.11 or 2.10.

After commit cde911d was pushed, app-luatest/http_client_test.lua started to fail on CI with the following errors:

    http_client.sock_family:"AF_INET".test_encode_body_method_post_default_content_type_number ... (5.705s) fail
...arantool/tarantool/test/app-luatest/http_client_test.lua:55: connection is ok
expected: 200, actual: 595
    http_client.sock_family:"AF_INET".test_encode_body_method_post_default_content_type_boolean ... (5.198s) fail
...arantool/tarantool/test/app-luatest/http_client_test.lua:55: connection is ok
expected: 200, actual: 595
    http_client.sock_family:"AF_INET".test_body_decoders ... (5.127s) fail
...arantool/tarantool/test/app-luatest/http_client_test.lua:55: connection is ok
expected: 200, actual: 595
    http_client.sock_family:"AF_INET".test_default_body_decoders ... (5.096s) fail
...arantool/tarantool/test/app-luatest/http_client_test.lua:55: connection is ok
expected: 200, actual: 595

The issue can be reproduced locally with (it fails quite often but not always so you might need to run it a few times):

luatest -v test/app-luatest/http_client_test.lua -r 10

Disabling Lua JIT in the test helps.

Patch disabling Lua JIT in the test

diff --git a/test/app-luatest/http_client_test.lua b/test/app-luatest/http_client_test.lua
index b45cc9cc21f5..86f8a102a925 100644
--- a/test/app-luatest/http_client_test.lua
+++ b/test/app-luatest/http_client_test.lua
@@ -5,6 +5,9 @@ local uri = require('uri')
 local os = require('os')
 local t = require('luatest')
 
+jit.off()
+jit.flush()
+
 local g = t.group('http_client', {
     {sock_family = 'AF_INET'},
     {sock_family = 'AF_UNIX'},

NOTE: We disabled Lua JIT in the test in commit 53c94bc. Please roll it back as soon as the bug is fixed.

If you apply the following patch to the test you'll get a more verbose failure log:

Patch making the test more verbose

diff --git a/test/app-luatest/http_client_test.lua b/test/app-luatest/http_client_test.lua
index b45cc9cc21f5..45143420bf74 100644
--- a/test/app-luatest/http_client_test.lua
+++ b/test/app-luatest/http_client_test.lua
@@ -52,7 +52,7 @@ local function start_server(sock_family)
     t.helpers.retrying({}, function()
         local ok, res = pcall(client.get, url, client_opts)
         t.skip_if(not ok, "not supported")
-        t.assert_equals(res.status, 200, "connection is ok")
+        t.assert_covers(res, {status = 200}, "connection is ok")
     end)
 
     return server, url, client_opts

    http_client.sock_family:"AF_INET".test_errors ... (5.753s) fail
...arantool/tarantool/test/app-luatest/http_client_test.lua:55: connection is ok
expected
{
    _decoders = {
        ["application/json"] = function: 0x41323be0,
        ["application/msgpack"] = function: 0x41323c20,
        ["application/yaml"] = function: 0x41323c00,
    },
    reason = "Couldn't resolve host name",
    status = 595,
    url = 5.782961770405e-313,
} to cover
{status = 200}

Note that the url contains a number but it shouldn't be possible because it's initialized with a string:

tarantool/test/app-luatest/http_client_test.lua

Lines 50 to 56 in 2afde5b

	url = string.format("http://%s/", sock_addr)
	t.helpers.retrying({}, function()
	local ok, res = pcall(client.get, url, client_opts)
	t.skip_if(not ok, "not supported")
	t.assert_equals(res.status, 200, "connection is ok")
	end)

[Buristan]

Should be fixed via backporting of 2801500a ("Fix use-def analysis for BC_VARG."). I've added this commit to the backport list in #8516. JIT compilation should be enabled after the aforementioned commit is backported.