[Tarantool-patches] [PATCH luajit] test: adapt test checking tail calls debug info

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

LuaJIT does not provide information about tail calls,
unlike Lua does. getfenv() behavior for this test set is also different in
LuaJIT, because tail calls do not provide additional call frame.

Closes tarantool/tarantool#5702
Part of tarantool/tarantool#5845
Part of tarantool/tarantool#4473
---
GitHub branch: https://github.com/tarantool/luajit/tree/fckxorg/gh-5702-adapt-getfenv-getinfo-PUC-Rio
Issue: https://github.com/tarantool/tarantool/issues/5702
See also https://luajit.org/status.html

 test/PUC-Rio-Lua-5.1-tests/db.lua | 61 +++++++++++++------------------
 1 file changed, 26 insertions(+), 35 deletions(-)

diff --git a/test/PUC-Rio-Lua-5.1-tests/db.lua b/test/PUC-Rio-Lua-5.1-tests/db.lua
index 56f59ea8..a94f07ab 100644
--- a/test/PUC-Rio-Lua-5.1-tests/db.lua
+++ b/test/PUC-Rio-Lua-5.1-tests/db.lua
@@ -378,21 +378,22 @@ if jit_is_enabled then
   jit.on()
 end
 
-
 -- tests for tail calls
+-- LuaJIT does not provide information about tail calls,
+-- unlike Lua does. See also https://luajit.org/status.html.
+-- getfenv() behavior is also different here, because tail calls
+-- do not provide additional call frame for LuaJIT.
+-- See also https://github.com/tarantool/tarantool/issues/5702.
+-- This function is adapted to LuaJIT behavior.
 local function f (x)
   if x then
     assert(debug.getinfo(1, "S").what == "Lua")
     local tail = debug.getinfo(2)
-    assert(not pcall(getfenv, 3))
-    assert(tail.what == "tail" and tail.short_src == "(tail call)" and
-           tail.linedefined == -1 and tail.func == nil)
-    assert(debug.getinfo(3, "f").func == g1)
+    assert(pcall(getfenv, 3))
+    assert(tail.what == "Lua" and tail.linedefined == 403 and tail.func == g1)
+    -- End of single assert
     assert(getfenv(3))
-    assert(debug.getinfo(4, "S").what == "tail")
-    assert(not pcall(getfenv, 5))
-    assert(debug.getinfo(5, "S").what == "main")
-    assert(getfenv(5))
+    assert(debug.getinfo(3, "S").what == "main")
     print"+"
     end
 end
@@ -403,43 +404,33 @@ function g1(x) g(x) end
 
 local function h (x) local f=g1; return f(x) end
 
--- FIXME: LuaJIT does not provide information about tail calls,
--- unlike Lua does. See also https://luajit.org/status.html.
--- getfenv() behaviour is also different here, because tail calls
--- do not provide additional call frame for LuaJIT and level
--- number should be changed.
--- Test is disabled for LuaJIT.
--- See also https://github.com/tarantool/tarantool/issues/5702.
--- h(true)
+-- This fucntions is adapted to LuaJIT behavior. See the comment above.
+h(true)
 
 local b = {}
--- FIXME: Behavior is different for LuaJIT. See the comment above.
--- Test is disabled for LuaJIT.
--- debug.sethook(function (e) table.insert(b, e) end, "cr")
--- h(false)
--- debug.sethook()
-local res = {"return",   -- first return (from sethook)
-  "call", "call", "call", "call",
-  "return", "tail return", "return", "tail return",
-  "call",    -- last call (to sethook)
+debug.sethook(function (e) table.insert(b, e) end, "cr")
+-- This fucntions is adapted to LuaJIT behavior. See the comment above.
+h(false)
+debug.sethook()
+-- This chunk is adapted to LuaJIT behavior. See the comment above.
+local res = {"call",   -- first return (from sethook)
+  "call", "call", "call", "return",
+  "return", "call"
 }
--- FIXME: Behavior is different for LuaJIT. See the comment above.
--- Test is disabled for LuaJIT.
--- for _, k in ipairs(res) do assert(k == table.remove(b, 1)) end
+for _, k in ipairs(res) do assert(k == table.remove(b, 1)) end
 
 
-lim = 30000
+-- This chunk is adapted to LuaJIT behavior. See the comment above.
+lim = 2
 local function foo (x)
   if x==0 then
-    assert(debug.getinfo(lim+2).what == "main")
-    for i=2,lim do assert(debug.getinfo(i, "S").what == "tail") end
+    assert(debug.getinfo(lim + 1,"S").what == "main")
+    assert(debug.getinfo(lim, "S").what == "main")
   else return foo(x-1)
   end
 end
 
--- FIXME: Behavior is different for LuaJIT.
--- See the comment to `h()` above. Test is disabled for LuaJIT.
--- foo(lim)
+foo(lim)
 
 
 print"+"
-- 
2.33.0