Re: [Tarantool-patches] [PATCH luajit] test: adapt tests checking debug line hook trace

[Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi, Maxim!

Thanks for the patch!

Please consider my comments below.

On 24.09.21, Maxim Kokryashkin wrote:
> The LuaJIT's virtual machine interprets the bytecode
> following the return from function (i.e. the one succeeding
> the call made) and located on the line other than that return
> bytecode, as a new line trigger for line hooks, unlike Lua
> does.
> Here is an example (it is joined in one line intend):
> 
> debug.sethook(function(_, l) print("LINE: "..l) end, "l") loadstring("\n\ns=nil")() debug.sethook()
> 
> This chunk prints for LuaJIT:
> 
> LINE: 3
> LINE: 1
> 
> But for Lua 5.1 it is only "LINE: 3" in the output.
> See also https://github.com/tarantool/tarantool/issues/5693.
> Considering implementation-defined behaviour difference
> (see also https://luajit.org/status.html) test is disabled for
> LuaJIT.

But the commit adapts the test. Please describe how.

> 
> Closes tarantool/tarantool#5693
> Part of tarantool/tarantool#5845
> Part of tarantool/tarantool#4473

Looks like it should be 5870 instead 4473. Also, 5845 is already
closed.

> ---
> Issue: https://github.com/tarantool/tarantool/issues/5693
> GitHub branch: https://github.com/tarantool/luajit/tree/fckxorg/gh-5693-PUC-Rio-debug-line-hook
> 
>  test/PUC-Rio-Lua-5.1-tests/db.lua | 54 ++++++++++++++++---------------
>  1 file changed, 28 insertions(+), 26 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..99efe8ef 100644
> --- a/test/PUC-Rio-Lua-5.1-tests/db.lua
> +++ b/test/PUC-Rio-Lua-5.1-tests/db.lua
> @@ -8,6 +8,26 @@ do
>  local a=1
>  end
>  
> +-- The LuaJIT's virtual machine interprets the bytecode
> +-- following the return from function (i.e. the one succeeding
> +-- the call made) and located on the line other than that return
> +-- bytecode, as a new line trigger for line hooks, unlike Lua
> +-- does.
> +-- Here is an example (it is joined in one line intend):
> +--[[
> +debug.sethook(function(_, l) print("LINE: "..l) end, "l") loadstring("\n\ns=nil")() debug.sethook()
> +--]]
> +-- This chunk prints for LuaJIT:
> +--[[
> +LINE: 3
> +LINE: 1
> +--]]
> +-- But for Lua 5.1 it is only "LINE: 3" in the output.
> +-- See also https://github.com/tarantool/tarantool/issues/5693.
> +-- Considering implementation-defined behaviour difference
> +-- (see also https://luajit.org/status.html) test is disabled for
> +-- LuaJIT.

But it is not disabled after this commit.

> +-- This function is modified to correspond with LuaJIT's line triggers.
>  function test (s, l, p)
>    collectgarbage()   -- avoid gc during trace
>    local function f (event, line)
> @@ -16,7 +36,7 @@ function test (s, l, p)
>      if p then print(l, line) end
>      assert(l == line, "wrong trace!!")
>    end
> -  debug.sethook(f,"l"); loadstring(s)(); debug.sethook()
> +  local cur_line = debug.getinfo(1).currentline; table.insert(l, 1, cur_line); table.insert(l, cur_line); debug.sethook(f,"l"); loadstring(s)(); debug.sethook()

For what do we need additional insert? And why is it on the same line?

>    assert(table.getn(l) == 0)
>  end
>  
> @@ -25,7 +45,7 @@ do

<snipped>

> @@ -168,8 +170,8 @@ test([[for i,v in pairs{'a','b'} do
>  end
>  ]], {1,2,1,2,1,3})
>  
> -test([[for i=1,4 do a=1 end]], {1,1,1,1,1})
> ---]=]
> +-- Test is adapted to the behaviour of LuaJIT.
> +test([[for i=1,4 do a=1 end]], {1,1,1,1})

Why are there 4 entries instead 5?

>  
>  
>  print'+'
> -- 
> 2.33.0
> 

-- 
Best regards,
Sergey Kaplun