[Tarantool-patches] [PATCH luajit v2] test: adapt tests checking debug line hook trace

[Maxim Kokryashkin]

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 tarantool/tarantool#5693.

Those tests are adapted to LuaJIT behavior by changing assertions
considering line events that LuaJIT generates.

Part of tarantool/tarantool#5870
---
Changes in v2:
- Fixed comments as per review by Sergey
- Added some comments

 test/PUC-Rio-Lua-5.1-tests/db.lua | 57 +++++++++++++++++--------------
 1 file changed, 31 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..120fc04c 100644
--- a/test/PUC-Rio-Lua-5.1-tests/db.lua
+++ b/test/PUC-Rio-Lua-5.1-tests/db.lua
@@ -8,6 +8,23 @@ 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.
+-- 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)
@@ -16,6 +33,11 @@ function test (s, l, p)
     if p then print(l, line) end
     assert(l == line, "wrong trace!!")
   end
+  -- Despite `loadstring` and `debug.sethook` are on the same line, LuaJIT
+  -- generates separate line events for them. The test is adapted to LuaJIT
+  -- behavior by adding corresponding line numbers into the test table.
+  table.insert(l, 1, 41)
+  table.insert(l, 41)
   debug.sethook(f,"l"); loadstring(s)(); debug.sethook()
   assert(table.getn(l) == 0)
 end
@@ -25,8 +47,8 @@ do
   local a = debug.getinfo(print)
   assert(a.what == "C" and a.short_src == "[C]")
   local b = debug.getinfo(test, "SfL")
-  assert(b.name == nil and b.what == "Lua" and b.linedefined == 11 and
-         b.lastlinedefined == b.linedefined + 10 and
+  assert(b.name == nil and b.what == "Lua" and b.linedefined == 28 and
+         b.lastlinedefined == b.linedefined + 15 and
          b.func == test and not string.find(b.short_src, "%["))
   assert(b.activelines[b.linedefined + 1] and
          b.activelines[b.lastlinedefined])
@@ -95,26 +117,6 @@ repeat
   assert(g(f) == 'a')
 until 1

--- FIXME: 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.
---[=[
 test([[if
 math.sin(1)
 then
@@ -132,23 +134,25 @@ else
 end
 ]], {2,5,6})

+-- Test is adapted to the behaviour of LuaJIT.
 test([[a=1
 repeat
   a=a+1
 until a==3
-]], {1,3,4,3,4})
+]], {1,2,3,4,2,3,4})

 test([[ do
   return
 end
 ]], {2})

+-- Test is adapted to the behaviour of LuaJIT.
 test([[local a
 a=1
 while a<=3 do
   a=a+1
 end
-]], {2,3,4,3,4,3,4,3,5})
+]], {1,2,3,4,3,4,3,4,3,5})

 test([[while math.sin(1) do
   if math.sin(1)
@@ -168,8 +172,9 @@ 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, as it generates only four line
+-- events, unlike Lua, which generates five of them.
+test([[for i=1,4 do a=1 end]], {1,1,1,1})


 print'+'
--
2.33.0