io.open(filename, "w") should truncate file

[waschik]

You must post issues only here. Questions, ideas must be posted in discussions.

• GopherLua is a Lua5.1 implementation. You should be familiar with Lua programming language. Have you read Lua 5.1 reference manual carefully?
• GopherLua is a Lua5.1 implementation. In Lua, to keep it simple, it is more important to remove functionalities rather than to add functionalities unlike other languages . If you are going to introduce some new cool functionalities into the GopherLua code base and the functionalities can be implemented by existing APIs, It should be implemented as a library.

Please answer the following before submitting your issue:

1. What version of GopherLua are you using? : 1.1.0 (fa815b5)
2. What version of Go are you using? : go version go1.19.2 linux/amd64
3. What operating system and processor architecture are you using? : x86_64 GNU/Linux
4. What did you do? :

I use this test script (test.lua):

local function write(filename, content)
local f = assert(io.open(filename, "w"))
  f:write(content)
  assert(f:close())
end

local filename = "test.txt"
os.remove(filename)
write(filename, "abcdef\n")
write(filename, "g\n")

5. What did you expect to see? :

If I use 5.1 lua of system I get this output:

$ lua -v
Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
$ lua test.lua && cat test.txt 
g

Unfortunately the manual does not explicitly tells that file must be truncated: https://www.lua.org/manual/5.1/manual.html#5.7 But for fopen this is standard: https://man7.org/linux/man-pages/man3/fopen.3.html Programming in lua mention also erase of "w" https://www.lua.org/pil/21.2.html: "`w´ for writing (which also erases any previous content of the file)"

6. What did you see instead? :

$ ./glua test.lua && cat test.txt 
g
cdef