is_true, is_false and is_type may throw an error on Lua >= 5.2.2 about luassert HOT 9 CLOSED

Update: I'm sorry for not providing an actual example.

> assert = require "luassert"
> assert.is_true()
/usr/local/share/lua/5.2/luassert/assertions.lua:97: bad argument #2 to 'insert' (position out of bounds)
stack traceback:
    [C]: in function 'insert'
    /usr/local/share/lua/5.2/luassert/assertions.lua:97: in function 'callback'
    /usr/local/share/lua/5.2/luassert/assert.lua:54: in function 'is_true'
    stdin:1: in main chunk
    [C]: in ?

The error is only raised under Lua >= 5.2.2.

I'll try to make a pull request fixing the issue.

from luassert.

This is what I get;

C:\Users\Thijs>lua52
Lua 5.2.1  Copyright (C) 1994-2012 Lua.org, PUC-Rio
> assert = require("luassert")
> assert.is_true()
stdin:1: Expected objects to be the same. Passed in:
(nil)
Expected:
true
stack traceback:
        [C]: in function 'error'
        ...(x86)\LuaRocks\systree\share\lua\5.1\luassert\assert.lua:60: in function 'is_true'
        stdin:1: in main chunk
        [C]: in ?
>

Has your interpreter been compiled without the 'compatibility' flag?

What happens when you run the luassert test suite?

from luassert.

@Tieske, I checked Lua source and the check doesn't depend on the compatibility flag, but it was only introduced in Lua 5.2.2. 5.2.1 5.2.2

Luassert test suite fails, most errors are related to this issue.

from luassert.

It looks like the lua developers decided that table.insert should treat tables only as arrays as of lua 5.2.2. They do not allow insertion at arbitrary indices.

I suggest we change the offending line in assertions to read

arguments[2] = true

instead of

table.insert(arguments, 2, true)

from luassert.

This will need to be changed for the other assertions as well. I don't understand why they did this to us. The change in lua 5.2 seems...silly. The only thing I can think of is that they didn't want undefined behavior for sparse arrays?

from luassert.

I think the best solution would be to create a local tinsert() function that does the right thing and replace all calls to table.insert() with that.

from luassert.

What is your reasoning on why calling tinsert is best?

from luassert.

There is even utils.tinsert implemented already which seems to do the right thing.

from luassert.

@DorianGray because stock Lua is bad at handling nils. And luassert really needs it. That is why utils.tinsert was added in the first place.

Imo it would provide least chance of problems

@mpeterv thanks for bringing that back to memory!

from luassert.