Re: Explicitly warn about lua_next missing an order guarantee in the reference manual

As said, this bug often does not surface because most lists live in the 
array part, as they ideally should. (I originally said tables, should 
have said lists to be precise.)

But if you populate a table in a nonstandard order, or using the right 
table constructor syntax, you /will/ get lists that partially or fully 
live in the hash part.

For example, see what happens when you iterate the table {[1] = 1, [2] 
= 2, [3] = 3}
using pairs() on PUC Lua (if you get the expected order, maybe retry a 
few times, or add more entries).

For the same reason we tell Lua programmers not to expect pairs() to 
iterate a table in order,
we should tell C programmers not to expect lua_next() to iterate a 
table in order.

And as said, I think that it would be highly beneficial if a sentence 
or two to that effect
were added to the section on lua_next() in the reference manual.
So I hope one of the Lua authors sees this and updates it.

- Lars

On Thu, Apr 16 2026 at 00:00:47 +00:00:00, 'Sainan' via lua-l 
<[email protected]> wrote:
>>  The order in which the indices are enumerated is not specified, 
>> even for numeric indices.
> 
> Well, the order is guaranteed for numeric indecies, as long as those 
> numeric indecies start at 1 and increment from there. :^)
> 
> -- Sainan
> 
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