Editing Module talk:Arguments (section)

== Pairs bug ==

I've just found a bug in the pairs code of this module. It turns out that if you delete a value in the args table by setting it to nil, the the value is still present if you access the args table with pairs. There's a demonstration of the bug in [https://en.wikipedia.org/w/index.php?title=Module:User:Mr._Stradivarius/sandbox&oldid=637283032 my sandbox], and I've added two new test cases which are [[Module talk:Arguments/testcases|currently failing]].

To fix this, it looks like we would need a new table to memoize nils. We need to check whether an argument has been expressly deleted when calling mergeArgs, but at the same time, values in nilArgs need to be overwritable for precedence whitespace arguments to work properly. I don't see how one table can fulfil both functions.

Alternatively, we could get away with using one nilArgs table if we change the module to only ever check the frame args or the parent frame args, and never both. If I remember rightly, this is what the proposed getArgs function inside Scribunto does, so if that solution seems better we could wait for that function to be deployed and then switch all of our existing modules over to it. — '''''[[User:Mr. Stradivarius|<span style="color: #194D00; font-family: Palatino, Times, serif">Mr. Stradivarius</span>]]''''' <sup>[[User talk:Mr. Stradivarius|♪ talk ♪]]</sup> 06:59, 9 December 2014 (UTC)
:{{ping|Mr. Stradivarius}} There is one edge case in the new getArgs function that would still read both, so that won't save us. However, I did find a way to make it work without adding an additional table. It's in the sandbox. [[User:Jackmcbarn|Jackmcbarn]] ([[User talk:Jackmcbarn|talk]]) 15:11, 9 December 2014 (UTC)
::{{ping|Jackmcbarn}} Yes, that looks like a good approach to solving it - definitely better than introducing another table. Instead of using trinary logic, how about using strings to denote the status, similar to what Lua does with __mode? I think that would make the code more readable. We could use 'hard' and 'soft' for hard and soft nils, or just 'h' and 's' if we want to be concise. — '''''[[User:Mr. Stradivarius|<span style="color: #194D00; font-family: Palatino, Times, serif">Mr. Stradivarius</span>]]''''' <sup>[[User talk:Mr. Stradivarius|♪ talk ♪]]</sup> 15:55, 9 December 2014 (UTC)
:::{{ping|Mr. Stradivarius}} Okay, that's done. [[User:Jackmcbarn|Jackmcbarn]] ([[User talk:Jackmcbarn|talk]]) 04:11, 10 December 2014 (UTC)
::::{{ping|Jackmcbarn}} Looks good. Unless there's anything else you would like to change, I think we're ok to update the main module now. — '''''[[User:Mr. Stradivarius|<span style="color: #194D00; font-family: Palatino, Times, serif">Mr. Stradivarius</span>]]''''' <sup>[[User talk:Mr. Stradivarius|♪ talk ♪]]</sup> 04:37, 10 December 2014 (UTC)
:::::{{ping|Mr. Stradivarius}} Actually, there is, but I can't do it yet. Once the inexpensive mw.title.new change gets here, I want to make this use mw.title.new to normalize wrapper names (to make less stuff break when our modules get transwikied to wikis with different namespace names). [[User:Jackmcbarn|Jackmcbarn]] ([[User talk:Jackmcbarn|talk]]) 03:57, 11 December 2014 (UTC)
::::::{{ping|Jackmcbarn}} Ok, but I don't think there's any need to wait for that before we fix the current bug. I'll go and update the module now. — '''''[[User:Mr. Stradivarius|<span style="color: #194D00; font-family: Palatino, Times, serif">Mr. Stradivarius</span>]]''''' <sup>[[User talk:Mr. Stradivarius|♪ talk ♪]]</sup> 04:27, 11 December 2014 (UTC)
:::::::Okay. [[User:Jackmcbarn|Jackmcbarn]] ([[User talk:Jackmcbarn|talk]]) 04:28, 11 December 2014 (UTC)