I really don't like all of these recent ideas to let Lua fetch information about pages that isn't known until the page is parsed.

In T131911#2183910, @Jackmcbarn wrote:

I really don't like all of these recent ideas to let Lua fetch information about pages that isn't known until the page is parsed.

MZ and I discussed on IRC that we could only allow lookups of *other* pages so you'd never run into the issue of trying to depend on something that is determined in the current parse.

In T131911#2183976, @Legoktm wrote:

In T131911#2183910, @Jackmcbarn wrote:

I really don't like all of these recent ideas to let Lua fetch information about pages that isn't known until the page is parsed.

MZ and I discussed on IRC that we could only allow lookups of *other* pages so you'd never run into the issue of trying to depend on something that is determined in the current parse.

That feels clunky, though, and it doesn't completely fix the problem. If page A referenced page B and page B referenced page A, you'd still get the same issue.

In T131911#2183990, @Jackmcbarn wrote:

That feels clunky, though, and it doesn't completely fix the problem. If page A referenced page B and page B referenced page A, you'd still get the same issue.

I don't follow. It should be possible to programmatically retrieve attributes/properties of a wiki page such as page length in bytes, display title, page image, etc. via parser functions or via Scribunto/Lua, in my opinion. I'm not sure how we'd have circular references with page images.

Looking at https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Title_objects, extending a title object to support retrieving a few additional properties seems reasonable. As Lego says, we're talking about retrieving info about other pages, so it should be less volatile.

Cross-reference: https://www.mediawiki.org/wiki/Requests_for_comment/Accessing_page_properties_from_wiki_pages.