The issue is with https://www.wikidata.org/wiki/MediaWiki:Search-nonefound having {{#switch:{{NAMESPACENUMBER:$1}} and $1 being -{ for the example problematic URL, which doesn't work because its an invalid title

In T278658#6952684, @matej_suchanek wrote:

Reopening because I don't know how to solve it locally (other than by reverting T263258 or even T132729).

Maybe add <nowiki> mark around $1 can slove it.

In T278658#6984320, @Func wrote:

Maybe add <nowiki> mark around $1 can slove it.

$1 is already escaped, so this is unnecessary. Adding around $2 won't help because {{urlencode:<nowiki>$2</nowiki>|PATH}} returns nothing (we could live with not having returned anything for "invalid" input but not for valid).

Oh, the problem is that title with big quote isn't a valid title, and unpaired big quotes broke the parsing process. Maybe we can check the title in lua module, with mw.title.new and check the return value...

In T278658#6991622, @Func wrote:

Oh, the problem is that title with big quote isn't a valid title, and unpaired big quotes broke the parsing process. Maybe we can check the title in lua module, with mw.title.new and check the return value...

And all wikitext with plain $2 (without nowiki marks) should move to lua module to not break parsing process.

In T278658#6991639, @Func wrote:

In T278658#6991622, @Func wrote:

Oh, the problem is that title with big quote isn't a valid title, and unpaired big quotes broke the parsing process. Maybe we can check the title in lua module, with mw.title.new and check the return value...

And all wikitext with plain $2 (without nowiki marks) should move to lua module to not break parsing process.

Very good idea! It seems not to break, but the form is now prefilled with -&#123; (not a big problem)...

In T278658#6992034, @matej_suchanek wrote:

Very good idea! It seems not to break, but the form is now prefilled with -&#123; (not a big problem)...

Maybe the text was escaped by nowiki or unstripNoWiki...