NullPage that lacks ID in PageArray causes invalid selectors

[Toutouwai]

Short description of the issue

The docs for NullPage state that:

The id property will always be 0 for a NullPage.

But this doesn't seem to be the case and it can cause and invalid selector when a NullPage exists in a PageArray and that PageArray is then used in a selector string (making use of PageArray::__toString).

Demo case:

The general point here is that it ought to be safe to use a PageArray in a selector without the user first needing to look for and remove any pages that lack an ID.

Setup/Environment

• ProcessWire version: 3.0.236

[Toutouwai]

It looks like the issue is with NullPage::__toString. Why does it override Page::__toString(), which would otherwise return '0' and allow PageArray::__toString to work as expected in selectors?

[ryancramerdesign]

Thanks @Toutouwai I've pushed a fix for this issue. I'm not sure PageArray should allow a NullPage to exist in it, but since it already does I don't think I should change it. The reason a NullPage string value is blank string rather than '0' string is because that differentiates it from a regular page that doesn't yet have an ID (i.e. a new Page that hasn't been saved yet.)

[Toutouwai]

Thanks