bug#74087: Bug patch: invoke tab-bar-tab-post-open-functions during tabs initialization

[Juri Linkov <juri@linkov.net>]

> A pre-open tab hook, though, might be useful for pinning cases if it would
> allow influencing the tab position as a function value. I could think on
> that separately from the proposed patch and see if I can simplify pinning
> as a result (which is already a pain in the neck and quite imperfect).
>
> On Tue, Oct 29, 2024 at 3:23 PM Ship Mints <shipmints@gmail.com> wrote:
>
>     In a pre-open hook, I'd expect to be able to deny a new tab being
>     opened, for example, if I want a tab-bar with a fixed set of tabs. That
>     seems like a different use-case from operating on a tab after it's
>     officially created even if not yet visible.
>
>     On Tue, Oct 29, 2024 at 3:18 PM Ship Mints <shipmints@gmail.com> wrote:
>
>         That's not a good assumption, though. The motivation behind putting
>         the open hook call after the tabs are set on the frame is to allow
>         users to use the frame tabs as they would for tabs created at any
>         other time with no special casing. I don't think we need a special
>         case, just treat all tabs the same, first or beyond.

The hook 'tab-bar-tab-post-open-functions' can't be called from 'tab-bar-tabs'
because no new tab is opened from 'tab-bar-tabs'.  The initial tab already exists.

What could be done in 'tab-bar-tabs' is to call a completely new hook named
'tab-bar-init'.