bug#42045: 27.0.91; display-format-alist for X11 does not recognize DISPLAY with IPv6 literal

[Valtteri Vuorikoski]

On 9/1/20 5:36 PM, Robert Pluim wrote:
> > > > > > On Thu, 25 Jun 2020 22:20:05 +0300, Valtteri Vuorikoski <vuori@notcom.org> said:
>
>      Valtteri> If the DISPLAY environment variable is to an IPv6 literal such as
>      Valtteri> [::1]:1, the regexp that x-win.el adds to the 
> display-format-alist to
>      Valtteri> recognize X11 does not match, which results in breakage.
>
>      Valtteri> x-win.el should probably add a second regexp to the alist, such 
> as:
>      Valtteri> (add-to-list 'display-format-alist 
> '("\\`\\[[^]]*\\]:[0-9]+\\(\\.[0-9]+\\)?\\'" . x))
>
> That regexp won't work, since now youʼre requiring the '[' and ']' to
> be present.
>
> "\\`\\[?[^]]*\\]?:[0-9]+\\(\\.[0-9]+\\)?\\'" would fix that, but since
> we donʼt really care what comes before the ':', so would
>
> "\\`.*:[0-9]+\\(\\.[0-9]+\\)?\\'"

Yes, note "second regexp": the current regexp would remain and match 
other types of hostnames/addresses. But if no one cares about the format 
of the host part, your version is simpler.

 -Valtteri