submenu fails to see variables

submenu fails to see variables

[Olaf Hering]

[-- Attachment #1: Type: text/plain, Size: 325 bytes --]

For some reason global variables are not seen in a submenu {} section.
Does anyone happen to know why this behavior is useful?

Pseudocode:

set var=val
menuentry "me" {
 set
 echo "var ${var}"
 sleep 3
}

submenu "sm" {
 set
 echo "var ${var}"
 sleep 3
}

Seen with grub 2.02 and 2.04.


Thanks,
Olaf

[-- Attachment #2: Digitale Signatur von OpenPGP --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: submenu fails to see variables

[Vladimir 'phcoder' Serbinenko]

[-- Attachment #1: Type: text/plain, Size: 659 bytes --]

Le lun. 6 sept. 2021 à 12:49, Olaf Hering <olaf@aepfle.de> a écrit :

> For some reason global variables are not seen in a submenu {} section.
> Does anyone happen to know why this behavior is useful?
>
You need to export variable to make it visible in submenu

>
> Pseudocode:
>
> set var=val
> menuentry "me" {
>  set
>  echo "var ${var}"
>  sleep 3
> }
>
> submenu "sm" {
>  set
>  echo "var ${var}"
>  sleep 3
> }
>
> Seen with grub 2.02 and 2.04.
>
>
> Thanks,
> Olaf
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
>

[-- Attachment #2: Type: text/html, Size: 1398 bytes --]

Re: submenu fails to see variables

[Olaf Hering]

On Mon, Sep 06, Vladimir 'phcoder' Serbinenko wrote:

> Le lun. 6 sept. 2021 à 12:49, Olaf Hering <olaf@aepfle.de> a écrit :
>     For some reason global variables are not seen in a submenu {} section.
>     Does anyone happen to know why this behavior is useful?
> You need to export variable to make it visible in submenu

Thanks. This was less than obvious. I did not expect a command named 'export' in the context of grub.

The documentation needs to be updated to state what the difference between 'set key=val', 'export key=val' and plain 'key=val' actually is.

Olaf

Re: submenu fails to see variables

[Dimitri John Ledkov]

On Tue, Sep 7, 2021 at 10:30 AM Olaf Hering <olaf@aepfle.de> wrote:
>
> On Mon, Sep 06, Vladimir 'phcoder' Serbinenko wrote:
>
> > Le lun. 6 sept. 2021 à 12:49, Olaf Hering <olaf@aepfle.de> a écrit :
> >     For some reason global variables are not seen in a submenu {} section.
> >     Does anyone happen to know why this behavior is useful?
> > You need to export variable to make it visible in submenu
>
> Thanks. This was less than obvious. I did not expect a command named 'export' in the context of grub.
>
> The documentation needs to be updated to state what the difference between 'set key=val', 'export key=val' and plain 'key=val' actually is.

I have seen somewhere that some distros applied a patch to simply
export all variables always; or like not to create new contexts for
submenus, to keep the variable space the same.

Imho keeping variable space global, and exported by default seems to
lead to least surprises. But it is a behaviour change/break.

Re: submenu fails to see variables

[Daniel Kiper]

On Tue, Sep 07, 2021 at 11:54:13AM +0100, Dimitri John Ledkov wrote:
> On Tue, Sep 7, 2021 at 10:30 AM Olaf Hering <olaf@aepfle.de> wrote:
> >
> > On Mon, Sep 06, Vladimir 'phcoder' Serbinenko wrote:
> >
> > > Le lun. 6 sept. 2021 à 12:49, Olaf Hering <olaf@aepfle.de> a écrit :
> > >     For some reason global variables are not seen in a submenu {} section.
> > >     Does anyone happen to know why this behavior is useful?
> > > You need to export variable to make it visible in submenu
> >
> > Thanks. This was less than obvious. I did not expect a command named 'export' in the context of grub.
> >
> > The documentation needs to be updated to state what the difference between 'set key=val', 'export key=val' and plain 'key=val' actually is.
>
> I have seen somewhere that some distros applied a patch to simply
> export all variables always; or like not to create new contexts for
> submenus, to keep the variable space the same.
>
> Imho keeping variable space global, and exported by default seems to
> lead to least surprises. But it is a behaviour change/break.

I would prefer to keep behavior as is and document it.

Dimitri, Olaf, could one of you do it?

Daniel