Re: 01/02: build: gnu-build-system: Don't run configure during bootstrap.

[Bengt Richter]

Hi Efraim,

On +2020-02-16 16:55:17 +0200, Efraim Flashner wrote:
> On Sun, Feb 16, 2020 at 03:27:36PM +0100, Marius Bakke wrote:
> > address@hidden writes:
> > 
> > > commit 481a0f1a7ceac666a011b28324220584ead07698
> > > Author: Efraim Flashner <address@hidden>
> > > AuthorDate: Thu Feb 13 10:54:29 2020 +0200
> > >
> > >     build: gnu-build-system: Don't run configure during bootstrap.
> > >     
> > >     * guix/build/gnu-build-system.scm (bootstrap): Add NOCONFIGURE
> > >     environment variable before running bootstrap scripts.
> > 
> > [...]
> > 
> > > @@ -190,6 +190,7 @@ working directory."
> > >                (if (executable-file? script)
> > >                    (begin
> > >                      (patch-shebang script)
> > > +                    (setenv "NOCONFIGURE" "true")
> > >                      (invoke script))
> > >                    (invoke "sh" script)))
> > >              (if (or (file-exists? "configure.ac")
> > 
> > Should we unset NOCONFIGURE afterwards?  Probably at least one package
> > uses this variable for something completely different...
> 
> It probably wouldn't hurt to unset it. I've never come across a package
> where that's been a problem but best not invite trouble.
>
With all due respect, I am not comfortable with this kind of rationale :) 

If it's never been a problem, unsetting might hide a case where it _would_
cause a problem -- which IMO it would be better to find out about than not.

Is there an official policy regarding garbage/dangling environment variables?

(Or is that just to be expected in the sargasso sea of "undefined behaviour"? 
;-)

So, if in doubt, instead of unsetting, perhaps set it something like

    "IF_YOU_SEE_THIS_PLEASE_REPORT_HOW_IT_HAPPENED_TO_efraim_AT_flashner.co.il"

;-P

or make it throw an exception somehow, if following processing uses NOCONFIGURE
any way at all before being replaced with a proper meaningful new value.

> Also, looking at the snippet, I should move it higher up. If it's not
> executable then NOCONFIGURE doesn't get set.
> 
> 
> -- 
> Efraim Flashner   <address@hidden>   אפרים פלשנר
> GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
> Confidentiality cannot be guaranteed on emails sent or received unencrypted

Hope I didn't offend anyone :)
-- 
Regards,
Bengt Richter