Re: [oe-core][PATCHv2] cpan: do not rebuild the Makefile when perls config is re-staged

[Paul Barker <paul@pbarker.dev>]

On Tue, 2026-09-29 at 23:54 +0200, Markus Volk wrote:
> On Tue, Sep 29 2026 at 18:56:26 +02:00:00, Alexander Kanavin 
> <alex.kanavin@gmail.com> wrote:
> > Why is it failing? Shouldn't we fix the fail instead of suppressing 
> > the regeneration?
> > 
> > Alex
> 
> The failure is intentional on MakeMaker side. This is the rule it 
> writes into every Makefile
> 
> $(FIRST_MAKEFILE) : Makefile.PL $(CONFIGDEP)
>       $(NOECHO) $(ECHO) "Makefile out-of-date with respect to $?"
>       ...
>       -$(NOECHO) $(MV)   $(FIRST_MAKEFILE) $(MAKEFILE_OLD)
>       - $(MAKE) $(USEMAKEFILE) $(MAKEFILE_OLD) clean $(DEV_NULL)
>       $(PERLRUN) Makefile.PL <original args>
>       $(NOECHO) $(ECHO) "==> Your Makefile has been rebuilt. <=="
>       $(NOECHO) $(ECHO) "==> Please rerun the $(MAKE) command.  <=="
>       $(FALSE)
> 
> The only way to "fix the fail" is to run make a second time. That is 
> what the first version did
> 
> Regenerating the Makefile inside do_compile/do_install is not correct 
> for us because it skips the do_configure fixups.
> The trigger is only a timestamp. CONFIGDEP is Config.pm and config.h of 
> the staged perl. do_prepare_recipe_sysroot re-stages them, and the 
> FIXMESTAGINGDIR sed in staging.bbclass rewrites them, so they get a new 
> mtime even though their content matches what do_configure saw. If perl 
> really changes, the task hash changes and bitbake reruns do_configure 
> anyway. That path does apply the fixups.
> 
> The correct way to regenerate the Makefile is do_configure, and bitbake 
> already takes care of that. Clearing CONFIGDEP only stops make from 
> reacting to a timestamp that means nothing inside a bitbake build. 
> Makefile.PL itself stays a dependency, so a changed Makefile.PL would 
> still be noticed.

Hi Markus,

There is another possible approach here. We could modify
staging_processfixme() to preserve the mtime of the files it modifies.
That should prevent cpan Makefiles from being considered out-of-date
when perl is re-staged.

Thanks,

-- 
Paul Barker