[U-Boot] [PATCH v2] kconfig: convert Kconfig helper script into a shell script

[Masahiro Yamada]

Hi Stephen,


On Mon, 18 Aug 2014 10:36:48 -0600
Stephen Warren <swarren at wwwdotorg.org> wrote:

> On 08/18/2014 10:27 AM, Simon Glass wrote:
> > Hi,
> >
> > On 18 August 2014 10:20, Stephen Warren <swarren at wwwdotorg.org
> > <mailto:swarren at wwwdotorg.org>> wrote:
> >
> >     On 08/16/2014 10:56 PM, Masahiro Yamada wrote:
> >
> >         Commit 51148790 added scripts/multiconfig.py written in Python 2
> >         to adjust Kconfig for U-Boot.
> >
> >         It has been hard for Python 3 users because Python 2 and Python 3
> >         are not compatible with each other.
> >
> >         We are not happy about adding a new host tool dependency
> >         (in this case, Python version dependency) for the core build
> >         process.
> >         After some discussion, we decided to use only basic tools.
> >
> >         The script may get a bit unreadable by shell scripting, but we
> >         believe
> >         it is worthwhile.
> >
> >         In addition, this commit revives "<board>_config" target that is
> >         equivalent to "<board>_defconfig" for backwards compatibility.
> >         It is annoying to adjust various projects which use U-Boot.
> >
> >
> >     Personally, I think this change isn't justified; I see no reason to
> >     replace the perfectly working existing script. Still, if that's
> >     what's desired...
> >
> >
> > Agreed, it seems unfortunate - long shell scripts are so much harder to
> > work with IMO. Is it really not possible to make code compatible with
> > both? Also we have lost the docs at the top of the file I think.
> 
> It might well be possible to be compatible with both Python 2 and 3, but the solution mentioned earlier in the thread was as simple as:
> 
> - #!/usr/bin/python
> + #!/usr/bin/python2



We can change the top Makefile as follows:


 diff --git a/Makefile b/Makefile
 index b5d5e01..e830d3d 100644
 --- a/Makefile
 +++ b/Makefile
 @@ -338,7 +338,7 @@ OBJCOPY             = $(CROSS_COMPILE)objcopy
  OBJDUMP                = $(CROSS_COMPILE)objdump
  AWK            = awk
  PERL           = perl
 -PYTHON         = python
 +PYTHON         = python2
  DTC            = dtc
  CHECK          = sparse
 



> That would only fail on systems:
> 
> a) Without Python2 (which seems a little unlikely at the moment, and even if that's the case by default, there's enough Python2 code that surely a compat package would be available)
> 
> b) So old that there is no python2 symlink, just python. I don't know when python2 was added.


To be more supportive for b), we can also do

PYTHON         = $(if $(shell which python2 2>/dev/null), python2, python)


I don't know exactly when 'python2' was added
but I think it existed at least from python 2.4.
We can not (need not) support older versions than it.
The switch above might not be necessary.



Best Regards
Masahiro Yamada