RSB Issue with lexicographic comparison of python versions (shown on Ubuntu 22.04 LTS/python 3.10 platform).

[Karel Gardas]

On 4/20/22 01:03, Chris Johns wrote:
> On 19/4/2022 8:06 pm, Karel Gardas wrote:
>>
>>    Chris,
>>
>> testing RSB on soon to be release Ubuntu 22.04 LTS. This distro provides python
>> 3.10 and interestingly gdb compilation fails badly on it with:
>>
>> making dir:
>> /home/karel/workspace/rtems-source-builder/rtems/build/tmp/gmp-6.1.0-x86_64-linux-gnu-1-1000/home/karel/workspace/rtems-tools/share/rtems/rsb
>>
>> reporting: devel/gmp-6.1.0.cfg -> gmp-6.1.0-x86_64-linux-gnu-1.xml
>> making dir:
>> /home/karel/workspace/rtems-source-builder/rtems/build/tmp/gmp-6.1.0-x86_64-linux-gnu-1-1000/home/karel/workspace/rtems-tools/share/rtems/rsb
>>
>> config: tools/rtems-gdb-11.2.cfg
>> error: shell macro failed:
>> /home/karel/workspace/rtems-source-builder/source-builder/sb/rtems-build-dep -c
>> gcc  -l : 2: error: no library (-l) provided
>> Build Set: Time 0:01:01.843930
>>
>>
>> The reason for this is wrong usage of probably lexicographic comparison of
>> python versions in gdb-common-1.cfg:
>>
>> Let's apply this debug patch to it and see the output:
>>
>> diff --git a/source-builder/config/gdb-common-1.cfg
>> b/source-builder/config/gdb-common-1.cfg
>> index c7f3955..45e3b88 100644
>> --- a/source-builder/config/gdb-common-1.cfg
>> +++ b/source-builder/config/gdb-common-1.cfg
>> @@ -110,6 +110,7 @@
>>     %if %{gdb-python-config} != %{nil}
>>       %define gdb-python-lib-filter awk 'BEGIN{FS="
>> "}/python/{for(i=1;i<NF;++i)if(match($i,".*lpython.*")) print
>> "lib"substr($i,3)"*";}'
>>       %if %{gdb-python-ver-mm} < 3.8
>> +        %error "not working, python is %{gdb-python-ver-mm} and yet we're in <
>> 3.8 block!"
>>           %define gdb-python-config-lib-check-flags --ldflags
>>       %else
>>           %define gdb-python-config-lib-check-flags --ldflags --embed
>>
>>
>>
>> and the output is:
>>
>> Build Set: 6/rtems-arm
>> config: tools/rtems-gdb-11.2.cfg
>> error: config error: gdb-common-1.cfg:113: "not working, python is 3.10 and yet
>> we're in < 3.8 block!"
>> Build Set: Time 0:00:00.090733
>>
>> Sorry about the %error usage, have not found any way how to debug cfg files yet
>> except of moving %error directive around...
>>
>> Do you have any idea how to make 3.10 to be bigger/higher than 3.8 in this
>> comparison?
> 
> The number 3.8 is less than 3.10 so if we changed things so it was a numeric
> check it would still fail.

No, it would not fail, since then

        %if 3.10 < 3.8
  +        %error "not working, python is %{gdb-python-ver-mm} and yet 
we're in < 3.8 block!"
            %define gdb-python-config-lib-check-flags --ldflags
        %else
            %define gdb-python-config-lib-check-flags --ldflags --embed

will evaluate to else block which is exactly what we need for python 3.10.

> I suggest %{gdb-python-ver-mm} is split into major and minor parts and each checked:
> 
> %define gdb-python-ver-major %(echo "%{gdb-python-ver-mm}" | sed -e 's/\..*//')
> %define gdb-python-ver-minor %(echo "%{gdb-python-ver-mm}" | sed -e 's/.*\.//')
> 
> then:
> 
>    %if %{gdb-python-ver-major} < 3 && %{gdb-python-ver-minor} < 8

I would guess this should be

     %if %{gdb-python-ver-major} <= 3 && %{gdb-python-ver-minor} < 8

but otherwise yes, if we're really going this route.

The question is still why we cannot use simple numerical comparison 
above... This would mean less code -> less bugs. Be more intuitive etc.

Thanks!
Karel