Re: [RFC] Edk2 BaseTools Python3 Migration Update

["Gao, Liming" <liming.gao@intel.com>]

Jaben:
  I also think this way. Now, we have two envs PYTHON3_ENABLE and PYTHON_COMMAND. The behavior can be combined as the below to support this usage. If user wants the specific python interpreter, he only needs to set PYTHON_COMMAND env.

If PYTHON3_ENABLE is set, PYTHON_COMMAND will be set to the found one by edk2 scripts based on PYTHON3_ENABLE value. 
If PYTHON3_ENABLE is not set, but PYTHON_COMMAND is set, then PYTHON_COMMAND will be used to run python script. No version check here. 
If PYTHON3_ENABLE is not set, but PYTHON_COMMAND is not set, PYTHON_COMMAND will be set to the high version python installed in OS. 

Thanks
Liming
>-----Original Message-----
>From: Carsey, Jaben
>Sent: Wednesday, January 09, 2019 2:06 AM
>To: Laszlo Ersek <lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>;
>Ni, Ray <ray.ni@intel.com>; edk2-devel@lists.01.org; leif.lindholm@linaro.org;
>afish@apple.com; Kinney, Michael D <michael.d.kinney@intel.com>
>Subject: RE: [edk2] [RFC] Edk2 BaseTools Python3 Migration Update
>
>
>
>> -----Original Message-----
>> From: Laszlo Ersek [mailto:lersek@redhat.com]
>> Sent: Tuesday, January 08, 2019 9:26 AM
>> To: Carsey, Jaben <jaben.carsey@intel.com>; Gao, Liming
>> <liming.gao@intel.com>; Ni, Ray <ray.ni@intel.com>; edk2-
>> devel@lists.01.org; leif.lindholm@linaro.org; afish@apple.com; Kinney,
>> Michael D <michael.d.kinney@intel.com>
>> Subject: Re: [edk2] [RFC] Edk2 BaseTools Python3 Migration Update
>> Importance: High
>>
>> On 01/08/19 17:22, Carsey, Jaben wrote:
>> > Liming and Laszlo,
>> > 	What if we add a 4th option to the environment variable - the path to
>> a specific python interpreter for use.
>>
>> I thought of that, but how do the build tools derive the python version
>> just from the pathname of the interpreter?
>>
>> Will they run "$INTERPRETER --version" and parse the output?
>>
>> I think that could be brittle; distributions sometimes customize the
>> version strings of their executables. The "--version" output is usually
>> human-readable, not machine-readable (per intent).
>
>Laszlo, you lost me. How is that related to an exact path?   If the user specifies
>the path, then always use that specific interpreter.
>
>>
>> Thanks,
>> Laszlo
>>
>> >
>> > -Jaben
>> >
>> >
>> >> -----Original Message-----
>> >> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf
>Of
>> >> Gao, Liming
>> >> Sent: Tuesday, January 08, 2019 6:23 AM
>> >> To: Laszlo Ersek <lersek@redhat.com>; Ni, Ray <ray.ni@intel.com>;
>edk2-
>> >> devel@lists.01.org; leif.lindholm@linaro.org; afish@apple.com; Kinney,
>> >> Michael D <michael.d.kinney@intel.com>
>> >> Subject: Re: [edk2] [RFC] Edk2 BaseTools Python3 Migration Update
>> >>
>> >> Laszlo:
>> >>   Yes. This can be supported. But, I don't know what purpose to specify
>> >> python minor version of Python3. Current implementation in Python3
>> branch
>> >> always tries to find the high version installed in OS. For example,
>> Python3.4,
>> >> Python3.7 are both installed, Python3.7 will be chosen. Does this policy
>> meet
>> >> with your usage?
>> >>
>> >> Thanks
>> >> Liming
>> >>> -----Original Message-----
>> >>> From: Laszlo Ersek [mailto:lersek@redhat.com]
>> >>> Sent: Tuesday, January 8, 2019 3:04 AM
>> >>> To: Gao, Liming <liming.gao@intel.com>; Ni, Ray <ray.ni@intel.com>;
>> edk2-
>> >> devel@lists.01.org; leif.lindholm@linaro.org;
>> >>> afish@apple.com; Kinney, Michael D <michael.d.kinney@intel.com>
>> >>> Subject: Re: [edk2] [RFC] Edk2 BaseTools Python3 Migration Update
>> >>>
>> >>> On 01/07/19 14:41, Gao, Liming wrote:
>> >>>> Ray:
>> >>>>  I think this proposal is good to recommend Python3 as the default
>> >> interpreter. I summary the updated proposal.
>> >>>>
>> >>>> 1. PYTHON3_ENABLE env is not set. edksetup.bat/edksetup.sh will
>find
>> >> higher version python installed in OS. If Python3 is found,
>> >>> Python3 will be used. Then, if python2 is found, and python2 is used. If
>> not
>> >> found, report error and stop build. This will change the
>> >>> default python interpreter from Python2 to Python3 when they both
>are
>> >> installed.
>> >>>> 2. PYTHON3_EANBLE env is set to TRUE. edksetup.bat/edksetup.sh
>will
>> >> find Python3. If Python3 is found, Python3 will be used. If not
>> >>> found, report error and stop build.
>> >>>> 3. PYTHON3_ENABLE env is set to not TRUE.
>edksetup.bat/edksetup.sh
>> >> will find Python2. If Python2 is found, Python2 will be used. If
>> >>> not found, report error and stop build.
>> >>>> Once Python is found, edksetup.bat/edksetup.sh and build tool will
>> both
>> >> print message to let user aware which version python tool is
>> >>> used in this build.
>> >>>
>> >>> If we're going for this level of flexibility, I'd like to suggest /
>> >>> request another improvement. Some Linux distros intend to
>> accommodate
>> >>> multiple Python3 versions at the same time (this is not a typo; I don't
>> >>> mean Python2+Python3, but multiple Python3 versions). So basically I'd
>> >>> suggest that we offer a method for specifying a python version
>> >>> (2/3/auto-detect), plus, in case a specific major version is specified,
>> >>> that we allow the user to specify the precise interpreter pathname too.
>> >>>
>> >>> Thanks,
>> >>> Laszlo
>> >> _______________________________________________
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