bazel 4.2 and 3.7 no longer building with native clang

[Chris Jones]

On 14/07/2022 12:23 pm, Steven Smith wrote:
>> I've conceded defeat to bazel. I've lost interest in the battle but I wish you luck if you wish to take it up...
> 
> 
> My interest in bazel is the minimum necessary to get tensorflow-related projects working.

That was also my starting point. Unfortunately the rabbit hole proved to 
be very very deep..

> 
> FWIW, bazel 5 builds and works on macOS, but previous versions do not, and I strongly doubt whether any magic selection of compiler will get them to work: https://github.com/bazelbuild/bazel/issues/15876

The bazel port indeed provides a number of builds. The primary one which 
I used to try and keep up with the latest release, and a bunch of 
sub-ports that only exist because tensorflow usually has a maximum 
version it will support using. So the versions there are literally only 
there to support the versions previously needed. Please feel free to 
remove them as they are no longer used by any other ports, although note 
this is not currently the case, e.g.

Oberon ~ > port list depends:bazel-3.7
py37-dm-tree                   @0.1.5          python/py-dm-tree
py37-tensorflow                @2.6.0          python/py-tensorflow
py37-tensorflow-data-validation @0.28.0 
python/py-tensorflow-data-validation
py37-tensorflow-metadata       @0.29.0         python/py-tensorflow-metadata
py37-tensorflow-probability    @0.12.1 
python/py-tensorflow-probability
py37-tfx-bsl                   @0.28.1         python/py-tfx-bsl
py38-dm-tree                   @0.1.5          python/py-dm-tree
py38-tensorflow                @2.6.0          python/py-tensorflow
py38-tensorflow-data-validation @0.28.0 
python/py-tensorflow-data-validation
py38-tensorflow-metadata       @0.29.0         python/py-tensorflow-metadata
py38-tensorflow-probability    @0.12.1 
python/py-tensorflow-probability
py38-tfx-bsl                   @0.28.1         python/py-tfx-bsl
py39-dm-tree                   @0.1.5          python/py-dm-tree
py39-tensorflow                @2.6.0          python/py-tensorflow
py39-tensorflow-data-validation @0.28.0 
python/py-tensorflow-data-validation
py39-tensorflow-metadata       @0.29.0         python/py-tensorflow-metadata
py39-tensorflow-probability    @0.12.1 
python/py-tensorflow-probability
py39-tfx-bsl                   @0.28.1         python/py-tfx-bsl

you can try, but it might be those ports cannot just be moved to the 
latest bazel... The maximum allowed is usually a bit behind the most recent.

Chris

> 
> My takeaway is to avoid any version prior to version 5 (implying that the existing MacPorts bazel state is both broken and obsolete), and that only if absolutely necessary previous versions can be obtained from binary downloads from github.
> 
> Personally, I have also adopted the stance of avoiding bazel entirely unless absolutely necessary.
> 
>> On Jul 14, 2022, at 05:54, Chris Jones <jonesc at hep.phy.cam.ac.uk> wrote:
>>
>> Hi
>>
>>> On 13/07/2022 10:50 pm, Ryan Schmidt wrote:
>>>> On Jul 13, 2022, at 11:46, Steven Smith wrote:
>>>> How does one reconfigure the bazel Portfile to use a previous version of clang that has a chance of working to build previous versions of bazel, which are in turn necessary to build the tensor flow packages.
>>> If certain compilers that MacPorts might choose will not build a port, add their names to compiler.blacklist and MacPorts will choose another compiler.
>>> If you only want to exclude certain versions of a compiler (such as {clang < 700 >= 900}), include the compiler_blacklist_versions portgroup.
>>> If you've excluded all compilers MacPorts might choose, add a suitable compiler to compiler.fallback.
>>
>> This is all correct from the MacPorts side, but bazel is a different beast. It goes out of its way to not use the 'standard' ways of selecting compilers etc. That is why the bazel PG and portfile has all the convoluted logic it does to try and enforce the MP choice. I know this logic is fragile, it always has been.
>>
>> Personally, I've conceded defeat to bazel. I've lost interest in the battle but I wish you luck if you wish to take it up...
>>
>> Chris