On Tuesday, April 23, 2024 at 11:06:12 AM UTC-7 Dima Pasechnik wrote:
On 23 April 2024 18:41:34 BST, Matthias Koeppe <matthia...@gmail.com>
wrote:
>*$ git blame src/sage/combinat//designs/block_design.py*
>
>fdbe7f7e3348 (Matthias Koeppe 2023-07-12 10:53:08 -0700 65)
>lazy_import('sage.libs.gap.libgap', 'libgap')
>fdbe7f7e3348 (Matthias Koeppe 2023-07-12 10:53:08 -0700 66)
>lazy_import('sage.matrix.matrix_space', 'MatrixSpace')
>fdbe7f7e3348 (Matthias Koeppe 2023-07-12 10:53:08 -0700 67)
>lazy_import('sage.modules.free_module', 'VectorSpace')
>fdbe7f7e3348 (Matthias Koeppe 2023-07-12 10:53:08 -0700 68)
>lazy_import('sage.rings.finite_rings.finite_field_constructor',
>'FiniteField')
>
>What you see there is the result of work in the modularization project,
>using one of the techniques documented
>in
https://doc.sagemath.org/html/en/developer/packaging_sage_library.html#dependencies-and-distribution-packages
>("Reducing module-level run-time dependencies:") to reduce dependencies or
>to make dependencies milder.
The problem is that without these imports, lazy or not, this module is
basically useless.
That's correct, but that's not a "problem".
It's part of a deliberate design, explained in detail in my 2023-06
sage-devel posts.
>From "*Modularization project: IV. The rules*"
(https://groups.google.com/g/sage-devel/c/ozh-7ZZ848s):
*3.* Distribution packages declare build dependencies and runtime
dependencies
<https://sagemath-tobias.netlify.app/developer/packaging_sage_library.html#dependencies-and-distribution-packages>
(on
other Python distribution packages). These two can be entirely unrelated to
each other. In addition to the runtime dependencies, it is possible to
declare extra dependencies – either those necessary for running tests
<https://sagemath-tobias.netlify.app/developer/packaging_sage_library.html#doctest-only-dependencies>
or
for providing advertised
<https://sagemath-tobias.netlify.app/developer/packaging_sage_library.html#other-runtime-dependencies>
extra
<https://sagemath-tobias.netlify.app/developer/packaging_sage_library.html#other-runtime-dependencies>
features
<https://sagemath-tobias.netlify.app/developer/packaging_sage_library.html#other-runtime-dependencies>.
But there is no such thing as an "optional build dependency" or
"conditional compilation". The set of modules that form a distribution
package is static. There is no place in the name (or metadata) of a wheel
package that could indicate different "configurations".
*4. *As a result of 3, it is possible to create distributions that contain
some modules that cannot be imported because some of their dependencies are
missing. That's OK; they can become importable simply by the presence of
other distributions, in particular those declared as extra dependencies.
All of this is discovered at the time of importing a module; there is no
ahead-of-time linking step of any sort.
>From "*Modularization project: V. The blocs*"
(https://groups.google.com/g/sage-devel/c/kiB32zP3xD4):
*We should not attempt to define a distribution package for every possible
community or subfield of mathematics that Sage supports.*
The proposed design instead introduces 3 types of distribution packages:
[...]
Each of the distribution packages can define a list of extras (nicknames
for sets of other distribution packages that provide additional advertised
features). When using pip to install a distribution, users can use square
bracket notation to add (adjoin?) these extras.
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