LazyImport.instancecheck, subclasscheck: Return False on ImportError #33017

mkoeppe · 2021-12-13T06:33:25Z

No object is an instance of a class that cannot be imported.

No class is a subclass of a class that cannot be imported.

Hence, we change LazyImport so that the special methods __instancecheck__, __subclasscheck__ catch ImportError and just return False.

(We do not use the stronger versions of these two statements: "No object is an instance of a class that has not been imported yet (i.e., the module name is not in sys.modules)." These are true only if there are no re-exports.)

With this change to LazyImport, we have another instrument for modularization of code that uses isinstance checks. (The use of isinstance with ABCs (#32566) is preferable because it avoids importing an otherwise unused implementation class.)

Depends on #32899

CC: @tscrim @kliem

Component: refactoring

Author: Matthias Koeppe

Branch: 7adef96

Reviewer: Jonathan Kliem

Issue created by migration from https://trac.sagemath.org/ticket/33017

The text was updated successfully, but these errors were encountered:

mkoeppe · 2021-12-13T06:44:15Z

Branch: u/mkoeppe/lazyimport___instancecheck______subclasscheck____return_false_on_importerror

mkoeppe · 2021-12-13T06:44:46Z

Author: Matthias Koeppe

mkoeppe · 2021-12-13T06:44:46Z

Commit: 447df69

mkoeppe · 2021-12-13T06:44:46Z

New commits:

`447df69`	`LazyImport.__instancecheck__, __subclasscheck__: Return False on ImportError`

kliem · 2021-12-13T09:35:14Z

comment:5

It's not fast I suspect, as it tries an import and fails every time. But it is correct at least.

kliem · 2021-12-13T09:35:22Z

Reviewer: Jonathan Kliem

mkoeppe · 2021-12-13T19:40:47Z

Dependencies: #32899

mkoeppe · 2021-12-13T20:28:56Z

comment:8

I'll add some documentation to discuss performance

sagetrac-git · 2021-12-14T00:17:46Z

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

`821d16e`	`src/doc/en/developer/packaging_sage_library.rst: Add bootstrap to testing instructions to avoid the trap of #32868`
`77c957f`	`src/doc/en/developer/packaging_sage_library.rst: Put hierarchy section one level higher`
`9375ef8`	`pkgs/sagemath-standard/tox.ini: Use SAGE_VENV or venv symlink to find wheels`
`c6fc111`	`Prettier diagram`
`7d6a44c`	`Use :mod: as markup for packages/modules`
`f83d424`	`Improve ABC example`
`817a8d0`	`src/doc/en/developer/packaging_sage_library.rst: More :mod: and :class: markup`
`b555735`	`src/doc/en/developer/packaging_sage_library.rst: Link to pypi.org and to documentation of packaging metadata`
`fb151ea`	`Merge #32899`
`907f8e8`	`src/doc/en/developer/packaging_sage_library.rst: Expand on LazyImport, add timings`

sagetrac-git · 2021-12-14T00:17:46Z

Changed commit from 447df69 to 907f8e8

kliem · 2021-12-15T14:42:33Z

comment:10

No patchbot yet, due to

https://groups.google.com/g/sage-devel/c/epajAbPvg6s/m/-yWW1gFyCAAJ

kliem · 2021-12-17T14:39:20Z

comment:11

Edited to remove unrelated failure.

$ sage -t --long --random-seed=57900501385357039198738698054253811820 src/doc/en/developer/packaging_sage_library.rst  # 8 doctests failed
too many failed tests, not using stored timings
Running doctests with ID 2021-12-17-15-38-43-8b38ad21.
Git branch: test_33017
Using --optional=4ti2,build,debian,dochtml,e_antic,latte_int,lidia,normaliz,pip,pynormaliz,sage,sage.geometry.polyhedron,sage.rings.real_double,sage_spkg
Doctesting 1 file.
sage -t --long --random-seed=57900501385357039198738698054253811820 src/doc/en/developer/packaging_sage_library.rst
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 285, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(object, pAdicFieldGeneric)            # fast                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[2]>", line 1
        %timeit isinstance(object, pAdicFieldGeneric)            # fast                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 289, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(object, sage.rings.abc.pAdicField)    # also fast                      # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[4]>", line 1
        %timeit isinstance(object, sage.rings.abc.pAdicField)    # also fast                      # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 311, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit is_Scheme_or_Pluffe(sZZ)                         # fast                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[3]>", line 1
        %timeit is_Scheme_or_Pluffe(sZZ)                         # fast                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 314, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit is_Scheme_or_Pluffe(ZZ)                          # slow                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[4]>", line 1
        %timeit is_Scheme_or_Pluffe(ZZ)                          # slow                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 323, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(sZZ, (Scheme, Pluffe))                # fast                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[1]>", line 1
        %timeit isinstance(sZZ, (Scheme, Pluffe))                # fast                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 326, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(ZZ, (Scheme, Pluffe))                 # slow                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[2]>", line 1
        %timeit isinstance(ZZ, (Scheme, Pluffe))                 # slow                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 340, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(sZZ, (Scheme, Pluffe))                # fast                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[1]>", line 1
        %timeit isinstance(sZZ, (Scheme, Pluffe))                # fast                           # random
        ^
    SyntaxError: invalid syntax
**********************************************************************
File "src/doc/en/developer/packaging_sage_library.rst", line 343, in doc.en.developer.packaging_sage_library
Failed example:
    %timeit isinstance(ZZ, (Scheme, Pluffe))                 # fast                           # random
Exception raised:
    Traceback (most recent call last):
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 694, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 1086, in compile_and_execute
        compiled = compiler(example)
      File "/srv/public/kliem/sage/local/var/lib/sage/venv-python3.7/lib/python3.7/site-packages/sage/doctest/forker.py", line 662, in compiler
        compileflags, 1)
      File "<doctest doc.en.developer.packaging_sage_library[2]>", line 1
        %timeit isinstance(ZZ, (Scheme, Pluffe))                 # fast                           # random
        ^
    SyntaxError: invalid syntax

sagetrac-git · 2021-12-17T18:13:55Z

Changed commit from 907f8e8 to 7adef96

sagetrac-git · 2021-12-17T18:13:55Z

Branch pushed to git repo; I updated commit sha1. New commits:

`7adef96`	`src/doc/en/developer/packaging_sage_library.rst: Mark %timeit # not tested`

kliem · 2022-04-08T19:42:01Z

comment:16

Sorry, I completely forgot about this. I think figured to wait on a patchbot.

You know, you can also ping me. I might not react, but I won't be annoyed.

mkoeppe · 2022-04-08T20:04:31Z

comment:17

Thanks! There was no urgency

vbraun · 2022-04-10T13:12:41Z

Changed branch from u/mkoeppe/lazyimport___instancecheck______subclasscheck____return_false_on_importerror to 7adef96

mkoeppe · 2022-04-10T16:40:16Z

Changed commit from 7adef96 to none

mkoeppe added this to the sage-9.5 milestone Dec 13, 2021

mkoeppe added t: refactoring labels Dec 13, 2021

mkoeppe added the s: needs review label Dec 13, 2021

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kliem added s: needs work and removed s: needs review labels Dec 17, 2021

mkoeppe added s: needs review and removed s: needs work labels Dec 17, 2021

mkoeppe modified the milestones: sage-9.5, sage-9.6 Dec 18, 2021

mkoeppe modified the milestones: sage-9.6, sage-9.7 Apr 2, 2022

kliem added s: positive review and removed s: needs review labels Apr 8, 2022

vbraun removed the s: positive review label Apr 10, 2022

vbraun closed this as completed in 204cbf0 Apr 10, 2022

mkoeppe modified the milestones: sage-9.7, sage-9.6 Apr 10, 2022

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LazyImport.instancecheck, subclasscheck: Return False on ImportError #33017

LazyImport.instancecheck, subclasscheck: Return False on ImportError #33017

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LazyImport.__instancecheck__, __subclasscheck__: Return False on ImportError #33017

LazyImport.__instancecheck__, __subclasscheck__: Return False on ImportError #33017

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LazyImport.instancecheck, subclasscheck: Return False on ImportError #33017

LazyImport.instancecheck, subclasscheck: Return False on ImportError #33017