`lib("freegb.lib")` sometimes make Conda build crash

[user202729]

Steps To Reproduce

e.g.

https://github.com/sagemath/sage/actions/runs/12227176866/job/34103526826?pr=37447#step:9:7618

Expected Behavior

Actual Behavior

Additional Information

No response

Environment

• OS: Conda on Ubuntu
• Sage Version: 3.11

Checklist

• I have searched the existing issues for a bug report that matches the one I want to file, without success.
• I have read the documentation and troubleshoot guide

[tobiasdiez]

For reference (the build log will disappear in 2 months):

sage -t --warn-long 5.0 --random-seed=85049595565619788885733902960031249362 src/sage/rings/polynomial/plural.pyx
    SignalError in doctesting framework
**********************************************************************

Tests run before exception:
sage: A.<x,y,z> = FreeAlgebra(QQ, 3) ## line 50 ##
sage: P.<x,y,z> = A.g_algebra(relations={y*x:-x*y}, order = 'lex') ## line 51 ##
sage: P ## line 53 ##
Noncommutative Multivariate Polynomial Ring in x, y, z over Rational Field, nc-relations: {y*x: -x*y}
sage: y*x + 1/2 ## line 56 ##
-x*y + 1/2
sage: A.<x,y,z> = FreeAlgebra(GF(17), 3) ## line 59 ##
sage: P.<x,y,z> = A.g_algebra(relations={y*x:-x*y}, order = 'lex') ## line 60 ##
sage: P ## line 61 ##
Noncommutative Multivariate Polynomial Ring in x, y, z over Finite Field of size 17, nc-relations: {y*x: -x*y}
sage: y*x + 7 ## line 64 ##
-x*y + 7
sage: from sage.matrix.constructor import Matrix ## line 71 ##
sage: c = Matrix(3) ## line 72 ##
sage: c[0,1] = -2 ## line 73 ##
sage: c[0,2] = 1 ## line 74 ##
sage: c[1,2] = 1 ## line 75 ##
sage: d = Matrix(3) ## line 77 ##
sage: d[0, 1] = 17 ## line 78 ##
sage: P = QQ['x','y','z'] ## line 79 ##
sage: c = c.change_ring(P) ## line 80 ##
sage: d = d.change_ring(P) ## line 81 ##
sage: from sage.rings.polynomial.plural import NCPolynomialRing_plural ## line 83 ##
sage: R.<x,y,z> = NCPolynomialRing_plural(QQ, c = c, d = d, order=TermOrder('lex',3),category=Algebras(QQ)) ## line 84 ##
sage: R ## line 85 ##
Noncommutative Multivariate Polynomial Ring in x, y, z over Rational Field, nc-relations: {y*x: -2*x*y + 17}
sage: R.term_order() ## line 88 ##
Lexicographic term order
sage: a,b,c = R.gens() ## line 91 ##
sage: f = 57 * a^2*b + 43 * c + 1; f ## line 92 ##
57*x^2*y + 43*z + 1
sage: A.<x,y,z> = FreeAlgebra(QQ, 3) ## line 97 ##
sage: P = A.g_algebra(relations={y*x:-x*y}, order = 'lex') ## line 98 ##
sage: TestSuite(P).run() ## line 99 ##
sage: loads(dumps(P)) is P ## line 100 ##
True
sage: A.<x,y,z> = FreeAlgebra(QQ, 3) ## line 103 ##
sage: P = A.g_algebra(relations={y*x:-x*y}, order = 'lex') ## line 104 ##
sage: P.is_commutative() ## line 105 ##
False
sage: R.<x,y,z> = FreeAlgebra(QQ, 3) ## line 108 ##
sage: P = R.g_algebra(relations={}, order='lex') ## line 109 ##
sage: P.is_commutative() ## line 110 ##
True
sage: sig_on_count() # check sig_on/off pairings (virtual doctest) ## line 112 ##
0
sage: A.<x,y,z> = FreeAlgebra(QQ, 3) ## line 156 ##
sage: H = A.g_algebra({y*x:x*y-z, z*x:x*z+2*x, z*y:y*z-2*y}) ## line 157 ##

**********************************************************************
Traceback (most recent call last):
  File "parent.pyx", line 895, in sage.structure.parent.Parent.__call__
  File "coerce_dict.pyx", line 650, in sage.structure.coerce_dict.MonoDict.get
KeyError: Free Algebra on 3 generators (x, y, z) over Rational Field

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "parent.pyx", line 2501, in sage.structure.parent.Parent._internal_convert_map_from
  File "coerce_dict.pyx", line 650, in sage.structure.coerce_dict.MonoDict.get
KeyError: Free Algebra on 3 generators (x, y, z) over Rational Field

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/doctest/forker.py", line 2596, in __call__
    doctests, extras = self._run(runner, options, results)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/doctest/forker.py", line 2644, in _run
    result = runner.run(test)
             ^^^^^^^^^^^^^^^^
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/doctest/forker.py", line 905, in run
    return self._run(test, compileflags, out)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/doctest/forker.py", line 716, in _run
    self.compile_and_execute(example, compiler, test.globs)
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/doctest/forker.py", line 1137, in compile_and_execute
    exec(compiled, globs)
  File "<doctest sage.rings.polynomial.plural.G_AlgFactory[1]>", line 1, in <module>
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/algebras/free_algebra.py", line 1018, in g_algebra
    dmat[v2_ind, v1_ind] = polynomial_ring(d_poly)
                           ^^^^^^^^^^^^^^^^^^^^^^^
  File "parent.pyx", line 897, in sage.structure.parent.Parent.__call__
  File "parent.pyx", line 2503, in sage.structure.parent.Parent._internal_convert_map_from
  File "parent.pyx", line 2524, in sage.structure.parent.Parent.discover_convert_map_from
  File "parent.pyx", line 2146, in sage.structure.parent.Parent._internal_coerce_map_from
  File "parent.pyx", line 2238, in sage.structure.parent.Parent._internal_coerce_map_from
  File "parent.pyx", line 2383, in sage.structure.parent.Parent.discover_coerce_map_from
  File "module.pyx", line 132, in sage.modules.module.Module._coerce_map_from_
  File "/usr/share/miniconda3/envs/sage-dev/lib/python3.11/site-packages/sage/algebras/free_algebra.py", line 771, in _coerce_map_from_
    if isinstance(R, (FreeAlgebra_generic, FreeAlgebra_letterplace)):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "lazy_import.pyx", line 966, in sage.misc.lazy_import.LazyImport.__instancecheck__
  File "lazy_import.pyx", line 224, in sage.misc.lazy_import.LazyImport.get_object
  File "lazy_import.pyx", line 259, in sage.misc.lazy_import.LazyImport._get_object
  File "free_algebra_letterplace.pyx", line 1, in init sage.algebras.letterplace.free_algebra_letterplace
  File "free_algebra_element_letterplace.pyx", line 25, in init sage.algebras.letterplace.free_algebra_element_letterplace
  File "function.pyx", line 1812, in sage.libs.singular.function.lib
cysignals.signals.SignalError: Segmentation fault

[user202729]

Technically I think the bug isn't that rare so maybe there's a way to just grep through all the logs of this particular type.

… I haven't looked up whether GitHub actions have programmatic API to access it like that yet.

[tobiasdiez]

Technically I think the bug isn't that rare so maybe there's a way to just grep through all the logs of this particular type.

… I haven't looked up whether GitHub actions have programmatic API to access it like that yet.

Have a look at #39100 if you would like to pursue this idea further.

[user202729]

Curious case (normally it's outright segmentation fault, but in this case the sig_on catches it somehow)

2025-01-22T10:44:16.3718880Z **********************************************************************
2025-01-22T10:44:16.3834580Z File "src/sage/rings/polynomial/plural.pyx", line 157, in sage.rings.polynomial.plural.G_AlgFactory
2025-01-22T10:44:16.3934590Z Failed example:
2025-01-22T10:44:16.4034990Z     H = A.g_algebra({y*x:x*y-z, z*x:x*z+2*x, z*y:y*z-2*y})
2025-01-22T10:44:16.4135730Z Exception raised:
2025-01-22T10:44:16.4236560Z     Traceback (most recent call last):
2025-01-22T10:44:16.4337020Z       File "sage/structure/parent.pyx", line 895, in sage.structure.parent.Parent.__call__
2025-01-22T10:44:16.4437520Z         mor = <map.Map> self._convert_from_hash.get(R)
2025-01-22T10:44:16.4538680Z       File "sage/structure/coerce_dict.pyx", line 650, in sage.structure.coerce_dict.MonoDict.get
2025-01-22T10:44:16.4639770Z         raise KeyError(k)
2025-01-22T10:44:16.4740970Z     KeyError: Free Algebra on 3 generators (x, y, z) over Rational Field
2025-01-22T10:44:16.4860600Z 
2025-01-22T10:44:16.4967970Z     During handling of the above exception, another exception occurred:
2025-01-22T10:44:16.5068830Z 
2025-01-22T10:44:16.5169710Z     Traceback (most recent call last):
2025-01-22T10:44:16.5270940Z       File "sage/structure/parent.pyx", line 2501, in sage.structure.parent.Parent._internal_convert_map_from
2025-01-22T10:44:16.5372970Z         return self._convert_from_hash.get(S)
2025-01-22T10:44:16.5483650Z       File "sage/structure/coerce_dict.pyx", line 650, in sage.structure.coerce_dict.MonoDict.get
2025-01-22T10:44:16.5598940Z         raise KeyError(k)
2025-01-22T10:44:16.5706340Z     KeyError: Free Algebra on 3 generators (x, y, z) over Rational Field
2025-01-22T10:44:16.5806940Z 
2025-01-22T10:44:16.5922470Z     During handling of the above exception, another exception occurred:
2025-01-22T10:44:16.6043680Z 
2025-01-22T10:44:16.6144550Z     Traceback (most recent call last):
2025-01-22T10:44:16.6245730Z       File "/Users/runner/work/sage/sage/src/sage/doctest/forker.py", line 728, in _run
2025-01-22T10:44:16.6346890Z         self.compile_and_execute(example, compiler, test.globs)
2025-01-22T10:44:16.6447940Z       File "/Users/runner/work/sage/sage/src/sage/doctest/forker.py", line 1152, in compile_and_execute
2025-01-22T10:44:16.6548970Z         exec(compiled, globs)
2025-01-22T10:44:16.6658410Z       File "<doctest sage.rings.polynomial.plural.G_AlgFactory[1]>", line 1, in <module>
2025-01-22T10:44:16.6764860Z         H = A.g_algebra({y*x:x*y-z, z*x:x*z+Integer(2)*x, z*y:y*z-Integer(2)*y})
2025-01-22T10:44:16.6866090Z             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2025-01-22T10:44:16.6967470Z       File "/Users/runner/work/sage/sage/src/sage/algebras/free_algebra.py", line 1018, in g_algebra
2025-01-22T10:44:16.7067760Z         dmat[v2_ind, v1_ind] = polynomial_ring(d_poly)
2025-01-22T10:44:16.7169250Z                                ^^^^^^^^^^^^^^^^^^^^^^^
2025-01-22T10:44:16.7271390Z       File "sage/structure/parent.pyx", line 897, in sage.structure.parent.Parent.__call__
2025-01-22T10:44:16.7370990Z         mor = <map.Map> self._internal_convert_map_from(R)
2025-01-22T10:44:16.7472930Z       File "sage/structure/parent.pyx", line 2503, in sage.structure.parent.Parent._internal_convert_map_from
2025-01-22T10:44:16.7574290Z         mor = self.discover_convert_map_from(S)
2025-01-22T10:44:16.7674790Z       File "sage/structure/parent.pyx", line 2524, in sage.structure.parent.Parent.discover_convert_map_from
2025-01-22T10:44:16.7775710Z         mor = S._internal_coerce_map_from(self)
2025-01-22T10:44:16.7876200Z       File "sage/structure/parent.pyx", line 2146, in sage.structure.parent.Parent._internal_coerce_map_from
2025-01-22T10:44:16.7977380Z         cpdef _internal_coerce_map_from(self, S):
2025-01-22T10:44:16.8078000Z       File "sage/structure/parent.pyx", line 2238, in sage.structure.parent.Parent._internal_coerce_map_from
2025-01-22T10:44:16.8193860Z         mor = self.discover_coerce_map_from(S)
2025-01-22T10:44:16.8300530Z       File "sage/structure/parent.pyx", line 2383, in sage.structure.parent.Parent.discover_coerce_map_from
2025-01-22T10:44:16.8401260Z         user_provided_mor = self._coerce_map_from_(S)
2025-01-22T10:44:16.8503160Z       File "sage/modules/module.pyx", line 132, in sage.modules.module.Module._coerce_map_from_
2025-01-22T10:44:16.8603510Z         cpdef _coerce_map_from_(self, M):
2025-01-22T10:44:16.8716200Z       File "/Users/runner/work/sage/sage/src/sage/algebras/free_algebra.py", line 771, in _coerce_map_from_
2025-01-22T10:44:16.8849400Z         if isinstance(R, (FreeAlgebra_generic, FreeAlgebra_letterplace)):
2025-01-22T10:44:16.8977760Z            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2025-01-22T10:44:16.9080400Z       File "sage/misc/lazy_import.pyx", line 966, in sage.misc.lazy_import.LazyImport.__instancecheck__
2025-01-22T10:44:16.9181390Z         return isinstance(x, self.get_object())
2025-01-22T10:44:16.9309310Z       File "sage/misc/lazy_import.pyx", line 224, in sage.misc.lazy_import.LazyImport.get_object
2025-01-22T10:44:16.9422700Z         return self._get_object()
2025-01-22T10:44:16.9525060Z       File "sage/misc/lazy_import.pyx", line 259, in sage.misc.lazy_import.LazyImport._get_object
2025-01-22T10:44:16.9638130Z         self._object = getattr(__import__(self._module, {}, {}, [self._name]), self._name)
2025-01-22T10:44:16.9738990Z       File "sage/algebras/letterplace/free_algebra_letterplace.pyx", line 1, in init sage.algebras.letterplace.free_algebra_letterplace
2025-01-22T10:44:16.9839630Z         ###############################################################################
2025-01-22T10:44:16.9940940Z       File "sage/algebras/letterplace/free_algebra_element_letterplace.pyx", line 25, in init sage.algebras.letterplace.free_algebra_element_letterplace
2025-01-22T10:44:17.0041960Z         lib("freegb.lib")
2025-01-22T10:44:17.0142850Z       File "sage/libs/singular/function.pyx", line 1805, in sage.libs.singular.function.lib
2025-01-22T10:44:17.0249160Z         sig_on()
2025-01-22T10:44:17.0350490Z     RuntimeError: Aborted
2025-01-22T10:44:17.0451490Z **********************************************************************

From #39142 but it's probably unrelated.

[user202729]

I found an undefined behavior there…

• in cython, bint is int: https://cython.readthedocs.io/en/latest/src/userguide/language_basics.html
• in singular, BOOLEAN is char: typedef char BOOLEAN;

maybe on Mac the calling convention is different between these 2 types to cause a segmentation fault. (on x86 it looks harmless.)

EDIT: actually it's unrelated… the generated C code doesn't include the function declaration at all.

There's a memory leak there though, because the function doesn't consume the string so the omStrDup is actually redundant.

[user202729]

Duplicate of #29528 or #38737

There's some discussion there — maybe it's because the singular polynomial rings are not garbage collected, though I can't see why it's relevant.