has_gens errors because generators are not known #5661
Description
Describe the bug
has_gens sometimes throws an Error if gnerators are not known instead of returning false
To Reproduce
julia> s = SL(5, QQ)
SL(5,QQ)
julia> has_gens(s)
ERROR: no generators are known for the matrix group of type SL over Rational field
Stacktrace:
[1] error(s::String)
@ Base ./error.jl:44
[2] assign_from_description(G::MatrixGroup{QQFieldElem, QQMatrix})
@ Oscar ~/.julia/packages/Oscar/eTXAp/src/Groups/matrices/MatGrp.jl:245
[3] GapObj_internal(G::MatrixGroup{QQFieldElem, QQMatrix}, cache::Nothing, ::Val{false})
@ Oscar ~/.julia/packages/Oscar/eTXAp/src/Groups/matrices/MatGrp.jl:315
[4] GapObj(x::MatrixGroup{QQFieldElem, QQMatrix}; recursive::Bool)
@ GAP ~/.julia/packages/GAP/4O4Af/src/julia_to_gap.jl:79
[5] GapObj
@ ~/.julia/packages/GAP/4O4Af/src/julia_to_gap.jl:79 [inlined]
[6] has_gens(G::MatrixGroup{QQFieldElem, QQMatrix})
@ Oscar ~/.julia/packages/Oscar/eTXAp/src/Groups/GAPGroups.jl:642
[7] top-level scope
@ REPL[5]:1
Expected behavior
return false
System (please complete the following information):
Please paste the output of Oscar.versioninfo(full=true) below. If this does
not work, please paste the output of Julia's versioninfo() and your Oscar
version.
julia> Oscar.versioninfo(full=true)
OSCAR version 1.6.0
combining:
AbstractAlgebra.jl v0.47.6
GAP.jl v0.16.2
Hecke.jl v0.39.3
Nemo.jl v0.52.4
Polymake.jl v0.13.4
Singular.jl v0.28.2
building on:
FLINT_jll v301.300.102+0
GAP_jll v400.1500.100+1
GAP_lib_jll v400.1500.100+0
Singular_jll v404.101.502+0
libpolymake_julia_jll v0.14.3+1
libsingular_julia_jll v0.47.9+0
polymake_jll v400.1500.0+0
polymake_oscarnumber_jll v0.3.12+1
See `]st -m` for a full list of dependencies.
Julia Version 1.12.3
Commit 966d0af0fdf (2025-12-15 11:20 UTC)
Build Info:
Official https://julialang.org release
Platform Info:
OS: Linux (x86_64-linux-gnu)
CPU: 16 × AMD Ryzen 7 5825U with Radeon Graphics
WORD_SIZE: 64
LLVM: libLLVM-18.1.7 (ORCJIT, znver3)
GC: Built with stock GC
Threads: 1 default, 1 interactive, 1 GC (on 16 virtual cores)
Environment:
JULIA_EDITOR = code
Official https://julialang.org release