hb_ft_font_get_ft_face error from CondaPkg installation

On a fresh install of julia and `PythonPlot` i get the following error when trying to load it:
```
CondaPkg Found dependencies: /home/anton/.julia/packages/CondaPkg/lKlVY/CondaPkg.toml
CondaPkg Found dependencies: /home/anton/.julia/packages/PythonCall/5WGSP/CondaPkg.toml
CondaPkg Found dependencies: /home/anton/.julia/packages/PythonPlot/oS8x4/CondaPkg.toml
CondaPkg Resolving changes
+ libstdcxx
+ libstdcxx-ng
+ matplotlib
+ openssl
+ python
CondaPkg Initialising pixi
│ /home/anton/.julia/artifacts/4ae17cee0bd922f66b2c72bf2f01c22481a5ec19/bin/pixi
│ init
│ --format pixi
└ /home/anton/.julia/environments/v1.12/.CondaPkg
✔ Created /home/anton/.julia/environments/v1.12/.CondaPkg/pixi.toml
CondaPkg Wrote /home/anton/.julia/environments/v1.12/.CondaPkg/pixi.toml
│ [dependencies]
│ openssl = ">=3, <3.6"
│ libstdcxx = ">=3.4,<15.0"
│ libstdcxx-ng = ">=3.4,<15.0"
│ matplotlib = ">=1"
│
│ [dependencies.python]
│ channel = "conda-forge"
│ build = "*cp*"
│ version = ">=3.10,!=3.14.0,!=3.14.1,<4"
│
│ [workspace]
│ name = ".CondaPkg"
│ platforms = ["linux-64"]
│ channels = ["conda-forge"]
│ channel-priority = "strict"
└ description = "automatically generated by CondaPkg.jl"
CondaPkg Installing packages
│ /home/anton/.julia/artifacts/4ae17cee0bd922f66b2c72bf2f01c22481a5ec19/bin/pixi
│ install
└ --manifest-path /home/anton/.julia/environments/v1.12/.CondaPkg/pixi.toml
✔ The default environment has been installed.
ERROR: LoadError: InitError: Python: ImportError: /home/anton/.julia/environments/v1.12/.CondaPkg/.pixi/envs/default/lib/python3.14/site-packages/matplotlib/../../../libraqm.so.0: undefined symbol: hb_ft_font_get_ft_face
Python stacktrace:
[1] _check_versions
@ ~/.julia/environments/v1.12/.CondaPkg/.pixi/envs/default/lib/python3.14/site-packages/matplotlib/__init__.py:250
[2]
@ ~/.julia/environments/v1.12/.CondaPkg/.pixi/envs/default/lib/python3.14/site-packages/matplotlib/__init__.py:265
during initialization of module PythonPlot
in expression starting at /home/anton/syscop/software/CCOptExperiments.jl/scripts/common.jl:10
Stacktrace:
[1] pythrow()
@ PythonCall.Core ~/.julia/packages/PythonCall/5WGSP/src/Core/err.jl:77
[2] errcheck
@ ~/.julia/packages/PythonCall/5WGSP/src/Core/err.jl:10 [inlined]
[3] pyimport
@ ~/.julia/packages/PythonCall/5WGSP/src/Core/builtins.jl:1474 [inlined]
[4] __init__()
@ PythonPlot ~/.julia/packages/PythonPlot/oS8x4/src/init.jl:150
[5] run_module_init(mod::Module, i::Int64)
@ Base ./loading.jl:1443
[6] register_restored_modules(sv::Core.SimpleVector, pkg::Base.PkgId, path::String)
@ Base ./loading.jl:1431
[7] _include_from_serialized(pkg::Base.PkgId, path::String, ocachepath::String, depmods::Vector{Any}; register::Bool)
@ Base ./loading.jl:1319
[8] _include_from_serialized
@ ./loading.jl:1274 [inlined]
[9] _require_search_from_serialized(pkg::Base.PkgId, sourcepath::String, build_id::UInt128, stalecheck::Bool; reasons::Dict{String, Int64}, DEPOT_PATH::Vector{String})
@ Base ./loading.jl:2115
[10] _require_search_from_serialized
@ ./loading.jl:2009 [inlined]
[11] __require_prelocked(pkg::Base.PkgId, env::String)
@ Base ./loading.jl:2627
[12] _require_prelocked(uuidkey::Base.PkgId, env::String)
@ Base ./loading.jl:2493
[13] macro expansion
@ ./loading.jl:2421 [inlined]
[14] macro expansion
@ ./lock.jl:376 [inlined]
[15] __require(into::Module, mod::Symbol)
@ Base ./loading.jl:2386
[16] require(into::Module, mod::Symbol)
@ Base ./loading.jl:2362
[17] eval(m::Module, e::Any)
@ Core ./boot.jl:489
[18] include_string(mapexpr::typeof(identity), mod::Module, code::String, filename::String)
@ Base ./loading.jl:2870
[19] _include(mapexpr::Function, mod::Module, _path::String)
@ Base ./loading.jl:2930
[20] include(mapexpr::Function, mod::Module, _path::String)
@ Base ./Base.jl:307
[21] (::Base.IncludeInto)(fname::String)
@ Base ./Base.jl:308
[22] top-level scope
@ ~/syscop/software/CCOptExperiments.jl/scripts/macmpec/run_macmpec.jl:1
in expression starting at /home/anton/syscop/software/CCOptExperiments.jl/scripts/macmpec/run_macmpec.jl:1
```

The second time I try to use PythonPlot I get the following:
```
ERROR: LoadError: InitError: could not load library "/home/anton/.julia/artifacts/48d95e60ccfecd4622b42d4fbeda49b2cbc7530b/lib/libQt6DBus.so"
/home/anton/.julia/artifacts/48d95e60ccfecd4622b42d4fbeda49b2cbc7530b/lib/libQt6DBus.so: undefined symbol: _ZN14QObjectPrivateC2E16QtPrivate_6_10_2, version Qt_6_PRIVATE_API
during initialization of module Qt6Base_jll
```

Which seems to be something broken in the Yggdrasil build of the Qt6Base jll package.

I haven't a clue where to even start debugging this as I am _not_ a conda (pixi, etc) user and this seems like an issue with that side.

Start with PythonPlot's src/init.jl and reproduce the first load using the generated .CondaPkg/pixi.toml. Compare the matplotlib __init__.py failure with the later Qt6Base_jll library error, tracing the dependency versions and installation output shown in the report. Done means PythonPlot loads successfully after a fresh CondaPkg installation.

Rédigé par le modèle d'indexation à partir du texte de l'issue.