hb_ft_font_get_ft_face error from CondaPkg installation

PythonPlot's src/init.jl から始め、生成された .CondaPkg/pixi.toml を使って最初のロードを再現します。matplotlib init.py の失敗と、その後に発生する Qt6Base_jll ライブラリエラーを比較し、依存関係のバージョンとレポートに示されたインストール出力を追跡します。完了条件は、新しい CondaPkg のインストール後に PythonPlot が正常にロードされることです。

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] <module>
   @ ~/.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.