Broken on Python 3.13.0

[MilesCranmer]

Importing juliacall on Python 3.13 (recently released) triggers the following error:

> import juliacall
---------------------------------------------------------------------------
SystemError                               Traceback (most recent call last)
SystemError: Type does not define the tp_name field.
ERROR: InitError: Error initializing 'juliacall.ValueBase'
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:35
  [2] init_c()
    @ PythonCall.JlWrap.Cjl ~/.julia/packages/PythonCall/Nr75f/src/JlWrap/C.jl:332
  [3] __init__()
    @ PythonCall.JlWrap.Cjl ~/.julia/packages/PythonCall/Nr75f/src/JlWrap/C.jl:337
  [4] run_module_init(mod::Module, i::Int64)
    @ Base ./loading.jl:1378
  [5] register_restored_modules(sv::Core.SimpleVector, pkg::Base.PkgId, path::String)
    @ Base ./loading.jl:1366
  [6] _include_from_serialized(pkg::Base.PkgId, path::String, ocachepath::String, depmods::Vector{Any}, ignore_native::Nothing; register::Bool)
    @ Base ./loading.jl:1254
  [7] _include_from_serialized (repeats 2 times)
    @ ./loading.jl:1210 [inlined]
  [8] _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:2057
  [9] _require(pkg::Base.PkgId, env::String)
    @ Base ./loading.jl:2527
 [10] __require_prelocked(uuidkey::Base.PkgId, env::String)
    @ Base ./loading.jl:2388
 [11] #invoke_in_world#3
    @ ./essentials.jl:1089 [inlined]
 [12] invoke_in_world
    @ ./essentials.jl:1086 [inlined]
 [13] _require_prelocked(uuidkey::Base.PkgId, env::String)
    @ Base ./loading.jl:2375
 [14] macro expansion
    @ ./loading.jl:2314 [inlined]
 [15] macro expansion
    @ ./lock.jl:273 [inlined]
 [16] __require(into::Module, mod::Symbol)
    @ Base ./loading.jl:2271
 [17] #invoke_in_world#3
    @ ./essentials.jl:1089 [inlined]
 [18] invoke_in_world
    @ ./essentials.jl:1086 [inlined]
 [19] require(into::Module, mod::Symbol)
    @ Base ./loading.jl:2260
 [20] top-level scope
    @ none:8
during initialization of module Cjl---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
Cell In[1], line 1
----> 1 import juliacall

File ~/PermaDocuments/PythonCall.jl/pysrc/juliacall/__init__.py:287
    284     import juliacall.ipython
    285     juliacall.ipython.load_ipython_extension(ip)
--> 287 init()

File ~/PermaDocuments/PythonCall.jl/pysrc/juliacall/__init__.py:239, in init()
    237 res = jl_eval(script.encode('utf8'))
    238 if res is None:
--> 239     raise Exception('PythonCall.jl did not start properly')
    241 CONFIG['inited'] = True
    243 if CONFIG['opt_handle_signals'] is None:

Exception: PythonCall.jl did not start properly

It looks to be from this tp_name thing? https://peps.python.org/pep-0737/

cc @cjdoris @mkitti

[MilesCranmer]

Wait, weird! 3.13.1 of Python is actually working. My error above is with 3.13.0.

I wonder if they made a backwards incompatible change to the C API and then reverted it? Sorry for the spam.