[Workflow Interface]: Prints on running a flow with ray backend are coming in a previous notebook cell

[scngupta-dsp]

Issue Description:
When using backend=ray, the prints on executing flflow.run are appearing in a previous notebook cell. This is quite strange and inconvenient to user

To Reproduce:
Run openfl-tutorials/experimental/workflow/102_Aggregator_Validation.ipynb

Logs: Refer snapshot below

Desktop:

• OS: Ubuntu (WSL)
• OS Version: 22.04.3 LTS
• Python: 3.11

Versions:

aiosignal 1.3.2
ansicolors 1.1.8
astroid 3.3.8
asttokens 3.0.0
astunparse 1.6.3
attrs 25.1.0
bcrypt 4.3.0
boto3 1.37.3
botocore 1.37.3
certifi 2025.1.31
cffi 1.17.1
chardet 5.2.0
charset-normalizer 3.4.1
click 8.1.8
cloudpickle 3.1.1
comm 0.2.2
contourpy 1.3.1
cryptography 44.0.1
cycler 0.12.1
debugpy 1.8.12
decorator 5.2.1
defusedxml 0.7.1
dill 0.3.6
docker 7.1.0
dynaconf 3.2.10
entrypoints 0.4
exceptiongroup 1.2.2
execnb 0.1.11
executing 2.2.0
fastcore 1.7.29
fastjsonschema 2.21.1
filelock 3.17.0
flatten-json 0.1.14
fonttools 4.56.0
fpdf 1.7.2
frozenlist 1.5.0
fsspec 2025.2.0
ghapi 1.0.6
grpcio 1.65.5
idna 3.10
importlib_metadata 8.6.1
iniconfig 2.0.0
ipykernel 6.29.5
ipython 8.32.0
ipywidgets 8.1.5
isort 6.0.1
jedi 0.19.2
Jinja2 3.1.5
jmespath 1.0.1
joblib 1.4.2
jsonschema 4.23.0
jsonschema-specifications 2024.10.1
jupyter_client 8.6.3
jupyter_core 5.7.2
jupyterlab_widgets 3.0.13
kiwisolver 1.4.8
lxml 5.3.1
markdown-it-py 3.0.0
MarkupSafe 3.0.2
matplotlib 3.10.0
matplotlib-inline 0.1.7
mccabe 0.7.0
mdurl 0.1.2
metaflow 2.7.15
mpmath 1.3.0
msgpack 1.1.0
nbclient 0.10.2
nbdev 2.3.12
nbformat 5.10.4
nest_asyncio 1.6.0
networkx 3.4.2
numpy 2.2.3
nvidia-cublas-cu12 12.1.3.1
nvidia-cuda-cupti-cu12 12.1.105
nvidia-cuda-nvrtc-cu12 12.1.105
nvidia-cuda-runtime-cu12 12.1.105
nvidia-cudnn-cu12 8.9.2.26
nvidia-cufft-cu12 11.0.2.54
nvidia-curand-cu12 10.3.2.106
nvidia-cusolver-cu12 11.4.5.107
nvidia-cusparse-cu12 12.1.0.106
nvidia-nccl-cu12 2.20.5
nvidia-nvjitlink-cu12 12.8.61
nvidia-nvtx-cu12 12.1.105
openfl 1.8.0.dev0
packaging 24.2
pandas 2.2.3
papermill 2.6.0
paramiko 3.5.1
parso 0.8.4
pexpect 4.9.0
pickleshare 0.7.5
pillow 11.1.0
pip 25.0.1
platformdirs 4.3.6
pluggy 1.5.0
prompt_toolkit 3.0.50
protobuf 5.29.3
psutil 7.0.0
ptyprocess 0.7.0
pure_eval 0.2.3
pycparser 2.22
pycryptodome 3.21.0
Pygments 2.19.1
pylint 3.3.4
PyNaCl 1.5.0
pyparsing 3.2.1
pytest 8.3.4
pytest-asyncio 0.25.3
pytest-mock 3.14.0
python-dateutil 2.9.0.post0
pytz 2025.1
PyYAML 6.0.2
pyzmq 26.2.1
ray 2.9.2
referencing 0.36.2
requests 2.32.3
rich 13.9.4
rpds-py 0.23.1
s3transfer 0.11.3
scikit-learn 1.6.1
scipy 1.15.2
setuptools 75.8.2
six 1.17.0
stack_data 0.6.3
sympy 1.13.3
tabulate 0.9.0
tenacity 9.0.0
tensorboardX 2.6.2.2
threadpoolctl 3.5.0
tomlkit 0.13.2
torch 2.3.1
torchvision 0.18.1
tornado 6.4.2
tqdm 4.67.1
traitlets 5.14.3
triton 2.3.1
typing_extensions 4.12.2
tzdata 2025.1
urllib3 2.3.0
watchdog 6.0.0
wcwidth 0.2.13
wheel 0.45.1
widgetsnbextension 4.0.13
zipp 3.21.0

[scngupta-dsp]

Able to reproduce this issue with a minimal example - logs below. From this snapshot we can see

• The logs from a ray future are being printed in the cell where ray was initialized
• This is the same behavior observed in Workflow Interface tutorial where the logs are printed in the cell where LocalRuntime is instantiated

[scngupta-dsp]

Additional Information:
Issue is not observed after downgrading ipykernel to 6.26.0. Reference issue logged: ipython/ipykernel#1370