I think I have figured out the problem.  I had a locally built and cached wheel of PyQt5-sip from before PEP573 went in.  If that wheel is used for later commits I get the segfault, if I rebuilt the wheel from source it works.

I am not sure if this is an expected sharp edge (wheels are be expected to be good between commits prior to a release) or not.


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Below is a script that will build everything (sip, pyqt5, pyqt5-sip) from source and install them into a virtual env.

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#! /usr/bin/bash
set -e
set -o xtrace



rm -r ~/.pybuild/py39 || true
pushd cpython
git clean -xfd
./configure --prefix=/home/tcaswell/.pybuild/py39
make -j 9
make install
popd

~/.pybuild/py39/bin/python3 -m venv --copies --clear ~/.virtualenvs/py39



source ~/.virtualenvs/py39/bin/activate
pip install --upgrade pip
echo $PATH

pushd PyQt5
pip install sip --no-binary sip
rm -rf PyQt5-5.14.2
tar -xzf PyQt5-5.14.2.tar.gz

pushd PyQt5-5.14.2
python configure.py --confirm-license
# patch the one palce that does not respect the venv settings
sed -i 's|$(INSTALL_ROOT)/usr|$(INSTALL_ROOT)/$(HOME)/.virtualenvs/py39/usr|g' Makefile
make -j 9
make install
popd
popd
pip install PyQt5-sip --no-binary PyQt5-sip

python -c "import PyQt5.QtCore; PyQt5.QtCore.Qt.Key_Control"


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