More debug printing

IPython/external/qt_for_kernel.py

@@ -1,136 +1,137 b''
 """ Import Qt in a manner suitable for an IPython kernel.
 
 This is the import used for the `gui=qt` or `matplotlib=qt` initialization.
 
 Import Priority:
 
 if Qt has been imported anywhere else:
    use that
 
 if matplotlib has been imported and doesn't support v2 (<= 1.0.1):
     use PyQt4 @v1
 
 Next, ask QT_API env variable
 
 if QT_API not set:
     ask matplotlib what it's using. If Qt4Agg or Qt5Agg, then use the
         version matplotlib is configured with
 
     else: (matplotlib said nothing)
         # this is the default path - nobody told us anything
         try in this order:
             PyQt default version, PySide, PyQt5
 else:
     use what QT_API says
 
     Note that %gui's implementation will always set a `QT_API`, see
     `IPython.terminal.pt_inputhooks.get_inputhook_name_and_func`
 
 """
 # NOTE: This is no longer an external, third-party module, and should be
 # considered part of IPython. For compatibility however, it is being kept in
 # IPython/external.
 
 import os
 import sys
 
 from IPython.external.qt_loaders import (
     load_qt,
     loaded_api,
     enum_factory,
     # QT6
     QT_API_PYQT6,
     QT_API_PYSIDE6,
     # QT5
     QT_API_PYQT5,
     QT_API_PYSIDE2,
     # QT4
     QT_API_PYQTv1,
     QT_API_PYQT,
     QT_API_PYSIDE,
     # default
     QT_API_PYQT_DEFAULT,
 )
 
 _qt_apis = (
     # QT6
     QT_API_PYQT6,
     QT_API_PYSIDE6,
     # QT5
     QT_API_PYQT5,
     QT_API_PYSIDE2,
     # QT4
     QT_API_PYQTv1,
     QT_API_PYQT,
     QT_API_PYSIDE,
     # default
     QT_API_PYQT_DEFAULT,
 )
 
 
 def matplotlib_options(mpl):
     """Constraints placed on an imported matplotlib."""
     if mpl is None:
         return
     backend = mpl.rcParams.get('backend', None)
     if backend == 'Qt4Agg':
         mpqt = mpl.rcParams.get('backend.qt4', None)
         if mpqt is None:
             return None
         if mpqt.lower() == 'pyside':
             return [QT_API_PYSIDE]
         elif mpqt.lower() == 'pyqt4':
             return [QT_API_PYQT_DEFAULT]
         elif mpqt.lower() == 'pyqt4v2':
             return [QT_API_PYQT]
         raise ImportError("unhandled value for backend.qt4 from matplotlib: %r" %
                           mpqt)
     elif backend == 'Qt5Agg':
         mpqt = mpl.rcParams.get('backend.qt5', None)
         if mpqt is None:
             return None
         if mpqt.lower() == 'pyqt5':
             return [QT_API_PYQT5]
         raise ImportError("unhandled value for backend.qt5 from matplotlib: %r" %
                           mpqt)
 
 def get_options():
     print(f'`get_options` called with {os.environ.get("QT_API", None)=}')
     """Return a list of acceptable QT APIs, in decreasing order of preference."""
     #already imported Qt somewhere. Use that
     loaded = loaded_api()
     if loaded is not None:
+        print(f'`QtCore` already imported: {loaded=}')
         return [loaded]
 
     mpl = sys.modules.get('matplotlib', None)
     print(f'{mpl=}') # will be None of matplotlib has not yet been imported
 
     if mpl is not None and tuple(mpl.__version__.split(".")) < ("1", "0", "2"):
         # 1.0.1 only supports PyQt4 v1
         return [QT_API_PYQT_DEFAULT]
 
     qt_api = os.environ.get('QT_API', None)
     if qt_api is None:
         #no ETS variable. Ask mpl, then use default fallback path
         return matplotlib_options(mpl) or [
             QT_API_PYQT_DEFAULT,
             QT_API_PYQT6,
             QT_API_PYSIDE6,
             QT_API_PYQT5,
             QT_API_PYSIDE2,
             QT_API_PYQT,
             QT_API_PYSIDE,
         ]
     elif qt_api not in _qt_apis:
         raise RuntimeError("Invalid Qt API %r, valid values are: %r" %
                            (qt_api, ', '.join(_qt_apis)))
     else:
         print(f'{qt_api=}')
         return [qt_api]
 
 
 api_opts = get_options()
 print(f'Importing `IPython.terminal.pt_inputhooks.qt` with {api_opts=}')
 QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
 print(f'Loaded Qt with {QT_API=}')
 enum_helper = enum_factory(QT_API, QtCore)