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Don't force matplotlib backend names to be lowercase (#14475)...
Don't force matplotlib backend names to be lowercase (#14475) This is something I missed as part of moving the backend resolution to Matplotlib. Since version 3.9.0 Matplotlib handles the case-sensitivity of backend names, making them all lowercase for internal use. But since matplotlib/matplotlib#28473 uppercase letters are allowed in backend names of the form `module://soMe_moDule.sOmE_NAme`. Hence we need to not force backend names to be lowercase in IPython when passing them to Matplotlib. It is just a one line change that happens to make the code simpler, plus a new test. The Matplotlib change will be released in 3.9.1 which is due shortly, possibly today. The new test checks the Matplotlib version to know whether uppercase backend module names are allowed or not.

File last commit:

r28138:b7632e01
r28831:6bde8f6c merge
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qt_loaders.py
410 lines | 11.2 KiB | text/x-python | PythonLexer
"""
This module contains factory functions that attempt
to return Qt submodules from the various python Qt bindings.
It also protects against double-importing Qt with different
bindings, which is unstable and likely to crash
This is used primarily by qt and qt_for_kernel, and shouldn't
be accessed directly from the outside
"""
import importlib.abc
import sys
import os
import types
from functools import partial, lru_cache
import operator
# ### Available APIs.
# Qt6
QT_API_PYQT6 = "pyqt6"
QT_API_PYSIDE6 = "pyside6"
# Qt5
QT_API_PYQT5 = 'pyqt5'
QT_API_PYSIDE2 = 'pyside2'
# Qt4
# NOTE: Here for legacy matplotlib compatibility, but not really supported on the IPython side.
QT_API_PYQT = "pyqt" # Force version 2
QT_API_PYQTv1 = "pyqtv1" # Force version 2
QT_API_PYSIDE = "pyside"
QT_API_PYQT_DEFAULT = "pyqtdefault" # use system default for version 1 vs. 2
api_to_module = {
# Qt6
QT_API_PYQT6: "PyQt6",
QT_API_PYSIDE6: "PySide6",
# Qt5
QT_API_PYQT5: "PyQt5",
QT_API_PYSIDE2: "PySide2",
# Qt4
QT_API_PYSIDE: "PySide",
QT_API_PYQT: "PyQt4",
QT_API_PYQTv1: "PyQt4",
# default
QT_API_PYQT_DEFAULT: "PyQt6",
}
class ImportDenier(importlib.abc.MetaPathFinder):
"""Import Hook that will guard against bad Qt imports
once IPython commits to a specific binding
"""
def __init__(self):
self.__forbidden = set()
def forbid(self, module_name):
sys.modules.pop(module_name, None)
self.__forbidden.add(module_name)
def find_spec(self, fullname, path, target=None):
if path:
return
if fullname in self.__forbidden:
raise ImportError(
"""
Importing %s disabled by IPython, which has
already imported an Incompatible QT Binding: %s
"""
% (fullname, loaded_api())
)
ID = ImportDenier()
sys.meta_path.insert(0, ID)
def commit_api(api):
"""Commit to a particular API, and trigger ImportErrors on subsequent
dangerous imports"""
modules = set(api_to_module.values())
modules.remove(api_to_module[api])
for mod in modules:
ID.forbid(mod)
def loaded_api():
"""Return which API is loaded, if any
If this returns anything besides None,
importing any other Qt binding is unsafe.
Returns
-------
None, 'pyside6', 'pyqt6', 'pyside2', 'pyside', 'pyqt', 'pyqt5', 'pyqtv1'
"""
if sys.modules.get("PyQt6.QtCore"):
return QT_API_PYQT6
elif sys.modules.get("PySide6.QtCore"):
return QT_API_PYSIDE6
elif sys.modules.get("PyQt5.QtCore"):
return QT_API_PYQT5
elif sys.modules.get("PySide2.QtCore"):
return QT_API_PYSIDE2
elif sys.modules.get("PyQt4.QtCore"):
if qtapi_version() == 2:
return QT_API_PYQT
else:
return QT_API_PYQTv1
elif sys.modules.get("PySide.QtCore"):
return QT_API_PYSIDE
return None
def has_binding(api):
"""Safely check for PyQt4/5, PySide or PySide2, without importing submodules
Parameters
----------
api : str [ 'pyqtv1' | 'pyqt' | 'pyqt5' | 'pyside' | 'pyside2' | 'pyqtdefault']
Which module to check for
Returns
-------
True if the relevant module appears to be importable
"""
module_name = api_to_module[api]
from importlib.util import find_spec
required = ['QtCore', 'QtGui', 'QtSvg']
if api in (QT_API_PYQT5, QT_API_PYSIDE2, QT_API_PYQT6, QT_API_PYSIDE6):
# QT5 requires QtWidgets too
required.append('QtWidgets')
for submod in required:
try:
spec = find_spec('%s.%s' % (module_name, submod))
except ImportError:
# Package (e.g. PyQt5) not found
return False
else:
if spec is None:
# Submodule (e.g. PyQt5.QtCore) not found
return False
if api == QT_API_PYSIDE:
# We can also safely check PySide version
import PySide
return PySide.__version_info__ >= (1, 0, 3)
return True
def qtapi_version():
"""Return which QString API has been set, if any
Returns
-------
The QString API version (1 or 2), or None if not set
"""
try:
import sip
except ImportError:
# as of PyQt5 5.11, sip is no longer available as a top-level
# module and needs to be imported from the PyQt5 namespace
try:
from PyQt5 import sip
except ImportError:
return
try:
return sip.getapi('QString')
except ValueError:
return
def can_import(api):
"""Safely query whether an API is importable, without importing it"""
if not has_binding(api):
return False
current = loaded_api()
if api == QT_API_PYQT_DEFAULT:
return current in [QT_API_PYQT6, None]
else:
return current in [api, None]
def import_pyqt4(version=2):
"""
Import PyQt4
Parameters
----------
version : 1, 2, or None
Which QString/QVariant API to use. Set to None to use the system
default
ImportErrors raised within this function are non-recoverable
"""
# The new-style string API (version=2) automatically
# converts QStrings to Unicode Python strings. Also, automatically unpacks
# QVariants to their underlying objects.
import sip
if version is not None:
sip.setapi('QString', version)
sip.setapi('QVariant', version)
from PyQt4 import QtGui, QtCore, QtSvg
if QtCore.PYQT_VERSION < 0x040700:
raise ImportError("IPython requires PyQt4 >= 4.7, found %s" %
QtCore.PYQT_VERSION_STR)
# Alias PyQt-specific functions for PySide compatibility.
QtCore.Signal = QtCore.pyqtSignal
QtCore.Slot = QtCore.pyqtSlot
# query for the API version (in case version == None)
version = sip.getapi('QString')
api = QT_API_PYQTv1 if version == 1 else QT_API_PYQT
return QtCore, QtGui, QtSvg, api
def import_pyqt5():
"""
Import PyQt5
ImportErrors raised within this function are non-recoverable
"""
from PyQt5 import QtCore, QtSvg, QtWidgets, QtGui
# Alias PyQt-specific functions for PySide compatibility.
QtCore.Signal = QtCore.pyqtSignal
QtCore.Slot = QtCore.pyqtSlot
# Join QtGui and QtWidgets for Qt4 compatibility.
QtGuiCompat = types.ModuleType('QtGuiCompat')
QtGuiCompat.__dict__.update(QtGui.__dict__)
QtGuiCompat.__dict__.update(QtWidgets.__dict__)
api = QT_API_PYQT5
return QtCore, QtGuiCompat, QtSvg, api
def import_pyqt6():
"""
Import PyQt6
ImportErrors raised within this function are non-recoverable
"""
from PyQt6 import QtCore, QtSvg, QtWidgets, QtGui
# Alias PyQt-specific functions for PySide compatibility.
QtCore.Signal = QtCore.pyqtSignal
QtCore.Slot = QtCore.pyqtSlot
# Join QtGui and QtWidgets for Qt4 compatibility.
QtGuiCompat = types.ModuleType("QtGuiCompat")
QtGuiCompat.__dict__.update(QtGui.__dict__)
QtGuiCompat.__dict__.update(QtWidgets.__dict__)
api = QT_API_PYQT6
return QtCore, QtGuiCompat, QtSvg, api
def import_pyside():
"""
Import PySide
ImportErrors raised within this function are non-recoverable
"""
from PySide import QtGui, QtCore, QtSvg
return QtCore, QtGui, QtSvg, QT_API_PYSIDE
def import_pyside2():
"""
Import PySide2
ImportErrors raised within this function are non-recoverable
"""
from PySide2 import QtGui, QtCore, QtSvg, QtWidgets, QtPrintSupport
# Join QtGui and QtWidgets for Qt4 compatibility.
QtGuiCompat = types.ModuleType('QtGuiCompat')
QtGuiCompat.__dict__.update(QtGui.__dict__)
QtGuiCompat.__dict__.update(QtWidgets.__dict__)
QtGuiCompat.__dict__.update(QtPrintSupport.__dict__)
return QtCore, QtGuiCompat, QtSvg, QT_API_PYSIDE2
def import_pyside6():
"""
Import PySide6
ImportErrors raised within this function are non-recoverable
"""
from PySide6 import QtGui, QtCore, QtSvg, QtWidgets, QtPrintSupport
# Join QtGui and QtWidgets for Qt4 compatibility.
QtGuiCompat = types.ModuleType("QtGuiCompat")
QtGuiCompat.__dict__.update(QtGui.__dict__)
QtGuiCompat.__dict__.update(QtWidgets.__dict__)
QtGuiCompat.__dict__.update(QtPrintSupport.__dict__)
return QtCore, QtGuiCompat, QtSvg, QT_API_PYSIDE6
def load_qt(api_options):
"""
Attempt to import Qt, given a preference list
of permissible bindings
It is safe to call this function multiple times.
Parameters
----------
api_options : List of strings
The order of APIs to try. Valid items are 'pyside', 'pyside2',
'pyqt', 'pyqt5', 'pyqtv1' and 'pyqtdefault'
Returns
-------
A tuple of QtCore, QtGui, QtSvg, QT_API
The first three are the Qt modules. The last is the
string indicating which module was loaded.
Raises
------
ImportError, if it isn't possible to import any requested
bindings (either because they aren't installed, or because
an incompatible library has already been installed)
"""
loaders = {
# Qt6
QT_API_PYQT6: import_pyqt6,
QT_API_PYSIDE6: import_pyside6,
# Qt5
QT_API_PYQT5: import_pyqt5,
QT_API_PYSIDE2: import_pyside2,
# Qt4
QT_API_PYSIDE: import_pyside,
QT_API_PYQT: import_pyqt4,
QT_API_PYQTv1: partial(import_pyqt4, version=1),
# default
QT_API_PYQT_DEFAULT: import_pyqt6,
}
for api in api_options:
if api not in loaders:
raise RuntimeError(
"Invalid Qt API %r, valid values are: %s" %
(api, ", ".join(["%r" % k for k in loaders.keys()])))
if not can_import(api):
continue
#cannot safely recover from an ImportError during this
result = loaders[api]()
api = result[-1] # changed if api = QT_API_PYQT_DEFAULT
commit_api(api)
return result
else:
# Clear the environment variable since it doesn't work.
if "QT_API" in os.environ:
del os.environ["QT_API"]
raise ImportError(
"""
Could not load requested Qt binding. Please ensure that
PyQt4 >= 4.7, PyQt5, PyQt6, PySide >= 1.0.3, PySide2, or
PySide6 is available, and only one is imported per session.
Currently-imported Qt library: %r
PyQt5 available (requires QtCore, QtGui, QtSvg, QtWidgets): %s
PyQt6 available (requires QtCore, QtGui, QtSvg, QtWidgets): %s
PySide2 installed: %s
PySide6 installed: %s
Tried to load: %r
"""
% (
loaded_api(),
has_binding(QT_API_PYQT5),
has_binding(QT_API_PYQT6),
has_binding(QT_API_PYSIDE2),
has_binding(QT_API_PYSIDE6),
api_options,
)
)
def enum_factory(QT_API, QtCore):
"""Construct an enum helper to account for PyQt5 <-> PyQt6 changes."""
@lru_cache(None)
def _enum(name):
# foo.bar.Enum.Entry (PyQt6) <=> foo.bar.Entry (non-PyQt6).
return operator.attrgetter(
name if QT_API == QT_API_PYQT6 else name.rpartition(".")[0]
)(sys.modules[QtCore.__package__])
return _enum