PySide6: Use the Python version the plugin is running under

Task-number: PYSIDE-1455
Change-Id: Iba9429d2c42f471661b250829aaf124a4b8b72b2
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
Reviewed-by: Christian Tismer <tismer@stackless.com>
(cherry picked from commit 1da27a40a71e61f4ac4bc83819ade1461efb17fc)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 14 insertions, 2 deletions

diff --git a/sources/pyside-tools/pyside_tool.py b/sources/pyside-tools/pyside_tool.py
index da29025c8..52716e308 100644
--- a/sources/pyside-tools/pyside_tool.py
+++ b/sources/pyside-tools/pyside_tool.py
@@ -101,9 +101,13 @@ def designer():
     # python executable is involved when loading this plugin, pre-load python.so
     # This should also help to work around a numpy issue, see
     # https://stackoverflow.com/questions/49784583/numpy-import-fails-on-multiarray-extension-library-when-called-from-embedded-pyt
+    major_version = sys.version_info[0]
+    minor_version = sys.version_info[1]
+    os.environ['PY_MAJOR_VERSION'] = str(major_version)
+    os.environ['PY_MINOR_VERSION'] = str(minor_version)
     if sys.platform == 'linux':
         # Determine library name (examples/utils/pyside_config.py)
-        version = f'{sys.version_info[0]}.{sys.version_info[1]}'
+        version = f'{major_version}.{minor_version}'
         library_name = f'libpython{version}{sys.abiflags}.so'
         os.environ['LD_PRELOAD'] = library_name
 
diff --git a/sources/pyside6/plugins/designer/designercustomwidgets.cpp b/sources/pyside6/plugins/designer/designercustomwidgets.cpp
index 92455cc24..65074c546 100644
--- a/sources/pyside6/plugins/designer/designercustomwidgets.cpp
+++ b/sources/pyside6/plugins/designer/designercustomwidgets.cpp
@@ -163,9 +163,17 @@ static void initVirtualEnvironment()
     // As of Python 3.8/Windows, Python is no longer able to run stand-alone in
     // a virtualenv due to missing libraries. Add the path to the modules
     // instead.
+    bool ok;
+    int majorVersion = qEnvironmentVariableIntValue("PY_MAJOR_VERSION", &ok);
+    int minorVersion = qEnvironmentVariableIntValue("PY_MINOR_VERSION", &ok);
+    if (!ok) {
+        majorVersion = PY_MAJOR_VERSION;
+        minorVersion = PY_MINOR_VERSION;
+    }
+
     if (!qEnvironmentVariableIsSet(virtualEnvVar)
         || QOperatingSystemVersion::currentType() != QOperatingSystemVersion::Windows
-        || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 8)) {
+        || (majorVersion == 3 && minorVersion < 8)) {
         return;
     }