Qt bootstrap assumes every native Qt library has a corresponding PySide wrapper #3395

Title: Qt bootstrap assumes every native Qt library has a corresponding PySide wrapper

Description:

I found an issue in the python-for-android Qt bootstrap when it is used by PySide6.

Environment:

• PySide6: 6.12
• Python: 3.14
• Android ABI: arm64-v8a
• Android emulator: Android 16
• Android NDK: r28c
• Qt Quick / Qt Quick Controls

The PySide Android deployment correctly needs to pass native Qt dependencies such as:

Core
Gui
Network
Qml
OpenGL
QmlModels
QmlWorkerScript
QmlMeta
Quick
QuickTemplates2
QuickControls2

The problem is in:

pythonforandroid/bootstraps/qt/build/templates/libs.tmpl.xml

The current template iterates over qt_libs and generates both:

Qt6<Module>_<arch>

for native Qt libraries, and:

Qt<Module>.abi3.so

for PySide wrapper libraries.

These two sets are not equivalent.

Some native Qt dependencies do not have a corresponding PySide wrapper library.

For example:

QmlModels
QmlWorkerScript
QmlMeta
QuickTemplates2

are valid native Qt dependencies, but the corresponding wrapper libraries do not exist in the PySide wheel:

QtQmlModels.abi3.so
QtQmlWorkerScript.abi3.so
QtQmlMeta.abi3.so
QtQuickTemplates2.abi3.so

As a result, the generated load_local_libs array can contain non-existent libraries.

The runtime then fails with an error like:

dlopen failed: library ".../QtQmlModels.abi3.so" not found
java.lang.UnsatisfiedLinkError
Loading Qt native libraries failed

Root cause:

qt_libs is currently used for two different purposes:

1. native Qt libraries;
2. PySide wrapper libraries.

This assumption is not always valid.

Suggested solution:

Introduce a separate list/argument for PySide wrapper modules, for example:

--pyside-libs

Then:

qt_libs

should be used only for native Qt libraries, while:

pyside_libs

should be used only to generate:

Qt<Module>.abi3.so

entries in load_local_libs.

For backward compatibility, if --pyside-libs is not provided, it could fall back to qt_libs.

Conceptually:

pyside_libs = (
    args.pyside_libs.split(",")
    if args.pyside_libs
    else qt_libs
)

and in libs.tmpl.xml:

{%- for pyside_lib in pyside_libs %}
<item>{{ arch }};Qt{{ pyside_lib }}.abi3.so</item>
{% if pyside_lib == "Qml" -%}
<item>{{ arch }};libpyside6qml.abi3.so</item>
{% endif %}
{%- endfor -%}

I implemented this locally and tested it successfully.

After separating native Qt libraries from PySide wrapper libraries:

• the application starts correctly;
• Qt Quick Controls work;
• no non-existent Qt*.abi3.so libraries are loaded;
• no UnsatisfiedLinkError occurs;
• QML to Python interaction works correctly.

The relevant files are:

pythonforandroid/bootstraps/common/build/build.py
pythonforandroid/bootstraps/qt/build/templates/libs.tmpl.xml

This issue is related to PySide Android deployment, because PySide may need to pass native Qt-only dependencies which do not have Python wrapper libraries.

I have a working local implementation and can provide the diff if useful.

python-for-android-fix.patch

python-for-android-fix.patch