ROOT CAUSE: Qt6's auto-generated Wayland wrappers pass NULL proxies
to wl_*_add_listener() during initialization. The generated code stores
wlRegistryBind() return value in m_wl_* member without null check,
then init_listener() calls wl_*_add_listener(m_wl_*, ...) which
page-faults at null+8 (write to proxy->object.implementation).
FIX (kded6): wrapper script renames libqwayland.so to .disabled
before launching kded6.real. QT_QPA_PLATFORM=offscreen alone is not
sufficient — Qt6 still loads wayland plugin despite env var.
FIX (libwayland): null guards in redox.patch for wl_proxy_add_listener,
wl_proxy_get_version, wl_proxy_get_display. Blocked from compilation
by pre-existing relibc conflicts (open_memstream, signalfd_siginfo).
FIX (Qt6 wrappers): regex-based null guard insertion proven in concept.
Blocked by TOML recipe format not supporting backslash escape sequences.
Implementation plan: inject null guards via a separate build step script
rather than inline in recipe.toml.
- WAYLAND-IMPLEMENTATION-PLAN.md v2.0: document architecture decision
that Wayland is the only supported display path. Remove all
framebuffer fallback workarounds (offscreen QPA, redox QPA shim).
- qwaylanddisplay.cpp: add fprintf instrumentation for crash diagnosis;
skip xkb_context_new on Redox to eliminate potential xkb crash vector.
- greeter-ui/main.cpp: remove QT_QPA_PLATFORM=redox workaround.
The greeter must use Wayland. Accept the crash until Qt6 is fixed.
- Ruled out: relibc calloc (zeroes correctly), libwayland proxy_create
(correct), compositor protocol (compliant). Root cause is in Qt6
generated Wayland wrappers passing NULL to wl_proxy_add_listener.
vasilito