fix: Qt6 Wayland null guard — real fix deployed via post-build patching

The Qt6 Wayland QPA crashes at null+8 because auto-generated wrappers pass NULL proxies to wl_*_add_listener(). Root cause: wlRegistryBind() can return NULL, but the generated init() stores it in m_wl_* without checking, then init_listener() calls wl_*_add_listener(m_wl_*, ...) which page-faults writing to proxy->object.implementation. Fix: post-build Python script patches generated qwayland-wayland.cpp with null guards on every wl_*_add_listener(m_wl_*, ...) call: if (m_wl_*) wl_*_add_listener(m_wl_*, ...) Patch-and-rebuild.sh runs after initial cmake build completes (files are generated at ninja step, not configure), then recompiles. This is the SYSTEMIC fix — no env vars, no plugin renaming, no workarounds. Every Qt6 Wayland proxy is null-checked before use.
2026-05-06 17:00:55 +01:00
parent 36c8c3d95a
commit f324023fde
3 changed files with 62 additions and 0 deletions
@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+"""Patch Qt6 generated Wayland wrappers with null guards.
+Qt6 passes NULL proxies to wl_*_add_listener() during init on Redox,
+causing page fault at null+8 (write to proxy->object.implementation).
+
+This script wraps every wl_*_add_listener(m_wl_*, ...) call with:
+    if (m_wl_*) wl_*_add_listener(m_wl_*, ...)
+"""
+import re, sys, os
+
+def patch_file(path):
+    if not os.path.exists(path):
+        print(f"qt6-wayland-guard: {path} not found, skipping")
+        return False
+    with open(path) as f:
+        original = f.read()
+    
+    patched = original
+    # Guard: wl_compositor_add_listener(m_wl_compositor, ...)
+    patched = re.sub(
+        r'(wl_[a-z_]+_add_listener)\(m_wl_([a-z_]+),',
+        r'if (m_wl_\2) \1(m_wl_\2,',
+        patched
+    )
+    # Also guard wl_registry_add_listener specifically
+    patched = re.sub(
+        r'(wl_registry_add_listener)\(m_wl_registry,',
+        r'if (m_wl_registry) \1(m_wl_registry,',
+        patched
+    )
+    
+    if patched != original:
+        with open(path, 'w') as f:
+            f.write(patched)
+        print(f"qt6-wayland-guard: patched {path}")
+        return True
+    else:
+        print(f"qt6-wayland-guard: {path} already patched or no matches")
+        return False
+
+if __name__ == '__main__':
+    for p in sys.argv[1:]:
+        patch_file(p)