Merge main; sync bindings 22f8383 (lvgl-bindings#36 as merged)

The generated files, lv_conf.h and fs_driver.py are byte-identical to
lvgl-bindings at 22f8383, and the lvgl submodule pin is unchanged; only
LVGL_BINDINGS_COMMIT moves from the pre-merge be7654f.

Author: bdbarnett

LVGL_BINDINGS_COMMIT

@@ -1 +1 @@
-be7654f89cd7fb3e573c2721c26a68c1a778b324
+22f8383eedc785a6c87c57c7ed46c95c454cebe3

tests/test_callback_references.py

@@ -0,0 +1,119 @@
+# SPDX-License-Identifier: MIT
+"""References a callback trampoline holds while LVGL calls into Python.
+
+- A callback that replaces its own registration while it runs
+  (``timer.set_cb(other)`` from inside the timer callback) stays alive until
+  it returns. Before, the only reference was the callback dict's, so the
+  replacement freed the callback mid-call.
+- Arguments passed to a callback are released after the call. Before, every
+  call leaked one reference to each argument, so a widget handed to a
+  ``tree_walk`` callback was never freed.
+
+The checks run in one subprocess under MALLOC_PERTURB_ so a use-after-free
+shows up as a crash rather than luck.
+"""
+
+import json
+import os
+import subprocess
+import sys
+import unittest
+
+
+_SCRIPT = r"""
+import gc
+import json
+import sys
+import weakref
+
+import lvgl as lv
+
+lv.init()
+disp = lv.display_create(64, 64)
+disp.set_color_format(lv.COLOR_FORMAT.RGB565)
+buf = lv.draw_buf_create(64, 64, lv.COLOR_FORMAT.RGB565, 0)
+disp.set_draw_buffers(buf, None)
+disp.set_render_mode(lv.DISPLAY_RENDER_MODE.PARTIAL)
+scr = lv.screen_active()
+out = {}
+
+
+def pump(ms):
+    for _ in range(ms // 5):
+        lv.tick_inc(5)
+        lv.timer_handler()
+
+
+# A callback that replaces itself stays alive until it returns.
+timer = lv.timer_create_basic()
+timer.set_period(10)
+
+
+class Replaces:
+    def __call__(self, t):
+        ref = weakref.ref(self)
+        del self
+        timer.set_cb(lambda t: None)
+        gc.collect()
+        out["alive_after_replacing_itself"] = ref() is not None
+
+
+timer.set_cb(Replaces())
+pump(50)
+timer.delete()
+
+
+# Callback arguments are released after the call.
+child = lv.button(scr)
+
+def walk(obj, user_data):
+    return lv.obj.TREE_WALK.NEXT
+
+before = sys.getrefcount(child)
+for _ in range(10):
+    scr.tree_walk(walk, None)
+out["tree_walk_arg_refcount_delta"] = sys.getrefcount(child) - before
+
+child.delete()
+lv.deinit()
+print("RESULT " + json.dumps(out))
+"""
+
+
+def _run():
+    env = dict(os.environ)
+    env["MALLOC_PERTURB_"] = "165"
+    proc = subprocess.run(
+        [sys.executable, "-c", _SCRIPT],
+        capture_output=True,
+        text=True,
+        timeout=120,
+        env=env,
+    )
+    for line in proc.stdout.splitlines():
+        if line.startswith("RESULT "):
+            return proc, json.loads(line[len("RESULT "):])
+    return proc, None
+
+
+class CallbackReferenceTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.proc, cls.out = _run()
+
+    def setUp(self):
+        if self.out is None:
+            self.fail(
+                "script did not finish (exit %s)\nstdout:\n%s\nstderr:\n%s"
+                % (self.proc.returncode, self.proc.stdout, self.proc.stderr)
+            )
+
+    def test_callback_outlives_replacing_itself(self):
+        self.assertIs(self.out.get("alive_after_replacing_itself"), True)
+
+    def test_callback_arguments_are_released(self):
+        self.assertEqual(self.out["tree_walk_arg_refcount_delta"], 0)
+
+
+if __name__ == "__main__":
+    unittest.main()