Best-effort avoiding RecursionError in gc callback

hypothesis-python/src/hypothesis/internal/conjecture/junkdrawer.py

@@ -414,10 +414,20 @@ def _gc_callback(phase, _info):  # pragma: no cover  # called outside coverage b
 def gc_cumulative_time() -> float:
     global _gc_initialized
     if not _gc_initialized:
-        # Indirection via lambda to simplify monkeypatching of the callback fn
-        # - gc.callbacks can't be reassigned and hence is not suitable for
-        # monkeypatching directly. Don't remove this lambda without considering
-        # implications in tests/conftest.py.
-        gc.callbacks.insert(0, lambda *args: _gc_callback(*args))
+
+        def gc_callback(phase, info):
+            # There's not much that can fail here, but to avoid flakiness
+            # if collection is triggered near the recursion limit we temporarily
+            # bump to ensure there's headroom. Assuming the limit wasn't already
+            # exceeded by calling *this* method of course, but there's nothing we
+            # can do about that.
+            orig_recursionlimit = sys.getrecursionlimit()
+            sys.setrecursionlimit(orig_recursionlimit + 5)
+            try:
+                _gc_callback(phase, info)
+            finally:
+                sys.setrecursionlimit(orig_recursionlimit)
+
+        gc.callbacks.insert(0, gc_callback)
         _gc_initialized = True
     return _gc_cumulative_time