Update libraries to use JAX's limited (and ill-advised) trace-state-querying APIs rather than depending on JAX's deeper internals, which are about to change.

flax/core/__init__.py

@@ -48,9 +48,8 @@
 from .tracers import (
     check_trace_level as check_trace_level,
     current_trace as current_trace,
-    trace_level as trace_level,
 )
 
 from flax.typing import (
     Array as Array,
-)
+)

flax/core/scope.py

@@ -454,7 +454,7 @@ def __init__(
     self.flags = freeze({} if flags is None else flags)
 
     self._root = parent.root if parent else None
-    self.trace_level = tracers.trace_level(tracers.current_trace())
+    self.trace_level = tracers.current_trace()
 
     self.rng_counters = {key: 0 for key in self.rngs}
     self.reservations = collections.defaultdict(set)

flax/core/tracers.py

@@ -20,18 +20,17 @@
 
 
 def current_trace():
-  """Returns the innermost Jax tracer."""
-  return jax.core.find_top_trace(())
-
-
-def trace_level(main):
-  """Returns the level of the trace of -infinity if it is None."""
-  if main:
-    return main.level
-  return float('-inf')
+  """Returns the current JAX state tracer."""
+  if jax.__version_info__ <= (0, 4, 33):
+    top = jax.core.find_top_trace(())
+    if top:
+      return top.level
+    else:
+      return float('-inf')
 
+  return jax.core.get_opaque_trace_state(convention="flax")
 
 def check_trace_level(base_level):
-  level = trace_level(current_trace())
+  level = current_trace()
   if level != base_level:
     raise errors.JaxTransformError()

flax/nnx/tracers.py

@@ -15,14 +15,16 @@
 # Taken from flax/core/tracer.py 🏴‍☠️
 
 
-from jax.core import MainTrace, thread_local_state
+from jax.core import get_opaque_trace_state, OpaqueTraceState
 
 from flax.nnx import reprlib
 
 
-def current_jax_trace() -> MainTrace:
-  """Returns the innermost Jax tracer."""
-  return thread_local_state.trace_state.trace_stack.dynamic
+def current_jax_trace() -> OpaqueTraceState:
+  """Returns the Jax tracing state."""
+  if jax.__version_info__ <= (0, 4, 33):
+    return thread_local_state.trace_state.trace_stack.dynamic
+  return get_opaque_trace_state(convention="nnx")
 
 
 class TraceState(reprlib.Representable):
@@ -36,7 +38,10 @@ def jax_trace(self):
     return self._jax_trace
 
   def is_valid(self) -> bool:
-    return self._jax_trace is current_jax_trace()
+    if jax.__version_info__ <= (0, 4, 33):
+      return self._jax_trace is current_jax_trace()
+
+    return self._jax_trace == current_jax_trace()
 
   def __nnx_repr__(self):
     yield reprlib.Object(f'{type(self).__name__}')
@@ -52,4 +57,7 @@ def __treescope_repr__(self, path, subtree_renderer):
     )
 
   def __eq__(self, other):
-    return isinstance(other, TraceState) and self._jax_trace is other._jax_trace
+    if jax.__version_info__ <= (0, 4, 33):
+      return isinstance(other, TraceState) and self._jax_trace is other._jax_trace
+
+    return isinstance(other, TraceState) and self._jax_trace == other._jax_trace