Centralize array storage options and implement field-level merging in Orbax v1.

checkpoint/CHANGELOG.md

@@ -22,6 +22,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Enforce the array shape and type check during Array restoration when
   `ArrayRestoreArgs.strict` is set but shape/dtype is not provided.
 - On platforms where `uvloop` is not supported, fallback to `nest_asyncio`.
+- #v1 Centralize `StorageOptions` into `ArrayOptions` and implement field-level
+merging.
 
 ## [0.11.33] - 2026-02-17
 

checkpoint/orbax/checkpoint/experimental/v1/_src/context/options.py

@@ -184,27 +184,6 @@ class PyTreeOptions:
 
   # TODO: Include an example of registering a custom LeafHandler.
 
-  Example:
-    To save certain leaves in float16, while others in float32, we can use
-    `create_array_storage_options_fn` like so::
-
-      import jax
-      import jax.numpy as jnp
-      from orbax.checkpoint.v1 import options as ocp_options
-
-      def create_opts_fn(keypath, value):
-        if 'small' in jax.tree_util.keystr(keypath):
-          return ocp_options.ArrayOptions.Saving.StorageOptions(
-              dtype=jnp.float16
-          )
-        return ocp_options.ArrayOptions.Saving.StorageOptions(dtype=jnp.float32)
-
-      pytree_options = ocp_options.PyTreeOptions(
-          saving=ocp_options.PyTreeOptions.Saving(
-              create_array_storage_options_fn=create_opts_fn
-          )
-      )
-
   Attributes:
     saving: Options for saving PyTrees.
     loading: Options for loading PyTrees.
@@ -216,25 +195,9 @@ def create_opts_fn(keypath, value):
   class Saving:
     """Options for saving PyTrees.
 
-    create_array_storage_options_fn:
-      A function that is called in order to create
-      :py:class:`.ArrayOptions.Saving.StorageOptions` for each leaf in a PyTree,
-      when it is
-      being saved. It is called similar to:
-      `jax.tree.map_with_path(create_array_storage_options_fn, pytree_to_save)`.
-      If provided, it overrides any default settings in
-      :py:class:`.ArrayOptions.Saving.StorageOptions`.
     pytree_metadata_options: Options for managing PyTree metadata.
     """
 
-    class CreateArrayStorageOptionsFn(Protocol):
-
-      def __call__(
-          self, key: tree_types.PyTreeKeyPath, value: Any
-      ) -> ArrayOptions.Saving.StorageOptions:
-        ...
-
-    create_array_storage_options_fn: CreateArrayStorageOptionsFn | None = None
     pytree_metadata_options: tree_metadata.PyTreeMetadataOptions = (
         dataclasses.field(default_factory=tree_metadata.PyTreeMetadataOptions)
     )
@@ -265,7 +228,8 @@ class ArrayOptions:
   names during initialization.
 
   Example:
-    Configure array options with specific saving formats and loading behaviors::
+    To configure array options with specific saving formats and loading
+    behaviors we can do so like this::
 
       from orbax.checkpoint.v1.options import ArrayOptions
 
@@ -280,6 +244,30 @@ class ArrayOptions:
           )
       )
 
+    To save certain leaves in float16, while others in float32, we can use
+    `scoped_storage_options_creator` like so::
+
+      import jax
+      import jax.numpy as jnp
+      from orbax.checkpoint.v1 import options as ocp_options
+
+      def create_opts_fn(keypath, value):
+        if 'small' in jax.tree_util.keystr(keypath):
+          return ocp_options.ArrayOptions.Saving.StorageOptions(
+              dtype=jnp.float16
+          )
+        return None  # Fall back to global `storage_options`
+
+      array_options = ocp_options.ArrayOptions(
+          saving=ocp_options.ArrayOptions.Saving(
+              storage_options=ocp_options.ArrayOptions.Saving.StorageOptions(
+                  dtype=jnp.float32
+              ),
+              scoped_storage_options_creator=create_opts_fn
+          )
+
+      )
+
   Attributes:
     saving: Options for saving arrays.
     loading: Options for loading arrays.
@@ -322,8 +310,24 @@ class Saving:
         True.
       array_metadata_store: Store to manage per host ArrayMetadata. To disable
         ArrayMetadata persistence, set it to None.
+      storage_options: Global default for array storage options.
+      scoped_storage_options_creator: A function that, when dealing with
+        PyTrees, is applied to every leaf. If it returns an
+        :py:class:`ArrayOptions.Saving.StorageOptions`, its fields take
+        precedence when merging if they are set to non-None or non-default
+        values with respect to `storage_options`. If it returns `None`,
+        `storage_options` is used as a default for all fields. It is called
+        similar to: `jax.tree.map_with_path(scoped_storage_options_creator,
+        pytree_to_save)`.
     """
 
+    class ScopedStorageOptionsCreator(Protocol):
+
+      def __call__(
+          self, key: tree_types.PyTreeKeyPath, value: Any
+      ) -> ArrayOptions.Saving.StorageOptions:
+        ...
+
     @dataclasses.dataclass(frozen=True, kw_only=True)
     class StorageOptions:
       """Options used to customize array storage behavior for individual leaves.
@@ -367,6 +371,7 @@ class StorageOptions:
     array_metadata_store: array_metadata_store_lib.Store | None = (
         array_metadata_store_lib.Store()
     )
+    scoped_storage_options_creator: ScopedStorageOptionsCreator | None = None
 
   @dataclasses.dataclass(frozen=True, kw_only=True)
   class Loading:

checkpoint/orbax/checkpoint/experimental/v1/_src/handlers/pytree_handler.py

@@ -29,13 +29,15 @@
 from orbax.checkpoint._src.futures import synchronization
 from orbax.checkpoint._src.handlers import base_pytree_checkpoint_handler
 from orbax.checkpoint._src.metadata import array_metadata_store as array_metadata_store_lib
+from orbax.checkpoint._src.serialization import type_handlers as type_handlers_v0
 from orbax.checkpoint._src.serialization import types as v0_serialization_types
 from orbax.checkpoint.experimental.v1._src.context import context as context_lib
 from orbax.checkpoint.experimental.v1._src.context import options as options_lib
 from orbax.checkpoint.experimental.v1._src.handlers import types as handler_types
 from orbax.checkpoint.experimental.v1._src.metadata import types as metadata_types
 from orbax.checkpoint.experimental.v1._src.path import types as path_types
 from orbax.checkpoint.experimental.v1._src.serialization import compatibility
+from orbax.checkpoint.experimental.v1._src.serialization import options_resolution
 from orbax.checkpoint.experimental.v1._src.serialization import protocol_utils
 from orbax.checkpoint.experimental.v1._src.serialization import registry
 from orbax.checkpoint.experimental.v1._src.serialization import scalar_leaf_handler
@@ -69,32 +71,19 @@ def _get_remaining_timeout(
 
 def _get_v0_save_args(
     checkpointable: PyTree,
-    array_storage_options: options_lib.ArrayOptions.Saving.StorageOptions,
-    create_array_storage_options_fn: (
-        options_lib.PyTreeOptions.Saving.CreateArrayStorageOptionsFn | None
-    ),
+    array_saving_options: options_lib.ArrayOptions.Saving,
 ) -> PyTree:
   """Returns save args that are compatible with the V0 API."""
-
   def _leaf_get_v0_save_args(k, v):
-    if create_array_storage_options_fn:
-      individual_array_storage_options = create_array_storage_options_fn(k, v)
-      save_dtype = (
-          np.dtype(individual_array_storage_options.dtype)
-          if individual_array_storage_options.dtype
-          else None
-      )
-      return v0_serialization_types.SaveArgs(
-          dtype=save_dtype,
-          chunk_byte_size=individual_array_storage_options.chunk_byte_size,
-          shard_axes=individual_array_storage_options.shard_axes,
-      )
-    return v0_serialization_types.SaveArgs(
-        dtype=np.dtype(array_storage_options.dtype)
-        if array_storage_options.dtype
+    resolved_options = options_resolution.resolve_storage_options(
+        k, v, array_saving_options
+    )
+    return type_handlers_v0.SaveArgs(
+        dtype=np.dtype(resolved_options.dtype)
+        if resolved_options.dtype is not None
         else None,
-        chunk_byte_size=array_storage_options.chunk_byte_size,
-        shard_axes=array_storage_options.shard_axes,
+        chunk_byte_size=resolved_options.chunk_byte_size,
+        shard_axes=resolved_options.shard_axes,
     )
 
   return jax.tree.map_with_path(_leaf_get_v0_save_args, checkpointable)
@@ -135,8 +124,7 @@ def create_v0_save_args(
       item=checkpointable,
       save_args=_get_v0_save_args(
           checkpointable,
-          context.array_options.saving.storage_options,
-          context.pytree_options.saving.create_array_storage_options_fn,
+          context.array_options.saving,
       ),
       ocdbt_target_data_file_size=context.array_options.saving.ocdbt_target_data_file_size,
   )

checkpoint/orbax/checkpoint/experimental/v1/_src/serialization/array_leaf_handler.py

@@ -32,6 +32,8 @@
 from orbax.checkpoint._src.metadata import value as value_metadata
 from orbax.checkpoint._src.serialization import type_handlers as type_handlers_v0
 from orbax.checkpoint.experimental.v1._src.context import context as context_lib
+import orbax.checkpoint.experimental.v1._src.context.options as options_lib
+from orbax.checkpoint.experimental.v1._src.serialization import options_resolution
 from orbax.checkpoint.experimental.v1._src.serialization import protocol_utils
 from orbax.checkpoint.experimental.v1._src.serialization import registration
 from orbax.checkpoint.experimental.v1._src.serialization import types
@@ -109,18 +111,18 @@ def _create_v0_saving_paraminfo(
 
 def _create_v0_savearg(
     param: ArraySerializationParam,
-    context: context_lib.Context,
+    array_saving_options: options_lib.ArrayOptions.Saving,
 ) -> type_handlers_v0.SaveArgs:
-  """Creates a V0 `SaveArgs` from V1 params and context for saving."""
-  fn = context.pytree_options.saving.create_array_storage_options_fn
-  if fn:
-    storage_options = fn(param.keypath, param.value)
-  else:
-    storage_options = context.array_options.saving.storage_options
+  """Creates a V0 `SaveArgs` from V1 params and array options for saving."""
+  resolved_options = options_resolution.resolve_storage_options(
+      param.keypath, param.value, array_saving_options
+  )
   return type_handlers_v0.SaveArgs(
-      dtype=jnp.dtype(storage_options.dtype) if storage_options.dtype else None,
-      chunk_byte_size=storage_options.chunk_byte_size,
-      shard_axes=storage_options.shard_axes,
+      dtype=jnp.dtype(resolved_options.dtype)
+      if resolved_options.dtype is not None
+      else None,
+      chunk_byte_size=resolved_options.chunk_byte_size,
+      shard_axes=resolved_options.shard_axes,
   )
 
 
@@ -223,7 +225,10 @@ async def serialize(
         _create_v0_saving_paraminfo(p, self._context, serialization_context)
         for p in params
     ]
-    saveargs = [_create_v0_savearg(p, self._context) for p in params]
+    saveargs = [
+        _create_v0_savearg(p, self._context.array_options.saving)
+        for p in params
+    ]
 
     commit_futures = await self._handler_impl.serialize(
         values, paraminfos, saveargs

checkpoint/orbax/checkpoint/experimental/v1/_src/serialization/numpy_leaf_handler.py

@@ -30,6 +30,8 @@
 from orbax.checkpoint._src.metadata import value as value_metadata
 from orbax.checkpoint._src.serialization import type_handlers as type_handlers_v0
 from orbax.checkpoint.experimental.v1._src.context import context as context_lib
+import orbax.checkpoint.experimental.v1._src.context.options as options_lib
+from orbax.checkpoint.experimental.v1._src.serialization import options_resolution
 from orbax.checkpoint.experimental.v1._src.serialization import registration
 from orbax.checkpoint.experimental.v1._src.serialization import types
 
@@ -96,18 +98,18 @@ def _create_v0_saving_paraminfo(
 
 def _create_v0_savearg(
     param: NumpySerializationParam,
-    context: context_lib.Context,
+    array_saving_options: options_lib.ArrayOptions.Saving,
 ) -> type_handlers_v0.SaveArgs:
-  """Creates a V0 `SaveArgs` from V1 params and context for saving."""
-  fn = context.pytree_options.saving.create_array_storage_options_fn
-  if fn:
-    storage_options = fn(param.keypath, param.value)
-  else:
-    storage_options = context.array_options.saving.storage_options
+  """Creates a V0 `SaveArgs` from V1 params and array saving options."""
+  resolved_options = options_resolution.resolve_storage_options(
+      param.keypath, param.value, array_saving_options
+  )
   return type_handlers_v0.SaveArgs(
-      dtype=np.dtype(storage_options.dtype) if storage_options.dtype else None,
-      chunk_byte_size=storage_options.chunk_byte_size,
-      shard_axes=storage_options.shard_axes,
+      dtype=np.dtype(resolved_options.dtype)
+      if resolved_options.dtype is not None
+      else None,
+      chunk_byte_size=resolved_options.chunk_byte_size,
+      shard_axes=resolved_options.shard_axes,
   )
 
 
@@ -188,7 +190,10 @@ async def serialize(
         _create_v0_saving_paraminfo(p, self._context, serialization_context)
         for p in params
     ]
-    saveargs = [_create_v0_savearg(p, self._context) for p in params]
+    saveargs = [
+        _create_v0_savearg(p, self._context.array_options.saving)
+        for p in params
+    ]
 
     commit_futures = await self._handler_impl.serialize(
         values, paraminfos, saveargs

checkpoint/orbax/checkpoint/experimental/v1/_src/serialization/options_resolution.py

@@ -0,0 +1,77 @@
+# Copyright 2026 The Orbax Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Utility functions for serialization."""
+
+from orbax.checkpoint.experimental.v1._src.context import options as options_lib
+from orbax.checkpoint.experimental.v1._src.tree import types as tree_types
+
+
+def resolve_storage_options(
+    keypath: tree_types.PyTreeKeyPath,
+    value: tree_types.LeafType,
+    array_saving_options: options_lib.ArrayOptions.Saving,
+) -> options_lib.ArrayOptions.Saving.StorageOptions:
+  """Resolves storage options using a global default and a per-leaf creator.
+
+  When dealing with PyTrees, `scoped_storage_options_creator` is applied to
+  every leaf. Its fields take precedence when merging if they are set to
+  non-None or non-default values with respect to the global `storage_options`.
+  If the creator returns `None`, the global `storage_options` is used for all
+  fields.
+
+  Args:
+    keypath: The PyTree keypath of the array being saved.
+    value: The PyTree leaf value (array) being saved.
+    array_saving_options: The Orbax array saving options to use for resolution.
+
+  Returns:
+    The resolved StorageOptions containing storage options.
+  """
+  global_opts = array_saving_options.storage_options
+  if global_opts is None:
+    global_opts = options_lib.ArrayOptions.Saving.StorageOptions()
+
+  fn = array_saving_options.scoped_storage_options_creator
+  individual_opts = None
+  if fn is not None:
+    individual_opts = fn(keypath, value)
+
+  if individual_opts is not None:
+    resolved_dtype = (
+        individual_opts.dtype
+        if individual_opts.dtype is not None
+        else global_opts.dtype
+    )
+    resolved_chunk_byte_size = (
+        individual_opts.chunk_byte_size
+        if individual_opts.chunk_byte_size is not None
+        else global_opts.chunk_byte_size
+    )
+    resolved_shard_axes = (
+        individual_opts.shard_axes
+        if individual_opts.shard_axes
+        else global_opts.shard_axes
+    )
+  else:
+    resolved_dtype = global_opts.dtype
+    resolved_chunk_byte_size = global_opts.chunk_byte_size
+    resolved_shard_axes = global_opts.shard_axes
+
+  return options_lib.ArrayOptions.Saving.StorageOptions(
+      dtype=resolved_dtype,
+      chunk_byte_size=resolved_chunk_byte_size,
+      shard_axes=resolved_shard_axes,
+  )
+