perf(client): optimize file structure copying in multipart requests

Author: stainless-app[bot]

src/anthropic/_files.py

@@ -3,8 +3,8 @@
 import io
 import os
 import pathlib
-from typing import overload
-from typing_extensions import TypeGuard
+from typing import Sequence, cast, overload
+from typing_extensions import TypeVar, TypeGuard
 
 import anyio
 
@@ -17,7 +17,9 @@
     HttpxFileContent,
     HttpxRequestFiles,
 )
-from ._utils import is_tuple_t, is_mapping_t, is_sequence_t
+from ._utils import is_list, is_mapping, is_tuple_t, is_mapping_t, is_sequence_t
+
+_T = TypeVar("_T")
 
 
 def is_base64_file_input(obj: object) -> TypeGuard[Base64FileInput]:
@@ -121,3 +123,51 @@ async def async_read_file_content(file: FileContent) -> HttpxFileContent:
         return await anyio.Path(file).read_bytes()
 
     return file
+
+
+def deepcopy_with_paths(item: _T, paths: Sequence[Sequence[str]]) -> _T:
+    """Copy only the containers along the given paths.
+
+    Used to guard against mutation by extract_files without copying the entire structure.
+    Only dicts and lists that lie on a path are copied; everything else
+    is returned by reference.
+
+    For example, given paths=[["foo", "files", "file"]] and the structure:
+        {
+            "foo": {
+                "bar": {"baz": {}},
+                "files": {"file": <content>}
+            }
+        }
+    The root dict, "foo", and "files" are copied (they lie on the path).
+    "bar" and "baz" are returned by reference (off the path).
+    """
+    return _deepcopy_with_paths(item, paths, 0)
+
+
+def _deepcopy_with_paths(item: _T, paths: Sequence[Sequence[str]], index: int) -> _T:
+    if not paths:
+        return item
+    if is_mapping(item):
+        key_to_paths: dict[str, list[Sequence[str]]] = {}
+        for path in paths:
+            if index < len(path):
+                key_to_paths.setdefault(path[index], []).append(path)
+
+        # if no path continues through this mapping, it won't be mutated and copying it is redundant
+        if not key_to_paths:
+            return item
+
+        result = dict(item)
+        for key, subpaths in key_to_paths.items():
+            if key in result:
+                result[key] = _deepcopy_with_paths(result[key], subpaths, index + 1)
+        return cast(_T, result)
+    if is_list(item):
+        array_paths = [path for path in paths if index < len(path) and path[index] == "<array>"]
+
+        # if no path expects a list here, nothing will be mutated inside it - return by reference
+        if not array_paths:
+            return cast(_T, item)
+        return cast(_T, [_deepcopy_with_paths(entry, array_paths, index + 1) for entry in item])
+    return item

src/anthropic/_utils/__init__.py

@@ -24,7 +24,6 @@
     coerce_integer as coerce_integer,
     file_from_path as file_from_path,
     strip_not_given as strip_not_given,
-    deepcopy_minimal as deepcopy_minimal,
     get_async_library as get_async_library,
     maybe_coerce_float as maybe_coerce_float,
     get_required_header as get_required_header,

src/anthropic/_utils/_utils.py

@@ -177,21 +177,6 @@ def is_iterable(obj: object) -> TypeGuard[Iterable[object]]:
     return isinstance(obj, Iterable)
 
 
-def deepcopy_minimal(item: _T) -> _T:
-    """Minimal reimplementation of copy.deepcopy() that will only copy certain object types:
-
-    - mappings, e.g. `dict`
-    - list
-
-    This is done for performance reasons.
-    """
-    if is_mapping(item):
-        return cast(_T, {k: deepcopy_minimal(v) for k, v in item.items()})
-    if is_list(item):
-        return cast(_T, [deepcopy_minimal(entry) for entry in item])
-    return item
-
-
 # copied from https://github.com/Rapptz/RoboDanny
 def human_join(seq: Sequence[str], *, delim: str = ", ", final: str = "or") -> str:
     size = len(seq)

src/anthropic/resources/beta/files.py

@@ -8,16 +8,9 @@
 import httpx
 
 from ... import _legacy_response
+from ..._files import deepcopy_with_paths
 from ..._types import Body, Omit, Query, Headers, NotGiven, FileTypes, omit, not_given
-from ..._utils import (
-    is_given,
-    extract_files,
-    path_template,
-    maybe_transform,
-    strip_not_given,
-    deepcopy_minimal,
-    async_maybe_transform,
-)
+from ..._utils import is_given, extract_files, path_template, maybe_transform, strip_not_given, async_maybe_transform
 from ..._compat import cached_property
 from ..._resource import SyncAPIResource, AsyncAPIResource
 from ..._response import (
@@ -326,7 +319,7 @@ def upload(
         }
         extra_headers = {"anthropic-beta": "files-api-2025-04-14", **(extra_headers or {})}
         extra_headers = {**_stainless_helper_header_from_file(file), **extra_headers}
-        body = deepcopy_minimal({"file": file})
+        body = deepcopy_with_paths({"file": file}, [["file"]])
         files = extract_files(cast(Mapping[str, object], body), paths=[["file"]])
         # It should be noted that the actual Content-Type header that will be
         # sent to the server will contain a `boundary` parameter, e.g.
@@ -626,7 +619,7 @@ async def upload(
         }
         extra_headers = {"anthropic-beta": "files-api-2025-04-14", **(extra_headers or {})}
         extra_headers = {**_stainless_helper_header_from_file(file), **extra_headers}
-        body = deepcopy_minimal({"file": file})
+        body = deepcopy_with_paths({"file": file}, [["file"]])
         files = extract_files(cast(Mapping[str, object], body), paths=[["file"]])
         # It should be noted that the actual Content-Type header that will be
         # sent to the server will contain a `boundary` parameter, e.g.

src/anthropic/resources/beta/skills/skills.py

@@ -16,6 +16,7 @@
     VersionsWithStreamingResponse,
     AsyncVersionsWithStreamingResponse,
 )
+from ...._files import deepcopy_with_paths
 from ...._types import (
     Body,
     Omit,
@@ -27,15 +28,7 @@
     omit,
     not_given,
 )
-from ...._utils import (
-    is_given,
-    extract_files,
-    path_template,
-    maybe_transform,
-    strip_not_given,
-    deepcopy_minimal,
-    async_maybe_transform,
-)
+from ...._utils import is_given, extract_files, path_template, maybe_transform, strip_not_given, async_maybe_transform
 from ...._compat import cached_property
 from ...._resource import SyncAPIResource, AsyncAPIResource
 from ...._response import to_streamed_response_wrapper, async_to_streamed_response_wrapper
@@ -123,11 +116,12 @@ def create(
             **(extra_headers or {}),
         }
         extra_headers = {"anthropic-beta": "skills-2025-10-02", **(extra_headers or {})}
-        body = deepcopy_minimal(
+        body = deepcopy_with_paths(
             {
                 "display_title": display_title,
                 "files": files,
-            }
+            },
+            [["files", "<array>"]],
         )
         extracted_files = extract_files(cast(Mapping[str, object], body), paths=[["files", "<array>"]])
         # It should be noted that the actual Content-Type header that will be
@@ -394,11 +388,12 @@ async def create(
             **(extra_headers or {}),
         }
         extra_headers = {"anthropic-beta": "skills-2025-10-02", **(extra_headers or {})}
-        body = deepcopy_minimal(
+        body = deepcopy_with_paths(
             {
                 "display_title": display_title,
                 "files": files,
-            }
+            },
+            [["files", "<array>"]],
         )
         extracted_files = extract_files(cast(Mapping[str, object], body), paths=[["files", "<array>"]])
         # It should be noted that the actual Content-Type header that will be

src/anthropic/resources/beta/skills/versions.py

@@ -8,6 +8,7 @@
 import httpx
 
 from .... import _legacy_response
+from ...._files import deepcopy_with_paths
 from ...._types import (
     Body,
     Omit,
@@ -19,15 +20,7 @@
     omit,
     not_given,
 )
-from ...._utils import (
-    is_given,
-    extract_files,
-    path_template,
-    maybe_transform,
-    strip_not_given,
-    deepcopy_minimal,
-    async_maybe_transform,
-)
+from ...._utils import is_given, extract_files, path_template, maybe_transform, strip_not_given, async_maybe_transform
 from ...._compat import cached_property
 from ...._resource import SyncAPIResource, AsyncAPIResource
 from ...._response import to_streamed_response_wrapper, async_to_streamed_response_wrapper
@@ -112,7 +105,7 @@ def create(
             **(extra_headers or {}),
         }
         extra_headers = {"anthropic-beta": "skills-2025-10-02", **(extra_headers or {})}
-        body = deepcopy_minimal({"files": files})
+        body = deepcopy_with_paths({"files": files}, [["files", "<array>"]])
         extracted_files = extract_files(cast(Mapping[str, object], body), paths=[["files", "<array>"]])
         # It should be noted that the actual Content-Type header that will be
         # sent to the server will contain a `boundary` parameter, e.g.
@@ -384,7 +377,7 @@ async def create(
             **(extra_headers or {}),
         }
         extra_headers = {"anthropic-beta": "skills-2025-10-02", **(extra_headers or {})}
-        body = deepcopy_minimal({"files": files})
+        body = deepcopy_with_paths({"files": files}, [["files", "<array>"]])
         extracted_files = extract_files(cast(Mapping[str, object], body), paths=[["files", "<array>"]])
         # It should be noted that the actual Content-Type header that will be
         # sent to the server will contain a `boundary` parameter, e.g.