Replace Literal zarr_mode with ZarrMode(str, Enum)

Follow existing codebase pattern (UploadExisting, DownloadExisting, etc.)
to define ZarrMode as a str Enum in upload.py.  Eliminates the duplicated
Literal["full", "patch"] across three files and the cast() workaround in
cmd_upload.py.

Uses TYPE_CHECKING guard in files/zarr.py to avoid circular import
(files/zarr.py -> upload.py -> .files).

Co-Authored-By: Claude Code 2.1.63 / Claude Opus 4.6 <noreply@anthropic.com>

Author: yarikoptic

dandi/cli/cmd_upload.py

@@ -1,7 +1,5 @@
 from __future__ import annotations
 
-from typing import Literal, cast
-
 import click
 
 from .base import (
@@ -11,7 +9,7 @@
     instance_option,
     map_to_click_exceptions,
 )
-from ..upload import UploadExisting, UploadValidation
+from ..upload import UploadExisting, UploadValidation, ZarrMode
 
 
 @click.command()
@@ -52,7 +50,7 @@
 )
 @click.option(
     "--zarr-mode",
-    type=click.Choice(["full", "patch"]),
+    type=click.Choice(list(ZarrMode)),
     default="full",
     help=(
         "Zarr sync mode: 'full' (default) syncs completely; "
@@ -87,7 +85,7 @@ def upload(
     dandi_instance: str,
     existing: UploadExisting,
     validation: UploadValidation,
-    zarr_mode: str,
+    zarr_mode: ZarrMode,
     # Development options should come as kwargs
     allow_any_path: bool = False,
     upload_dandiset_metadata: bool = False,
@@ -128,5 +126,5 @@ def upload(
         jobs=jobs,
         jobs_per_file=jobs_per_file,
         sync=sync,
-        zarr_mode=cast(Literal["full", "patch"], zarr_mode),
+        zarr_mode=zarr_mode,
     )

dandi/files/zarr.py

@@ -12,7 +12,10 @@
 import os.path
 from pathlib import Path
 from time import sleep
-from typing import Any, Literal, Optional
+from typing import TYPE_CHECKING, Any, Optional
+
+if TYPE_CHECKING:
+    from ..upload import ZarrMode
 import urllib.parse
 
 from dandischema.models import BareAsset, DigestType
@@ -557,7 +560,7 @@ def iter_upload(
         metadata: dict[str, Any],
         jobs: int | None = None,
         replacing: RemoteAsset | None = None,
-        zarr_mode: Literal["full", "patch"] = "full",
+        zarr_mode: ZarrMode = "full",  # type: ignore[assignment]
     ) -> Iterator[dict]:
         """
         Upload the Zarr directory as an asset with the given metadata to the

dandi/upload.py

@@ -21,7 +21,7 @@
 import re
 import time
 from time import sleep
-from typing import Any, Literal, TypedDict, cast
+from typing import Any, TypedDict, cast
 from unittest.mock import patch
 
 import click
@@ -101,6 +101,14 @@ def __str__(self) -> str:
         return self.value
 
 
+class ZarrMode(str, Enum):
+    FULL = "full"
+    PATCH = "patch"
+
+    def __str__(self) -> str:
+        return self.value
+
+
 def upload(
     paths: Sequence[str | Path] | None = None,
     existing: UploadExisting = UploadExisting.REFRESH,
@@ -112,7 +120,7 @@ def upload(
     jobs: int | None = None,
     jobs_per_file: int | None = None,
     sync: bool = False,
-    zarr_mode: Literal["full", "patch"] = "full",
+    zarr_mode: ZarrMode = ZarrMode.FULL,
 ) -> None:
     if paths:
         paths = [Path(p).absolute() for p in paths]