Add --yes/-y flag to dandi download for headless sync usage

When using `dandi download --sync`, the CLI prompts for confirmation
before deleting local assets not found on the server. This fails in
headless environments (CI/CD, cron jobs) where no interactive terminal
is available. The new `--yes` / `-y` flag auto-confirms such prompts.

Closes #1833

https://claude.ai/code/session_01297X1VGdztFArkpVFB1zEk

Author: claude

dandi/cli/cmd_download.py

@@ -118,6 +118,12 @@
 @click.option(
     "--sync", is_flag=True, help="Delete local assets that do not exist on the server"
 )
+@click.option(
+    "-y",
+    "--yes",
+    is_flag=True,
+    help="Automatically confirm yes to any prompts (e.g., deletion with --sync)",
+)
 @instance_option(
     default=None,
     help=(
@@ -151,6 +157,7 @@ def download(
     format: DownloadFormat,
     download_types: set[str],
     sync: bool,
+    yes: bool,
     dandi_instance: str,
     path_type: PathType,
     preserve_tree: bool,
@@ -191,6 +198,7 @@ def download(
         get_assets="assets" in download_types or preserve_tree,
         preserve_tree=preserve_tree,
         sync=sync,
+        yes=yes,
         path_type=path_type,
         # develop_debug=develop_debug
     )

dandi/download.py

@@ -108,6 +108,7 @@ def download(
     get_assets: bool = True,
     preserve_tree: bool = False,
     sync: bool = False,
+    yes: bool = False,
     path_type: PathType = PathType.EXACT,
 ) -> None:
     # TODO: unduplicate with upload. For now stole from that one
@@ -204,25 +205,31 @@ def p4e(out):
     if sync:
         to_delete = [p for dl in downloaders for p in dl.delete_for_sync()]
         if to_delete:
-            while True:
-                opt = abbrev_prompt(
-                    f"Delete {pluralize(len(to_delete), 'local asset')}?",
-                    "yes",
-                    "no",
-                    "list",
-                )
-                if opt == "list":
-                    for p in to_delete:
-                        print(p)
-                elif opt == "yes":
-                    for p in to_delete:
-                        if p.is_dir():
-                            rmtree(p)
-                        else:
-                            p.unlink()
-                    break
-                else:
-                    break
+            do_delete = False
+            if yes:
+                do_delete = True
+            else:
+                while True:
+                    opt = abbrev_prompt(
+                        f"Delete {pluralize(len(to_delete), 'local asset')}?",
+                        "yes",
+                        "no",
+                        "list",
+                    )
+                    if opt == "list":
+                        for p in to_delete:
+                            print(p)
+                    elif opt == "yes":
+                        do_delete = True
+                        break
+                    else:
+                        break
+            if do_delete:
+                for p in to_delete:
+                    if p.is_dir():
+                        rmtree(p)
+                    else:
+                        p.unlink()
     if errors:
         error_msg = f"Encountered {pluralize(len(errors), 'error')} while downloading."
         # Also log the first error for easier debugging

dandi/tests/test_download.py

@@ -319,6 +319,25 @@ def test_download_sync(
         assert (dspath / "file.txt").exists()
 
 
+@pytest.mark.ai_generated
+def test_download_sync_yes(
+    mocker: MockerFixture, text_dandiset: SampleDandiset, tmp_path: Path
+) -> None:
+    text_dandiset.dandiset.get_asset_by_path("file.txt").delete()
+    dspath = tmp_path / text_dandiset.dandiset_id
+    os.rename(text_dandiset.dspath, dspath)
+    confirm_mock = mocker.patch("dandi.download.abbrev_prompt")
+    download(
+        f"dandi://{text_dandiset.api.instance_id}/{text_dandiset.dandiset_id}",
+        tmp_path,
+        existing=DownloadExisting.OVERWRITE,
+        sync=True,
+        yes=True,
+    )
+    confirm_mock.assert_not_called()
+    assert not (dspath / "file.txt").exists()
+
+
 def test_download_sync_folder(
     mocker: MockerFixture, text_dandiset: SampleDandiset
 ) -> None: