fix: better lists

src/arbor/cli.py

@@ -7,7 +7,7 @@
 from pathlib import Path
 
 from arbor.model import Asset, Grove
-from arbor.types import ArborError, VersionID
+from arbor.types import ArborError
 
 Command = Callable[[argparse.Namespace], None]
 
@@ -140,16 +140,6 @@ def _asset(args: argparse.Namespace) -> Asset:
     return _grove(args).asset(args.asset)
 
 
-def _selected_version(asset: Asset, version: VersionID | None) -> VersionID:
-    if version is not None:
-        return version
-    else:
-        latest = asset.latest_version()
-        if latest is None:
-            raise ArborError(f"{asset.asset_id} has no latest version")
-        return latest
-
-
 def _status(args: argparse.Namespace) -> None:
     grove = _grove(args)
     status = {"grove": str(grove.root), "filesystem": grove.fs.to_dict()}
@@ -221,8 +211,10 @@ def _download_dir(args: argparse.Namespace) -> None:
 
 def _validate_asset(args: argparse.Namespace) -> None:
     asset = _asset(args)
-    version = _selected_version(asset, args.version)
-    asset.grove.validate_version(asset.asset_id, version)
+    if args.version is None:
+        asset.validate()
+    else:
+        asset.grove.validate_version(asset.asset_id, args.version)
 
 
 def _print_lines(lines: Iterable[object]) -> None:

src/arbor/model.py

@@ -71,7 +71,8 @@ def read_log(self) -> list[dict[str, Any]]:
         return _parse_jsonl(self.dfs.read_text("log.jsonl"))
 
     def list_assets(self) -> list[AssetID]:
-        _, dirs, _ = next(self.dfs.walk("assets"))
+        # if assets/ is empty, walk() yields StopIteration; need a backstop
+        _, dirs, _ = next(self.dfs.walk("assets"), ("assets", [], []))
         return dirs
 
     def create_asset(self, asset_id: AssetID) -> Asset:
@@ -82,7 +83,7 @@ def create_asset(self, asset_id: AssetID) -> Asset:
 
         self.dfs.mkdir(asset_path)
 
-        manifest = dict()
+        manifest = {"latest_version": None}
         self._write_json(path=self._join([asset_path, "manifest.json"]), value=manifest)
         self.dfs.mkdir(self._join([asset_path, "versions"]))
         self._log_event({"event": "create_asset", "asset_id": asset_id})
@@ -197,7 +198,8 @@ def list_data(self, asset_id: AssetID, version: VersionID | None) -> list[str]:
     def list_versions(self, asset_id: AssetID) -> list[VersionID]:
         self._require_asset(asset_id)
         _, dir_names, _ = next(
-            self.dfs.walk(self._join(["assets", asset_id, "versions"]))
+            self.dfs.walk(self._join(["assets", asset_id, "versions"])),
+            ("versions", [], []),
         )
         return dir_names
 
@@ -212,7 +214,7 @@ def _latest_version_required(self, asset_id: AssetID) -> VersionID:
         if v is not None:
             return v
         else:
-            raise ArborError(f"{asset_id} has no latest version")
+            raise ArborError(f"{asset_id} has no versions")
 
     def _upload(
         self,
@@ -255,9 +257,9 @@ def _upload(
                 self.dfs.makedirs(parent, exist_ok=True)
                 self.dfs.put_file(str(source), destination)
 
-            self._write_json(path=asset_manifest_path, value=asset_manifest)
             self._write_json(path=version_manifest_path, value=version_manifest)
             self._log_event({"event": "upload", "asset": asset_id, "version": version})
+            self._write_json(path=asset_manifest_path, value=asset_manifest)
         except BaseException:
             self.dfs.rm(version_path, recursive=True)
             raise

tests/conftest.py

@@ -33,6 +33,9 @@ def filesystem_lifecycle():
     """Return an assertion covering the filesystem operations Arbor requires."""
 
     def assert_complete(grove: Grove, tmp_path: Path) -> None:
+        assert grove.list_assets() == []
+        grove.validate()
+
         file_source = tmp_path / "moby.txt"
         file_source.write_text("Call me Ishmael")
 
@@ -43,6 +46,16 @@ def assert_complete(grove: Grove, tmp_path: Path) -> None:
         (dir_source / "books" / "moby.txt").write_text("Call me Ishmael")
 
         asset = grove.create_asset("myasset")
+        assert asset.list_versions() == []
+        assert asset.latest_version() is None
+        asset.validate()
+        with pytest.raises(ArborError, match="has no versions"):
+            asset.list_data()
+        with pytest.raises(ArborError, match="has no versions"):
+            asset.mode()
+        with pytest.raises(ArborError, match="has no versions"):
+            asset.metadata()
+
         first_version = asset.upload_file(file_source, metadata={"author": "Melville"})
 
         assert grove.list_assets() == ["myasset"]

tests/test_cli.py

@@ -41,6 +41,16 @@ def my_run(argv):
     assert my_run(["setup"]) == 0
     assert my_run(["create", "my-asset"]) == 0
 
+    assert my_run(["asset", "my-asset", "list-versions"]) == 0
+    assert my_run(["asset", "my-asset", "latest-version"]) == 0
+    assert my_run(["asset", "my-asset", "validate"]) == 0
+    assert capsys.readouterr().out == ""
+
+    assert my_run(["asset", "my-asset", "list-data"]) == 2
+    captured = capsys.readouterr()
+    assert captured.out == ""
+    assert captured.err == "arbor: my-asset has no versions\n"
+
     source = tmp_path / "data.csv"
     source.write_text("x\n1\n")
     metadata = {"source": "cli", "rows": 1}