TMP: Give meta-dump basic parameter constraints from next

This adds an 'EnsureDataset()' parameter validation, and an 'EnsureStr()'
parameter validation for the path argument.
The immediate advantage is that there are now distinct errors for
NoMetaDataStoreFound and NoDatasetFound, which were prior both resulting
in a NoMetaDataStoreFound exception.

datalad_metalad/dump.py

@@ -27,14 +27,18 @@
 
 from datalad.distribution.dataset import datasetmethod
 from datalad.interface.base import (
-    Interface,
     build_doc,
     eval_results,
 )
-from datalad.support.constraints import (
-    EnsureNone,
+from datalad_next.commands import (
+    EnsureCommandParameterization,
+    ValidatedInterface,
+)
+from datalad_next.constraints import (
     EnsureStr,
+    EnsureNone,
 )
+from datalad_next.constraints.dataset import EnsureDataset
 from datalad.support.param import Parameter
 from datalad.ui import ui
 from dataladmetadatamodel.datasettree import datalad_root_record_name
@@ -413,7 +417,7 @@ def dump_from_uuid_set(mapper: str,
 
 
 @build_doc
-class Dump(Interface):
+class Dump(ValidatedInterface):
     """Dump a dataset's aggregated metadata for dataset and file metadata
 
     Two types of metadata are supported:
@@ -432,6 +436,16 @@ class Dump(Interface):
     (The tree-format is the default format and does not require a prefix).
     """
 
+    # Define parameter constraints
+    _validator_ = EnsureCommandParameterization(
+        param_constraints=dict(
+            dataset=EnsureDataset(installed=True, purpose='meta-dump'),
+            path=EnsureStr(),
+        ),
+        validate_defaults=("dataset",)
+    )
+
+
     # Use a custom renderer to emit a self-contained metadata record. The
     # emitted record can be fed into meta-add for example.
     result_renderer = 'tailored'
@@ -481,7 +495,6 @@ class Dump(Interface):
             args=("path",),
             metavar="DATASET_FILE_PATH_PATTERN",
             doc="path to query metadata for",
-            constraints=EnsureStr() | EnsureNone(),
             nargs="?"),
         recursive=Parameter(
             args=("-r", "--recursive",),
@@ -501,6 +514,8 @@ def __call__(
             path="",
             recursive=False):
 
+        # dataset is a DatasetParameter() from datalad-next
+        dataset = dataset.ds.path
         metadata_store_path, tree_version_list, uuid_set = get_metadata_objects(
             dataset,
             default_mapper_family)