feat: support shallow clone (#2653)

Support shallow cloning a dataset at a specific location to create a new
dataset, using the shallow_clone feature in Lance. Also introduce remote
`clone` API for remote tables for this functionality.

python/python/tests/test_db.py

@@ -831,3 +831,119 @@ def test_local_table_operations_with_namespace_raise_error(tmp_path):
     # Test table_names without namespace - should work normally
     tables_root = list(db.table_names())
     assert "test_table" in tables_root
+
+
+def test_clone_table_latest_version(tmp_path):
+    """Test cloning a table with the latest version (default behavior)"""
+    import os
+
+    db = lancedb.connect(tmp_path)
+
+    # Create source table with some data
+    data = [
+        {"id": 1, "text": "hello", "vector": [1.0, 2.0]},
+        {"id": 2, "text": "world", "vector": [3.0, 4.0]},
+    ]
+    source_table = db.create_table("source", data=data)
+
+    # Add more data to create a new version
+    more_data = [{"id": 3, "text": "test", "vector": [5.0, 6.0]}]
+    source_table.add(more_data)
+
+    # Clone the table (should get latest version with 3 rows)
+    source_uri = os.path.join(tmp_path, "source.lance")
+    cloned_table = db.clone_table("cloned", source_uri)
+
+    # Verify cloned table has all 3 rows
+    assert cloned_table.count_rows() == 3
+    assert "cloned" in db.table_names()
+
+    # Verify data matches
+    cloned_data = cloned_table.to_pandas()
+    assert len(cloned_data) == 3
+    assert set(cloned_data["id"].tolist()) == {1, 2, 3}
+
+
+def test_clone_table_specific_version(tmp_path):
+    """Test cloning a table from a specific version"""
+    import os
+
+    db = lancedb.connect(tmp_path)
+
+    # Create source table with initial data
+    data = [
+        {"id": 1, "text": "hello", "vector": [1.0, 2.0]},
+        {"id": 2, "text": "world", "vector": [3.0, 4.0]},
+    ]
+    source_table = db.create_table("source", data=data)
+
+    # Get the initial version
+    initial_version = source_table.version
+
+    # Add more data to create a new version
+    more_data = [{"id": 3, "text": "test", "vector": [5.0, 6.0]}]
+    source_table.add(more_data)
+
+    # Verify source now has 3 rows
+    assert source_table.count_rows() == 3
+
+    # Clone from the initial version (should have only 2 rows)
+    source_uri = os.path.join(tmp_path, "source.lance")
+    cloned_table = db.clone_table("cloned", source_uri, source_version=initial_version)
+
+    # Verify cloned table has only the initial 2 rows
+    assert cloned_table.count_rows() == 2
+    cloned_data = cloned_table.to_pandas()
+    assert set(cloned_data["id"].tolist()) == {1, 2}
+
+
+def test_clone_table_with_tag(tmp_path):
+    """Test cloning a table from a tagged version"""
+    import os
+
+    db = lancedb.connect(tmp_path)
+
+    # Create source table with initial data
+    data = [
+        {"id": 1, "text": "hello", "vector": [1.0, 2.0]},
+        {"id": 2, "text": "world", "vector": [3.0, 4.0]},
+    ]
+    source_table = db.create_table("source", data=data)
+
+    # Create a tag for the current version
+    source_table.tags.create("v1.0", source_table.version)
+
+    # Add more data after the tag
+    more_data = [{"id": 3, "text": "test", "vector": [5.0, 6.0]}]
+    source_table.add(more_data)
+
+    # Verify source now has 3 rows
+    assert source_table.count_rows() == 3
+
+    # Clone from the tagged version (should have only 2 rows)
+    source_uri = os.path.join(tmp_path, "source.lance")
+    cloned_table = db.clone_table("cloned", source_uri, source_tag="v1.0")
+
+    # Verify cloned table has only the tagged version's 2 rows
+    assert cloned_table.count_rows() == 2
+    cloned_data = cloned_table.to_pandas()
+    assert set(cloned_data["id"].tolist()) == {1, 2}
+
+
+def test_clone_table_deep_clone_fails(tmp_path):
+    """Test that deep clone raises an unsupported error"""
+    import os
+
+    db = lancedb.connect(tmp_path)
+
+    # Create source table with some data
+    data = [
+        {"id": 1, "text": "hello", "vector": [1.0, 2.0]},
+        {"id": 2, "text": "world", "vector": [3.0, 4.0]},
+    ]
+    db.create_table("source", data=data)
+
+    # Try to create a deep clone (should fail)
+    source_uri = os.path.join(tmp_path, "source.lance")
+    with pytest.raises(Exception, match="Deep clone is not yet implemented"):
+        db.clone_table("cloned", source_uri, is_shallow=False)