Update DataTree repr to indicate inheritance

Fixes pydata#9463

xarray/core/formatting.py

@@ -6,7 +6,7 @@
 import contextlib
 import functools
 import math
-from collections import defaultdict
+from collections import ChainMap, defaultdict
 from collections.abc import Collection, Hashable, Sequence
 from datetime import datetime, timedelta
 from itertools import chain, zip_longest
@@ -29,6 +29,7 @@
 if TYPE_CHECKING:
     from xarray.core.coordinates import AbstractCoordinates
     from xarray.core.datatree import DataTree
+    from xarray.core.variable import Variable
 
 UNITS = ("B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
 
@@ -318,7 +319,7 @@ def inline_variable_array_repr(var, max_width):
 
 def summarize_variable(
     name: Hashable,
-    var,
+    var: Variable,
     col_width: int,
     max_width: int | None = None,
     is_index: bool = False,
@@ -446,6 +447,21 @@ def coords_repr(coords: AbstractCoordinates, col_width=None, max_rows=None):
     )
 
 
+def inherited_coords_repr(node: DataTree, col_width=None, max_rows=None):
+    coords = _inherited_vars(node._coord_variables)
+    if col_width is None:
+        col_width = _calculate_col_width(coords)
+    return _mapping_repr(
+        coords,
+        title="Inherited coordinates",
+        summarizer=summarize_variable,
+        expand_option_name="display_expand_coords",
+        col_width=col_width,
+        indexes=node._indexes,
+        max_rows=max_rows,
+    )
+
+
 def inline_index_repr(index: pd.Index, max_width=None):
     if hasattr(index, "_repr_inline_"):
         repr_ = index._repr_inline_(max_width=max_width)
@@ -498,12 +514,12 @@ def filter_nondefault_indexes(indexes, filter_indexes: bool):
     }
 
 
-def indexes_repr(indexes, max_rows: int | None = None) -> str:
+def indexes_repr(indexes, max_rows: int | None = None, title: str = "Indexes") -> str:
     col_width = _calculate_col_width(chain.from_iterable(indexes))
 
     return _mapping_repr(
         indexes,
-        "Indexes",
+        title,
         summarize_index,
         "display_expand_indexes",
         col_width=col_width,
@@ -1048,39 +1064,93 @@ def diff_datatree_repr(a: DataTree, b: DataTree, compat):
     return "\n".join(summary)
 
 
-def _single_node_repr(node: DataTree) -> str:
-    """Information about this node, not including its relationships to other nodes."""
-    if node.has_data or node.has_attrs:
-        # TODO: change this to inherited=False, in order to clarify what is
-        # inherited? https://github.com/pydata/xarray/issues/9463
-        node_view = node._to_dataset_view(rebuild_dims=False, inherited=True)
-        ds_info = "\n" + repr(node_view)
-    else:
-        ds_info = ""
-    return f"Group: {node.path}{ds_info}"
+def _inherited_vars(mapping: ChainMap) -> dict:
+    return {k: v for k, v in mapping.parents.items() if k not in mapping.maps[0]}
+
+
+def _datatree_node_repr(node: DataTree, show_inherited: bool) -> str:
+    summary = [f"Group: {node.path}"]
+
+    col_width = _calculate_col_width(node.variables)
+    max_rows = OPTIONS["display_max_rows"]
+
+    inherited_coords = _inherited_vars(node._coord_variables)
 
+    # Only show dimensions if also showing a variable or coordinates section.
+    show_dims = (
+        node._node_coord_variables
+        or (show_inherited and inherited_coords)
+        or node._data_variables
+    )
+
+    if show_dims:
+        # Includes inherited dimensions.
+        dims_start = pretty_print("Dimensions:", col_width)
+        dims_values = dim_summary_limited(
+            node, col_width=col_width + 1, max_rows=max_rows
+        )
+        summary.append(f"{dims_start}({dims_values})")
 
-def datatree_repr(dt: DataTree):
+    if node._node_coord_variables:
+        summary.append(coords_repr(node.coords, col_width=col_width, max_rows=max_rows))
+
+    if show_inherited and inherited_coords:
+        summary.append(
+            inherited_coords_repr(node, col_width=col_width, max_rows=max_rows)
+        )
+
+    if show_dims:
+        unindexed_dims_str = unindexed_dims_repr(
+            node.dims, node.coords, max_rows=max_rows
+        )
+        if unindexed_dims_str:
+            summary.append(unindexed_dims_str)
+
+    if node._data_variables:
+        summary.append(
+            data_vars_repr(node._data_variables, col_width=col_width, max_rows=max_rows)
+        )
+
+    # TODO: only show indexes defined at this node, with a separate section for
+    # inherited indexes (if show_inherited=True)
+    display_default_indexes = _get_boolean_with_default(
+        "display_default_indexes", False
+    )
+    xindexes = filter_nondefault_indexes(
+        _get_indexes_dict(node.xindexes), not display_default_indexes
+    )
+    if xindexes:
+        summary.append(indexes_repr(xindexes, max_rows=max_rows))
+
+    if node.attrs:
+        summary.append(attrs_repr(node.attrs, max_rows=max_rows))
+
+    return "\n".join(summary)
+
+
+def datatree_repr(dt: DataTree) -> str:
     """A printable representation of the structure of this entire tree."""
     renderer = RenderDataTree(dt)
 
     name_info = "" if dt.name is None else f" {dt.name!r}"
     header = f"<xarray.DataTree{name_info}>"
 
     lines = [header]
+    show_inherited = True
     for pre, fill, node in renderer:
-        node_repr = _single_node_repr(node)
+        node_repr = _datatree_node_repr(node, show_inherited=show_inherited)
+        show_inherited = False  # only show inherited coords on the root
 
-        node_line = f"{pre}{node_repr.splitlines()[0]}"
+        raw_repr_lines = node_repr.splitlines()
+
+        node_line = f"{pre}{raw_repr_lines[0]}"
         lines.append(node_line)
 
-        if node.has_data or node.has_attrs:
-            ds_repr = node_repr.splitlines()[2:]
-            for line in ds_repr:
-                if len(node.children) > 0:
-                    lines.append(f"{fill}{renderer.style.vertical}{line}")
-                else:
-                    lines.append(f"{fill}{' ' * len(renderer.style.vertical)}{line}")
+        for line in raw_repr_lines[1:]:
+            if len(node.children) > 0:
+                lines.append(f"{fill}{renderer.style.vertical}{line}")
+            else:
+                lines.append(f"{fill}{' ' * len(renderer.style.vertical)}{line}")
 
     return "\n".join(lines)
 

xarray/tests/test_datatree.py

@@ -798,20 +798,16 @@ def test_repr(self):
             │       e        (x) float64 16B 1.0 2.0
             └── Group: /b
                 │   Dimensions:  (x: 2, y: 1)
-                │   Coordinates:
-                │     * x        (x) float64 16B 2.0 3.0
                 │   Dimensions without coordinates: y
                 │   Data variables:
                 │       f        (y) float64 8B 3.0
                 ├── Group: /b/c
                 └── Group: /b/d
                         Dimensions:  (x: 2, y: 1)
-                        Coordinates:
-                          * x        (x) float64 16B 2.0 3.0
                         Dimensions without coordinates: y
                         Data variables:
                             g        float64 8B 4.0
-            """
+                        """
         ).strip()
         assert result == expected
 
@@ -821,16 +817,14 @@ def test_repr(self):
             <xarray.DataTree 'b'>
             Group: /b
             │   Dimensions:  (x: 2, y: 1)
-            │   Coordinates:
+            │   Inherited coordinates:
             │     * x        (x) float64 16B 2.0 3.0
             │   Dimensions without coordinates: y
             │   Data variables:
             │       f        (y) float64 8B 3.0
             ├── Group: /b/c
             └── Group: /b/d
                     Dimensions:  (x: 2, y: 1)
-                    Coordinates:
-                      * x        (x) float64 16B 2.0 3.0
                     Dimensions without coordinates: y
                     Data variables:
                         g        float64 8B 4.0