Update DataTree repr to indicate inheritance (pydata#9470)

* Update DataTree repr to indicate inheritance

Fixes pydata#9463

* fix whitespace

* add more repr tests, fix failure

* fix failure on windows

* fix repr for inherited dimensions

asv_bench/benchmarks/datatree.py

@@ -6,7 +6,7 @@ class Datatree:
     def setup(self):
         run1 = DataTree.from_dict({"run1": xr.Dataset({"a": 1})})
         self.d_few = {"run1": run1}
-        self.d_many = {f"run{i}": run1.copy() for i in range(100)}
+        self.d_many = {f"run{i}": xr.Dataset({"a": 1}) for i in range(100)}
 
     def time_from_dict_few(self):
         DataTree.from_dict(self.d_few)

xarray/core/formatting.py

@@ -6,13 +6,13 @@
 import contextlib
 import functools
 import math
-from collections import defaultdict
-from collections.abc import Collection, Hashable, Sequence
+from collections import ChainMap, defaultdict
+from collections.abc import Collection, Hashable, Mapping, Sequence
 from datetime import datetime, timedelta
 from itertools import chain, zip_longest
 from reprlib import recursive_repr
 from textwrap import dedent
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 import numpy as np
 import pandas as pd
@@ -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,
@@ -571,8 +587,10 @@ def _element_formatter(
     return "".join(out)
 
 
-def dim_summary_limited(obj, col_width: int, max_rows: int | None = None) -> str:
-    elements = [f"{k}: {v}" for k, v in obj.sizes.items()]
+def dim_summary_limited(
+    sizes: Mapping[Any, int], col_width: int, max_rows: int | None = None
+) -> str:
+    elements = [f"{k}: {v}" for k, v in sizes.items()]
     return _element_formatter(elements, col_width, max_rows)
 
 
@@ -676,7 +694,7 @@ def array_repr(arr):
         data_repr = inline_variable_array_repr(arr.variable, OPTIONS["display_width"])
 
     start = f"<xarray.{type(arr).__name__} {name_str}"
-    dims = dim_summary_limited(arr, col_width=len(start) + 1, max_rows=max_rows)
+    dims = dim_summary_limited(arr.sizes, col_width=len(start) + 1, max_rows=max_rows)
     nbytes_str = render_human_readable_nbytes(arr.nbytes)
     summary = [
         f"{start}({dims})> Size: {nbytes_str}",
@@ -721,7 +739,9 @@ def dataset_repr(ds):
     max_rows = OPTIONS["display_max_rows"]
 
     dims_start = pretty_print("Dimensions:", col_width)
-    dims_values = dim_summary_limited(ds, col_width=col_width + 1, max_rows=max_rows)
+    dims_values = dim_summary_limited(
+        ds.sizes, col_width=col_width + 1, max_rows=max_rows
+    )
     summary.append(f"{dims_start}({dims_values})")
 
     if ds.coords:
@@ -756,7 +776,9 @@ def dims_and_coords_repr(ds) -> str:
     max_rows = OPTIONS["display_max_rows"]
 
     dims_start = pretty_print("Dimensions:", col_width)
-    dims_values = dim_summary_limited(ds, col_width=col_width + 1, max_rows=max_rows)
+    dims_values = dim_summary_limited(
+        ds.sizes, col_width=col_width + 1, max_rows=max_rows
+    )
     summary.append(f"{dims_start}({dims_values})")
 
     if ds.coords:
@@ -1050,39 +1072,95 @@ 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
+    )
+
+    dim_sizes = node.sizes if show_inherited else node._node_dims
+
+    if show_dims:
+        # Includes inherited dimensions.
+        dims_start = pretty_print("Dimensions:", col_width)
+        dims_values = dim_summary_limited(
+            dim_sizes, col_width=col_width + 1, max_rows=max_rows
+        )
+        summary.append(f"{dims_start}({dims_values})")
+
+    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(
+            dim_sizes, 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))
 
-def datatree_repr(dt: DataTree):
+    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
+
+        raw_repr_lines = node_repr.splitlines()
 
-        node_line = f"{pre}{node_repr.splitlines()[0]}"
+        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)