fix ordered() crash on grobs and silent dotted-path failures

plotdevice · samizdatco · Jul 9, 2026 · Jul 9, 2026 · Jul 9, 2026 · Jul 9, 2026
commit 665bc579bf7e1d868deb69b0a22e15660f06b8ed
diff --git a/plotdevice/util/__init__.py b/plotdevice/util/__init__.py
@@ -5,8 +5,9 @@
 import json
 import csv
 from contextlib import contextmanager
-from functools import cmp_to_key
+from functools import cmp_to_key, reduce
 from collections import OrderedDict, defaultdict
+from collections.abc import Mapping
 from os.path import abspath, dirname, exists, join, splitext
 from random import choice, shuffle
 
@@ -106,18 +107,15 @@ def _key(seq, names):
     # treat objects without a given key and objects with the key set to None equivalently
     MISSING = None
 
-    # look for dict items by default
-    getter = lambda obj: tuple(obj.get(n, MISSING) for n in names)
+    def getter(obj):
+        # use item lookup if obj is dict-like
+        if isinstance(obj, Mapping):
+            return tuple(obj.get(n, MISSING) for n in names)
 
-    # walk through the objects and see if any of them lacks the dict fields but has attrs
-    for obj in seq:
-        try:
-            if any(n in obj for n in names):
-                break # dict fields exist so use the itemgetter
-        except TypeError:
-            # for non-dict objects like namedtuples and dataclasses use an attrgetter
-            if any(hasattr(obj, n) for n in names):
-                getter = lambda obj: tuple(getattr(obj, n, MISSING) for n in names)
+        # otherwise check attrs
+        return tuple(
+            reduce(lambda o, part: getattr(o, part, MISSING), n.split('.'), obj) for n in names
+        )
 
     def compare(a, b):
         default = 0

diff --git a/tests/__init__.py b/tests/__init__.py
@@ -70,10 +70,10 @@ def render(self, save_output=True):
   pass
 
 def suites():
-  from . import typography, primitives, drawing, compositing, geometry, module
+  from . import typography, primitives, drawing, compositing, geometry, module, canvas
 
   suite = unittest.TestSuite()
-  for mod in (typography, primitives, drawing, compositing, geometry, module):
+  for mod in (typography, primitives, drawing, compositing, geometry, module, canvas):
     suite.addTest(mod.suite())
   return suite
 

diff --git a/tests/canvas.py b/tests/canvas.py
@@ -0,0 +1,32 @@
+# encoding: utf-8
+import unittest
+from types import SimpleNamespace
+from collections import UserDict
+from . import PlotDeviceTestCase
+from plotdevice import *
+
+class CanvasTests(PlotDeviceTestCase):
+    def test_ordered_by_dotted_attr(self):
+        size(100, 100)
+        positions = [80, 20, 50]
+        for y in positions:
+            rect(10, y, 10, 10)
+
+        sorted_grobs = ordered(canvas, 'bounds.y')
+        self.assertEqual([g.bounds.y for g in sorted_grobs], sorted(positions))
+
+    def test_ordered_by_dict_like_non_dict(self):
+        items = [UserDict({'y': 80}), UserDict({'y': 20}), UserDict({'y': 50})]
+        sorted_items = ordered(items, 'y')
+        self.assertEqual([d['y'] for d in sorted_items], [20, 50, 80])
+
+    def test_ordered_heterogeneous_items(self):
+        items = [{'y': 80}, SimpleNamespace(y=20), {'y': 50}]
+        sorted_items = ordered(items, 'y')
+        ys = [it['y'] if isinstance(it, dict) else it.y for it in sorted_items]
+        self.assertEqual(ys, [20, 50, 80])
+
+def suite():
+    suite = unittest.TestSuite()
+    suite.addTest(unittest.defaultTestLoader.loadTestsFromTestCase(CanvasTests))
+    return suite