Made UniqueDotExporter output deterministic

Changed from python object ids to a simple counter as DOT node name. This way identical trees will produce identical DOT output, regardless of their location in memory. Doctests now work too, because the output does not vary anymore.
c0fec0de · Mar 11, 2022 · aab1dc0 · aab1dc0
1 parent d63289b
commit aab1dc0
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Showing 2 changed files with 40 additions and 39 deletions.
diff --git a/anytree/exporter/dotexporter.py b/anytree/exporter/dotexporter.py
@@ -1,4 +1,5 @@
 import codecs
+import itertools
 import logging
 import re
 from os import path
@@ -334,26 +335,26 @@ def __init__(self, node, graph="digraph", name="tree", options=None,
         >>> s1ca = Node("sub1Ca", parent=s1c)
 
         >>> from anytree.exporter import UniqueDotExporter
-        >>> for line in UniqueDotExporter(root):  # doctest: +SKIP
+        >>> for line in UniqueDotExporter(root):
         ...     print(line)
         digraph tree {
-            "0x7f1bf2c9c510" [label="root"];
-            "0x7f1bf2c9c5a0" [label="sub0"];
-            "0x7f1bf2c9c630" [label="s0"];
-            "0x7f1bf2c9c6c0" [label="s0"];
-            "0x7f1bf2c9c750" [label="sub1"];
-            "0x7f1bf2c9c7e0" [label="s1"];
-            "0x7f1bf2c9c870" [label="s1"];
-            "0x7f1bf2c9c900" [label="s1"];
-            "0x7f1bf2c9c990" [label="sub1Ca"];
-            "0x7f1bf2c9c510" -> "0x7f1bf2c9c5a0";
-            "0x7f1bf2c9c510" -> "0x7f1bf2c9c750";
-            "0x7f1bf2c9c5a0" -> "0x7f1bf2c9c630";
-            "0x7f1bf2c9c5a0" -> "0x7f1bf2c9c6c0";
-            "0x7f1bf2c9c750" -> "0x7f1bf2c9c7e0";
-            "0x7f1bf2c9c750" -> "0x7f1bf2c9c870";
-            "0x7f1bf2c9c750" -> "0x7f1bf2c9c900";
-            "0x7f1bf2c9c900" -> "0x7f1bf2c9c990";
+            "0" [label="root"];
+            "1" [label="sub0"];
+            "2" [label="s0"];
+            "3" [label="s0"];
+            "4" [label="sub1"];
+            "5" [label="s1"];
+            "6" [label="s1"];
+            "7" [label="s1"];
+            "8" [label="sub1Ca"];
+            "0" -> "1";
+            "0" -> "4";
+            "1" -> "2";
+            "1" -> "3";
+            "4" -> "5";
+            "4" -> "6";
+            "4" -> "7";
+            "7" -> "8";
         }
 
         The resulting graph:
@@ -369,25 +370,29 @@ def __init__(self, node, graph="digraph", name="tree", options=None,
         >>> s0a = AnyNode(id="s0", parent=s0)
 
         >>> from anytree.exporter import UniqueDotExporter
-        >>> for line in UniqueDotExporter(root, nodeattrfunc=lambda n: 'label="%s"' % (n.id)):  # doctest: +SKIP
+        >>> for line in UniqueDotExporter(root, nodeattrfunc=lambda n: 'label="%s"' % (n.id)):
         ...     print(line)
         digraph tree {
-            "0x7f5c70449af8" [label="root"];
-            "0x7f5c70449bd0" [label="sub0"];
-            "0x7f5c70449c60" [label="s0"];
-            "0x7f5c70449cf0" [label="s0"];
-            "0x7f5c70449af8" -> "0x7f5c70449bd0";
-            "0x7f5c70449bd0" -> "0x7f5c70449c60";
-            "0x7f5c70449bd0" -> "0x7f5c70449cf0";
+            "0" [label="root"];
+            "1" [label="sub0"];
+            "2" [label="s0"];
+            "3" [label="s0"];
+            "0" -> "1";
+            "1" -> "2";
+            "1" -> "3";
         }
         """
         super(UniqueDotExporter, self).__init__(node, graph=graph, name=name, options=options, indent=indent,
                                                 nodenamefunc=nodenamefunc, nodeattrfunc=nodeattrfunc,
                                                 edgeattrfunc=edgeattrfunc, edgetypefunc=edgetypefunc)
-
-    @staticmethod
-    def _default_nodenamefunc(node):
-        return hex(id(node))
+        self.node_ids = {}
+        self.node_counter = itertools.count()
+
+    def _default_nodenamefunc(self, node):
+        node_id = id(node)
+        if node_id not in self.node_ids:
+            self.node_ids[node_id] = next(self.node_counter)
+        return self.node_ids[id(node)]
 
     @staticmethod
     def _default_nodeattrfunc(node):

diff --git a/tests/test_uniquedotexporter.py b/tests/test_uniquedotexporter.py
@@ -19,15 +19,11 @@ def test_tree1():
     s0 = Node("sub0", parent=root)
     s0b = Node("sub0B", parent=s0)
 
-    id_root = hex(id(root))
-    id_s0 = hex(id(s0))
-    id_s0b = hex(id(s0b))
-
     lines = tuple(UniqueDotExporter(root))
     eq_(lines, ('digraph tree {',
-                '    "{id_root}" [label="root"];'.format(id_root=id_root),
-                '    "{id_s0}" [label="sub0"];'.format(id_s0=id_s0),
-                '    "{id_s0b}" [label="sub0B"];'.format(id_s0b=id_s0b),
-                '    "{id_root}" -> "{id_s0}";'.format(id_root=id_root, id_s0=id_s0),
-                '    "{id_s0}" -> "{id_s0b}";'.format(id_s0=id_s0, id_s0b=id_s0b),
+                '    "0" [label="root"];',
+                '    "1" [label="sub0"];',
+                '    "2" [label="sub0B"];',
+                '    "0" -> "1";',
+                '    "1" -> "2";',
                 '}'))