Fix dot file generation

This commit fixes a regression introduced in Qiskit#1203. That PR was
attempting to fix missing character escaping in some string fields
but it was doing so too eagerly. This would result in invalid dot
files being produced for users upgrading from rustworkx < 0.15.0 that
were wrapping strings in quotes as needed previously. For example if you
were setting `'color="#aaaaaa"'` previously before this would become
`color="\"#aaaaaa\""` after Qiskit#1203. In order to quickly release a 0.15.1
this commit reverts the dot generation component of Qiskit#1203 but updates
the code to wrap tooltip in addition to label which was what the
original bug reported. In 0.16.0 we should investigate adding a flag to
control the escaping behavior of the function to either decide to wrap
values in quotes or not.

releasenotes/notes/fix-graphviz-escaping-39a2d1cebb586eca.yaml

@@ -0,0 +1,21 @@
+---
+fixes:
+  - |
+    Fixed an issue in the :func:`~.graphviz_draw`, :meth:`.PyGraph.to_dot`, and
+    :meth:`.PyDiGraph.to_dot` which was incorrectly escaping strings when
+    upgrading to 0.15.0. In earlier versions of rustworkx if you manually
+    placed quotes in a string for an attr callback get that to pass through to 
+    the output dot file this was incorrectly being converted in rustworkx 0.15.0
+    to duplicate the quotes and escape them. For example, if you defined a
+    callback like::
+
+        def color_node(_node):
+            return {
+                "color": '"#422952"'
+            }
+    to set the color attribute in the output dot file with the string
+    `"#422952"` (with the quotes) this was incorrectly being converted to
+    `\"#422952\"`. This no longer occurs, in rustworkx 0.16.0 there will likely
+    be additional options exposed in :func:`~.graphviz_draw`,
+    :meth:`.PyGraph.to_dot`, and :meth:`.PyDiGraph.to_dot` to expose further
+    options around this.

src/dot_utils.rs

@@ -64,6 +64,8 @@ where
     Ok(())
 }
 
+static ATTRS_TO_ESCAPE: [&str; 2] = ["label", "tooltip"];
+
 /// Convert an attr map to an output string
 fn attr_map_to_string<'a>(
     py: Python,
@@ -85,15 +87,13 @@ fn attr_map_to_string<'a>(
     let attr_string = attrs
         .iter()
         .map(|(key, value)| {
-            let escaped_value = serde_json::to_string(value).map_err(|_err| {
-                pyo3::exceptions::PyValueError::new_err("could not escape character")
-            })?;
-            let escaped_value = &escaped_value.get(1..escaped_value.len() - 1).ok_or(
-                pyo3::exceptions::PyValueError::new_err("could not escape character"),
-            )?;
-            Ok(format!("{}=\"{}\"", key, escaped_value))
+            if ATTRS_TO_ESCAPE.contains(&key.as_str()) {
+                format!("{}=\"{}\"", key, value)
+            } else {
+                format!("{}={}", key, value)
+            }
         })
-        .collect::<PyResult<Vec<String>>>()?
+        .collect::<Vec<String>>()
         .join(", ");
     Ok(format!("[{}]", attr_string))
 }

tests/digraph/test_dot.py

@@ -43,9 +43,9 @@ def test_digraph_to_dot_to_file(self):
         )
         graph.add_edge(0, 1, dict(label="1", name="1"))
         expected = (
-            'digraph {\n0 [color="black", fillcolor="green", label="a", '
-            'style="filled"];\n1 [color="black", fillcolor="red", label="a", '
-            'style="filled"];\n0 -> 1 [label="1", name="1"];\n}\n'
+            'digraph {\n0 [color=black, fillcolor=green, label="a", '
+            'style=filled];\n1 [color=black, fillcolor=red, label="a", '
+            'style=filled];\n0 -> 1 [label="1", name=1];\n}\n'
         )
         res = graph.to_dot(lambda node: node, lambda edge: edge, filename=self.path)
         self.addCleanup(os.remove, self.path)

tests/graph/test_dot.py

@@ -43,9 +43,9 @@ def test_graph_to_dot(self):
         )
         graph.add_edge(0, 1, dict(label="1", name="1"))
         expected = (
-            'graph {\n0 [color="black", fillcolor="green", label="a", style="filled"'
-            '];\n1 [color="black", fillcolor="red", label="a", style="filled"];'
-            '\n0 -- 1 [label="1", name="1"];\n}\n'
+            'graph {\n0 [color=black, fillcolor=green, label="a", style=filled'
+            '];\n1 [color=black, fillcolor=red, label="a", style=filled];'
+            '\n0 -- 1 [label="1", name=1];\n}\n'
         )
         res = graph.to_dot(lambda node: node, lambda edge: edge)
         self.assertEqual(expected, res)
@@ -70,9 +70,9 @@ def test_digraph_to_dot(self):
         )
         graph.add_edge(0, 1, dict(label="1", name="1"))
         expected = (
-            'digraph {\n0 [color="black", fillcolor="green", label="a", '
-            'style="filled"];\n1 [color="black", fillcolor="red", label="a", '
-            'style="filled"];\n0 -> 1 [label="1", name="1"];\n}\n'
+            'digraph {\n0 [color=black, fillcolor=green, label="a", '
+            'style=filled];\n1 [color=black, fillcolor=red, label="a", '
+            'style=filled];\n0 -> 1 [label="1", name=1];\n}\n'
         )
         res = graph.to_dot(lambda node: node, lambda edge: edge)
         self.assertEqual(expected, res)
@@ -97,9 +97,9 @@ def test_graph_to_dot_to_file(self):
         )
         graph.add_edge(0, 1, dict(label="1", name="1"))
         expected = (
-            'graph {\n0 [color="black", fillcolor="green", label="a", '
-            'style="filled"];\n1 [color="black", fillcolor="red", label="a", '
-            'style="filled"];\n0 -- 1 [label="1", name="1"];\n}\n'
+            'graph {\n0 [color=black, fillcolor=green, label="a", '
+            'style=filled];\n1 [color=black, fillcolor=red, label="a", '
+            'style=filled];\n0 -- 1 [label="1", name=1];\n}\n'
         )
         res = graph.to_dot(lambda node: node, lambda edge: edge, filename=self.path)
         self.addCleanup(os.remove, self.path)

tests/visualization/test_graphviz.py

@@ -150,6 +150,55 @@ def test_filename(self):
         if not SAVE_IMAGES:
             self.addCleanup(os.remove, "test_graphviz_filename.svg")
 
+    def test_qiskit_style_visualization(self):
+        """This test is to test visualizations like qiskit performs which regressed in 0.15.0."""
+        graph = rustworkx.generators.cycle_graph(4)
+        colors = ["#422952", "#492d58", "#4f305c", "#5e3767"]
+        edge_colors = ["#4d2f5b", "#693d6f", "#995a88", "#382449"]
+        pos = [(0, 0), (0, 1), (1, 0), (1, 1)]
+        for node in graph.node_indices():
+            graph[node] = node
+
+        for edge in graph.edge_indices():
+            graph.update_edge_by_index(edge, edge)
+
+        def color_node(node):
+            out_dict = {
+                "label": str(node),
+                "color": f'"{colors[node]}"',
+                "pos": f'"{pos[node][0]}, {pos[node][1]}"',
+                "fontname": '"DejaVu Sans"',
+                "pin": "True",
+                "shape": "circle",
+                "style": "filled",
+                "fillcolor": f'"{colors[node]}"',
+                "fontcolor": "white",
+                "fontsize": "10",
+                "height": "0.322",
+                "fixedsize": "True",
+            }
+            return out_dict
+
+        def color_edge(edge):
+            out_dict = {
+                "color": f'"{edge_colors[edge]}"',
+                "fillcolor": f'"{edge_colors[edge]}"',
+                "penwidth": str(5),
+            }
+            return out_dict
+
+        graphviz_draw(
+            graph,
+            node_attr_fn=color_node,
+            edge_attr_fn=color_edge,
+            filename="test_qiskit_style_visualization.png",
+            image_type="png",
+            method="neato",
+        )
+        self.assertTrue(os.path.isfile("test_qiskit_style_visualization.png"))
+        if not SAVE_IMAGES:
+            self.addCleanup(os.remove, "test_qiskit_style_visualization.png")
+
     def test_escape_sequences(self):
         # Create a simple graph
         graph = rustworkx.generators.path_graph(2)