dag: mermaid: Use quotation marks to escape node name.

Fixes #7731

dvc/commands/dag.py

@@ -42,7 +42,7 @@ def _show_mermaid(G, markdown: bool = False):
         for node in nodes:
             total_nodes += 1
             node_id = f"node{total_nodes}"
-            graph += f"\n\t{node_id}[{node}]"
+            graph += f'\n\t{node_id}["{node}"]'
             node_ids[node] = node_id
         edges = sorted((str(a), str(b)) for b, a in pipeline.edges)
         for a, b in edges:

tests/unit/command/test_dag.py

@@ -165,12 +165,12 @@ def test_show_mermaid(repo):
         line.rstrip() for line in _show_mermaid(repo.index.graph).splitlines()
     ] == [
         "flowchart TD",
-        "\tnode1[stage: '1']",
-        "\tnode2[stage: '2']",
-        "\tnode3[stage: '3']",
-        "\tnode4[stage: '4']",
-        "\tnode5[stage: 'a.dvc']",
-        "\tnode6[stage: 'b.dvc']",
+        "\tnode1[\"stage: '1'\"]",
+        "\tnode2[\"stage: '2'\"]",
+        "\tnode3[\"stage: '3'\"]",
+        "\tnode4[\"stage: '4'\"]",
+        "\tnode5[\"stage: 'a.dvc'\"]",
+        "\tnode6[\"stage: 'b.dvc'\"]",
         "\tnode3-->node4",
         "\tnode5-->node1",
         "\tnode5-->node3",
@@ -190,12 +190,12 @@ def test_show_mermaid_markdown(repo, dvc, capsys, mocker):
     ] == [
         "```mermaid",
         "flowchart TD",
-        "\tnode1[stage: '1']",
-        "\tnode2[stage: '2']",
-        "\tnode3[stage: '3']",
-        "\tnode4[stage: '4']",
-        "\tnode5[stage: 'a.dvc']",
-        "\tnode6[stage: 'b.dvc']",
+        "\tnode1[\"stage: '1'\"]",
+        "\tnode2[\"stage: '2'\"]",
+        "\tnode3[\"stage: '3'\"]",
+        "\tnode4[\"stage: '4'\"]",
+        "\tnode5[\"stage: 'a.dvc'\"]",
+        "\tnode6[\"stage: 'b.dvc'\"]",
         "\tnode3-->node4",
         "\tnode5-->node1",
         "\tnode5-->node3",