From d1846da0d29031192165c1ceefac142c010738a5 Mon Sep 17 00:00:00 2001
From: Tom Ratcliffe <tom.ratcliffe@grafana.com>
Date: Fri, 20 Dec 2024 16:13:32 +0000
Subject: [PATCH] Alerting: Skip non-expression queries in DAG creation
 (#98315)

---
 .../components/rule-editor/dag.test.ts        | 48 ++++++++++++++++---
 .../unified/components/rule-editor/dag.ts     |  5 +-
 2 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/public/app/features/alerting/unified/components/rule-editor/dag.test.ts b/public/app/features/alerting/unified/components/rule-editor/dag.test.ts
index eecc88977ff..513d41abffe 100644
--- a/public/app/features/alerting/unified/components/rule-editor/dag.test.ts
+++ b/public/app/features/alerting/unified/components/rule-editor/dag.test.ts
@@ -35,30 +35,64 @@ describe('working with dag', () => {
           type: 'math',
         },
       },
+      {
+        refId: 'D',
+        model: {
+          refId: 'D',
+          expression: 'B',
+          type: 'threshold',
+        },
+      },
     ] as AlertQuery[];
 
     const dag = _createDagFromQueries(queries);
 
-    expect(Object.keys(dag.nodes)).toHaveLength(3);
+    expect(Object.keys(dag.nodes)).toHaveLength(4);
 
     expect(() => {
       dag.getNode('A');
       dag.getNode('B');
       dag.getNode('C');
+      dag.getNode('D');
     }).not.toThrow();
 
     expect(dag.getNode('A').inputEdges).toHaveLength(0);
-    expect(dag.getNode('A').outputEdges).toHaveLength(1);
-    expect(dag.getNode('A').outputEdges[0].outputNode).toHaveProperty('name', 'B');
+    expect(dag.getNode('A').outputEdges).toHaveLength(0);
 
-    expect(dag.getNode('B').inputEdges).toHaveLength(1);
-    expect(dag.getNode('B').outputEdges).toHaveLength(1);
-    expect(dag.getNode('B').inputEdges[0].inputNode).toHaveProperty('name', 'A');
+    expect(dag.getNode('B').inputEdges).toHaveLength(0);
+    expect(dag.getNode('B').outputEdges).toHaveLength(2);
     expect(dag.getNode('B').outputEdges[0].outputNode).toHaveProperty('name', 'C');
+    expect(dag.getNode('B').outputEdges[1].outputNode).toHaveProperty('name', 'D');
 
     expect(dag.getNode('C').inputEdges).toHaveLength(1);
-    expect(dag.getNode('C').outputEdges).toHaveLength(0);
     expect(dag.getNode('C').inputEdges[0].inputNode).toHaveProperty('name', 'B');
+    expect(dag.getNode('C').outputEdges).toHaveLength(0);
+
+    expect(dag.getNode('D').inputEdges).toHaveLength(1);
+    expect(dag.getNode('D').inputEdges[0].inputNode).toHaveProperty('name', 'B');
+    expect(dag.getNode('D').outputEdges).toHaveLength(0);
+  });
+
+  test('data queries cannot have references', () => {
+    const queries = [
+      {
+        refId: 'A',
+        model: {
+          refId: 'A',
+          expression: 'vector(1)',
+        },
+      },
+    ] as AlertQuery[];
+
+    expect(() => _createDagFromQueries(queries)).not.toThrow();
+
+    const dag = _createDagFromQueries(queries);
+
+    expect(Object.keys(dag.nodes)).toHaveLength(1);
+
+    expect(() => {
+      dag.getNode('A');
+    }).not.toThrow();
   });
 });
 
diff --git a/public/app/features/alerting/unified/components/rule-editor/dag.ts b/public/app/features/alerting/unified/components/rule-editor/dag.ts
index cd4583fe6e2..4900ea70025 100644
--- a/public/app/features/alerting/unified/components/rule-editor/dag.ts
+++ b/public/app/features/alerting/unified/components/rule-editor/dag.ts
@@ -24,8 +24,11 @@ export function _createDagFromQueries(queries: AlertQuery[]): Graph {
   graph.createNodes(nodes);
 
   queries.forEach((query) => {
+    if (!isExpressionQuery(query.model)) {
+      return;
+    }
     const source = query.refId;
-    const isMathExpression = isExpressionQuery(query.model) && query.model.type === 'math';
+    const isMathExpression = query.model.type === 'math';
 
     // some expressions have multiple targets (like the math expression)
     const targets = isMathExpression