fix: node connect self (#3194)

web/app/components/workflow/hooks/use-workflow.ts

@@ -160,8 +160,10 @@ export const useWorkflow = () => {
 
         if (incomers.length) {
           incomers.forEach((node) => {
-            callback(node)
-            traverse(node, callback)
+            if (!list.find(n => node.id === n.id)) {
+              callback(node)
+              traverse(node, callback)
+            }
           })
         }
       }
@@ -272,7 +274,10 @@ export const useWorkflow = () => {
   }, [isVarUsedInNodes])
 
   const isValidConnection = useCallback(({ source, target }: Connection) => {
-    const { getNodes } = store.getState()
+    const {
+      edges,
+      getNodes,
+    } = store.getState()
     const nodes = getNodes()
     const sourceNode: Node = nodes.find(node => node.id === source)!
     const targetNode: Node = nodes.find(node => node.id === target)!
@@ -287,7 +292,21 @@ export const useWorkflow = () => {
         return false
     }
 
-    return true
+    const hasCycle = (node: Node, visited = new Set()) => {
+      if (visited.has(node.id))
+        return false
+
+      visited.add(node.id)
+
+      for (const outgoer of getOutgoers(node, nodes, edges)) {
+        if (outgoer.id === source)
+          return true
+        if (hasCycle(outgoer, visited))
+          return true
+      }
+    }
+
+    return !hasCycle(targetNode)
   }, [store, nodesExtraData])
 
   const formatTimeFromNow = useCallback((time: number) => {