From f86fc1a1795cc5dd07012589a1f8fd3c2a605ff4 Mon Sep 17 00:00:00 2001
From: medchedli <medchedliby@gmail.com>
Date: Tue, 3 Jun 2025 11:55:51 +0100
Subject: [PATCH 1/2] fix: prevent duplicate links in nextBlocks when updating
 block

---
 .../components/visual-editor/v2/Diagrams.tsx  | 46 ++++++++++---------
 1 file changed, 25 insertions(+), 21 deletions(-)

diff --git a/frontend/src/components/visual-editor/v2/Diagrams.tsx b/frontend/src/components/visual-editor/v2/Diagrams.tsx
index d9060e41..b530efe0 100644
--- a/frontend/src/components/visual-editor/v2/Diagrams.tsx
+++ b/frontend/src/components/visual-editor/v2/Diagrams.tsx
@@ -291,30 +291,34 @@ const Diagrams = () => {
           entity.getSourcePort().getOptions()?.label ===
           BlockPorts.nextBlocksOutPort
         ) {
-          const nextBlocks = [
-            ...(previousData?.nextBlocks || []),
-            ...(targetId ? [targetId] : []),
-          ];
+          // Only add the link if targetId exists, skip if targetId is null
+          if (!targetId) {
+            return;
+          }
+          // Only add the link if targetId doesn't already exist in nextBlocks
+          if (!previousData?.nextBlocks?.includes(targetId)) {
+            const nextBlocks = [...(previousData?.nextBlocks || []), targetId];
 
-          updateBlock(
-            {
-              id: sourceId,
-              params: {
-                nextBlocks,
+            updateBlock(
+              {
+                id: sourceId,
+                params: {
+                  nextBlocks,
+                },
               },
-            },
-            {
-              onSuccess(data) {
-                if (data.id)
-                  updateCachedBlock({
-                    id: targetId,
-                    payload: {
-                      previousBlocks: [data.id as any],
-                    },
-                  });
+              {
+                onSuccess(data) {
+                  if (data.id)
+                    updateCachedBlock({
+                      id: targetId,
+                      payload: {
+                        previousBlocks: [data.id as any],
+                      },
+                    });
+                },
               },
-            },
-          );
+            );
+          }
         } else if (
           // @ts-expect-error undefined attr
           entity.getSourcePort().getOptions().label ===

From de6d30e854701f3832fc77f1fd487fd57749e5d4 Mon Sep 17 00:00:00 2001
From: medchedli <medchedliby@gmail.com>
Date: Wed, 4 Jun 2025 18:43:09 +0100
Subject: [PATCH 2/2] fix: apply feedback

---
 .../components/visual-editor/v2/Diagrams.tsx  | 61 +++++++++++--------
 1 file changed, 34 insertions(+), 27 deletions(-)

diff --git a/frontend/src/components/visual-editor/v2/Diagrams.tsx b/frontend/src/components/visual-editor/v2/Diagrams.tsx
index b530efe0..f6708e09 100644
--- a/frontend/src/components/visual-editor/v2/Diagrams.tsx
+++ b/frontend/src/components/visual-editor/v2/Diagrams.tsx
@@ -264,6 +264,19 @@ const Diagrams = () => {
           return;
         }
 
+        const sourceId = entity.getSourcePort().getParent().getOptions()
+          .id as string;
+        const targetId = entity.getTargetPort().getParent().getOptions()
+          .id as string;
+        const previousData = getBlockFromCache(sourceId!);
+
+        // Only add the link if targetId doesn't already exist in nextBlocks
+        if (previousData?.nextBlocks?.includes(targetId)) {
+          model.removeLink(link);
+
+          return;
+        }
+
         link.setLocked(true);
         link.registerListener({
           selectionChanged(event: any) {
@@ -280,12 +293,6 @@ const Diagrams = () => {
           }
         });
 
-        const sourceId = entity.getSourcePort().getParent().getOptions()
-          .id as string;
-        const targetId = entity.getTargetPort().getParent().getOptions()
-          .id as string;
-        const previousData = getBlockFromCache(sourceId!);
-
         if (
           // @ts-expect-error undefined attr
           entity.getSourcePort().getOptions()?.label ===
@@ -295,30 +302,30 @@ const Diagrams = () => {
           if (!targetId) {
             return;
           }
-          // Only add the link if targetId doesn't already exist in nextBlocks
-          if (!previousData?.nextBlocks?.includes(targetId)) {
-            const nextBlocks = [...(previousData?.nextBlocks || []), targetId];
+          const nextBlocks = [
+            ...(previousData?.nextBlocks || []),
+            ...(targetId ? [targetId] : []),
+          ];
 
-            updateBlock(
-              {
-                id: sourceId,
-                params: {
-                  nextBlocks,
-                },
+          updateBlock(
+            {
+              id: sourceId,
+              params: {
+                nextBlocks,
               },
-              {
-                onSuccess(data) {
-                  if (data.id)
-                    updateCachedBlock({
-                      id: targetId,
-                      payload: {
-                        previousBlocks: [data.id as any],
-                      },
-                    });
-                },
+            },
+            {
+              onSuccess(data) {
+                if (data.id)
+                  updateCachedBlock({
+                    id: targetId,
+                    payload: {
+                      previousBlocks: [data.id as any],
+                    },
+                  });
               },
-            );
-          }
+            },
+          );
         } else if (
           // @ts-expect-error undefined attr
           entity.getSourcePort().getOptions().label ===