fix(comparison): add condition to prevent duplicate identical edges

[waleedlatif1]

Summary

• add condition to prevent duplicate identical edges between the same source port and target ports

Type of Change

• Bug fix

Testing

Tested manaully

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
docs	Skipped		Jan 14, 2026 0:35am

[greptile-apps]

Greptile Summary

This PR restores duplicate edge prevention at the store level, implementing a more precise check that validates all four connection fields (source, sourceHandle, target, targetHandle) instead of just source and target nodes. This addresses the senior developer's previous feedback about programmatic edge additions potentially creating duplicates.

Key Changes:

• Enhanced batchAddEdges in store.ts to check for identical connections by comparing source port, source handle, target port, and target handle
• Maintained the connectionCompletedRef pattern in workflow.tsx to distinguish between handle-to-handle and handle-to-body drag operations
• The two-layer approach provides defense in depth: UI-level prevention via ref tracking and store-level validation for programmatic calls

Why This Approach:
The developer noted "so many codepaths converge at this point" - batchAddEdges is called from multiple sources (user interactions, collaborative updates, imports, etc.), so having duplicate prevention at the store level ensures consistency regardless of the calling context.

Confidence Score: 5/5

• This PR is safe to merge with no identified risks
• The implementation correctly addresses the previous reviewer's concern by adding comprehensive duplicate detection that checks all four connection fields. The logic properly handles both existing edges and edges being added in the current batch. The connectionCompletedRef pattern in the UI layer works correctly with the store-level validation to prevent duplicates from all code paths.
• No files require special attention

Important Files Changed

Filename	Overview
apps/sim/stores/workflows/workflow/store.ts	Added precise duplicate edge detection checking all four connection fields (source, sourceHandle, target, targetHandle) instead of just source and target
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/workflow.tsx	Uses connectionCompletedRef pattern to prevent duplicate connections when dropping edges, avoiding the need for store-level duplicate checks in onConnectEnd

Sequence Diagram

sequenceDiagram
    participant User
    participant onConnectStart
    participant onConnect
    participant onConnectEnd
    participant batchAddEdges
    
    User->>onConnectStart: Start dragging connection
    activate onConnectStart
    onConnectStart->>onConnectStart: Set connectionCompletedRef = false
    onConnectStart->>onConnectStart: Store source node/handle
    deactivate onConnectStart
    
    alt Handle-to-handle connection
        User->>onConnect: Drop on target handle
        activate onConnect
        onConnect->>onConnect: Validate connection
        onConnect->>batchAddEdges: Add edge
        activate batchAddEdges
        batchAddEdges->>batchAddEdges: Check if edge ID exists
        batchAddEdges->>batchAddEdges: Check for self-reference
        batchAddEdges->>batchAddEdges: Check if identical connection exists<br/>(source, sourceHandle, target, targetHandle)
        batchAddEdges->>batchAddEdges: Check for cycles
        batchAddEdges->>batchAddEdges: Add edge to store
        deactivate batchAddEdges
        onConnect->>onConnect: Set connectionCompletedRef = true
        deactivate onConnect
        User->>onConnectEnd: Connection drag ends
        activate onConnectEnd
        onConnectEnd->>onConnectEnd: Check connectionCompletedRef = true
        onConnectEnd->>onConnectEnd: Skip (already handled)
        deactivate onConnectEnd
    else Handle-to-body connection
        User->>onConnectEnd: Drop on block body
        activate onConnectEnd
        onConnectEnd->>onConnectEnd: Check connectionCompletedRef = false
        onConnectEnd->>onConnectEnd: Find target node at cursor
        onConnectEnd->>onConnect: Create connection to 'target' handle
        activate onConnect
        onConnect->>batchAddEdges: Add edge
        activate batchAddEdges
        batchAddEdges->>batchAddEdges: Check duplicate (all 4 fields)
        batchAddEdges->>batchAddEdges: Add edge to store
        deactivate batchAddEdges
        onConnect->>onConnect: Set connectionCompletedRef = true
        deactivate onConnect
        deactivate onConnectEnd
    end

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[greptile-apps]

Additional Comments (1)

1. apps/sim/stores/workflows/workflow/store.ts, line 300-311 (link)

   logic: Check that test still passes - it expects calling batchAddEdges twice with different IDs but same source/target creates only one edge. With duplicate check removed, both edges will be added.

_{2 files reviewed, 2 comments}

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[waleedlatif1]

@greptile