feat(child-workflows): nested execution snapshots

[icecrasher321]

Summary

Child workflow previews in the logs should be based on their own execution snapshots.

Type of Change

• New feature

Testing

Tested manually

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 29, 2026 3:40am

[greptile-apps]

Greptile Overview

Greptile Summary

This PR enables child workflow previews in execution logs to use their own execution snapshots instead of the current live state. The implementation creates workflow snapshots during child workflow execution, stores snapshot IDs in trace spans, fetches them via the API, and uses them when drilling down in the UI.

Key changes:

• Snapshot creation during child workflow execution with deduplication
• Snapshot IDs propagated through execution flow, trace spans, and error handling
• API endpoint recursively collects and fetches child workflow snapshots
• UI components use snapshot state when viewing historical executions

Impact:
This ensures that historical execution logs show the exact workflow state that was executed, not the current state which may have changed since the execution occurred.

Confidence Score: 4/5

• This PR is safe to merge with minor considerations around database query performance
• The implementation is well-structured and follows the existing patterns in the codebase. The logic correctly handles both success and error cases, and the snapshot deduplication prevents unnecessary database bloat. One area to monitor is the batch query performance when fetching child snapshots, but the use of inArray should be efficient.
• Check apps/sim/app/api/logs/execution/[executionId]/route.ts for query performance with deeply nested workflows

Important Files Changed

Filename	Overview
apps/sim/executor/handlers/workflow/workflow-handler.ts	Added snapshot creation for child workflows and propagated snapshot IDs through execution flow
apps/sim/lib/logs/execution/trace-spans/trace-spans.ts	Extracted and attached childWorkflowSnapshotId and childWorkflowId from block outputs to trace spans
apps/sim/app/api/logs/execution/[executionId]/route.ts	Added logic to recursively collect child workflow snapshot IDs from trace spans and fetch them from database
apps/sim/app/workspace/[workspaceId]/w/components/preview/components/preview-editor/preview-editor.tsx	Added logic to prefer snapshot state over live state when drilling down into child workflows in execution mode

Sequence Diagram

sequenceDiagram
    participant WH as WorkflowHandler
    participant SS as SnapshotService
    participant EX as Executor
    participant BE as BlockExecutor
    participant DB as Database
    participant API as API Route
    participant UI as UI Components

    Note over WH,SS: Child Workflow Execution
    WH->>SS: createSnapshotWithDeduplication(workflowId, childWorkflowState)
    SS->>DB: Check for existing snapshot by hash
    alt Snapshot exists
        SS-->>WH: Return existing snapshot
    else New snapshot
        SS->>DB: Insert new snapshot
        SS-->>WH: Return new snapshot
    end
    Note over WH: Store childWorkflowSnapshotId
    
    WH->>EX: Execute child workflow
    EX->>BE: Execute blocks
    
    alt Success
        BE-->>WH: Execution result
        WH-->>WH: Map result with childWorkflowSnapshotId
    else Error
        BE-->>WH: ChildWorkflowError
        WH-->>WH: Propagate childWorkflowSnapshotId in error
    end
    
    Note over WH: Build trace spans with childWorkflowSnapshotId
    
    Note over DB,UI: Execution Logs & Viewing
    DB->>DB: Store execution log with trace spans
    
    UI->>API: GET /api/logs/execution/[executionId]
    API->>DB: Fetch execution log
    API->>API: Recursively collect childWorkflowSnapshotIds from trace spans
    API->>DB: Fetch child workflow snapshots (batch query)
    API-->>UI: Return execution data + childWorkflowSnapshots map
    
    UI->>UI: Pass childWorkflowSnapshots to Preview component
    UI->>UI: Use snapshot state when drilling down into child workflows

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[icecrasher321]

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