fix(executor): streaming response format

[Sg312]

Summary

Fixes response format streaming

Type of Change

• Bug fix

Testing

Manual

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	Preview	Comments	Updated (UTC)
docs	Skipped			Nov 13, 2025 11:13pm

[greptile-apps]

Greptile Overview

Greptile Summary

Changed streaming response format handling from mutation-based (Object.assign) to immutable object creation. When a responseFormat is defined, the executor now creates a new output object by spreading the parsed JSON content and explicitly preserving execution metadata fields (tokens, toolCalls, providerTiming, cost, model).

Key improvements:

• Replaces Object.assign(executionOutput, parsed) with immutable spread pattern
• Ensures execution metadata is preserved when response format is applied
• More predictable behavior by avoiding in-place mutation

Minor inconsistency:

• Non-responseFormat path (line 583) still uses direct mutation (executionOutput.content = fullContent), though this is less critical

Confidence Score: 4/5

• This PR is safe to merge with minimal risk - it fixes a specific bug in response format streaming
• The change correctly addresses the response format streaming issue by replacing mutation with immutable object creation. The fix preserves all necessary execution metadata fields. Minor style inconsistency exists in the non-responseFormat code path but doesn't impact functionality
• No files require special attention - the single file change is straightforward and properly scoped

Important Files Changed

File Analysis

Filename	Score	Overview
apps/sim/executor/execution/block-executor.ts	4/5	Fixed response format streaming by replacing Object.assign mutation with immutable object creation, but inconsistency remains with non-responseFormat path

Sequence Diagram

sequenceDiagram
    participant BH as BlockHandler
    participant BE as BlockExecutor
    participant CES as consumeExecutorStream
    participant Client as onStream Callback
    
    BH->>BE: execute() returns StreamingExecution
    Note over BE: { stream, execution }
    
    BE->>BE: handleStreamingExecution()
    BE->>BE: stream.tee()
    Note over BE: Split into clientStream<br/>& executorStream
    
    par Client Consumption
        BE->>Client: onStream(processedClientStream)
        Client-->>BE: consume stream
    and Executor Consumption
        BE->>CES: consumeExecutorStream(executorStream)
        loop Read chunks
            CES->>CES: decoder.decode(chunk)
            Note over CES: Accumulate fullContent
        end
        
        alt responseFormat defined
            CES->>CES: JSON.parse(fullContent)
            CES->>CES: Create new output object
            Note over CES: NEW: Immutable assignment<br/>preserves tokens, toolCalls,<br/>providerTiming, cost, model
            CES->>BE: streamingExec.execution.output = {...}
        else no responseFormat
            CES->>BE: executionOutput.content = fullContent
            Note over CES: Still uses mutation
        end
    end
    
    BE->>BE: normalizeOutput(execution.output)

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[greptile-apps]

Additional Comments (1)

1. apps/sim/executor/execution/block-executor.ts, line 583 (link)

   style: inconsistent mutation pattern - when responseFormat is defined, you create a new immutable object (lines 569-576), but here you're still mutating executionOutput.content directly

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