improvement(response-copilot): prefer builder mode + fix builder/editor mode conversions

[icecrasher321]

Summary

• Moving between builder and editor mode correctly converts
• Copilot best practice is to use builder mode since JSON generation is weaker.

Type of Change

• Bug fix

Testing

Tested manually + trained copilot on conversion op

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)

[vercel]

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1 Skipped Deployment

Project	Deployment	Preview	Comments	Updated (UTC)
docs	Skipped			Oct 16, 2025 2:07am

[icecrasher321]

this prevents nuking diff store if copilot outputs invalid fields i.e. not an array

[greptile-apps]

Greptile Overview

Summary

Implements bidirectional conversion between builder and editor modes for the Response block, using refs to avoid stale closure issues and moving conversion logic to a useEffect.

Key changes:

• Added previousModeRef to track mode changes and trigger conversions only when mode actually changes
• Used refs (builderDataRef, dataRef) to access latest values in useEffect without stale closures
• Moved conversion logic from handleSelect to dedicated useEffect for better separation
• Updated best practices to prefer builder mode since JSON generation is weaker
• Added defensive type guard in input-format.tsx to prevent crashes when value is not an array

Critical issue found:

• The regex pattern in normalizeVariableReferences incorrectly captures the character before variable references, producing malformed JSON that will cause JSON.parse to fail when converting from editor to builder mode

Confidence Score: 1/5

• This PR has a critical regex bug that will break editor-to-builder conversion
• The normalizeVariableReferences regex pattern /([^"]<[^>]+>)/g captures one character before the variable reference (e.g., : <var> becomes ": <var>" resulting in "": <var>"), producing invalid JSON that will cause runtime errors when users switch from editor to builder mode
• Pay close attention to dropdown.tsx - the regex bug on line 120 must be fixed before merge

Important Files Changed

File Analysis

Filename	Score	Overview
apps/sim/blocks/blocks/response.ts	5/5	Updated best practices to prefer builder mode over editor mode - simple documentation change
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/workflow-block/components/sub-block/components/starter/input-format.tsx	5/5	Added type guard for array values and improved placeholder text - safe defensive changes
apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/workflow-block/components/sub-block/components/dropdown.tsx	1/5	Implements bidirectional mode conversion with refs to avoid stale closures, but regex bug will break JSON-to-builder conversion

Sequence Diagram

sequenceDiagram
participant User
participant Dropdown
participant Store
participant ResponseBlockHandler
User->>Dropdown: Select mode (structured/json)
Dropdown->>Dropdown: handleSelect(selectedValue)
Dropdown->>Store: setStoreValue(selectedValue)
Note over Dropdown: useEffect triggered by storeValue change
Dropdown->>Dropdown: Check if subBlockId === 'dataMode'
Dropdown->>Dropdown: Compare previousMode vs currentMode
alt Builder → Editor (structured → json)
Dropdown->>Dropdown: Get builderDataRef.current
Dropdown->>ResponseBlockHandler: convertBuilderDataToJsonString(builderData)
ResponseBlockHandler-->>Dropdown: jsonString
Dropdown->>Store: setData(jsonString)
else Editor → Builder (json → structured)
Dropdown->>Dropdown: Get dataRef.current
Dropdown->>Dropdown: normalizeVariableReferences(jsonString)
Note right of Dropdown: ⚠️ Regex bug: creates invalid JSON
Dropdown->>Dropdown: convertJsonToBuilderData(jsonString)
Dropdown-->>Dropdown: builderArray
Dropdown->>Store: setBuilderData(builderArray)
end
Dropdown->>Dropdown: Update previousModeRef.current

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_{3 files reviewed, 1 comment}

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[greptile-apps]

logic: regex pattern incorrectly captures the character before <, causing malformed JSON (e.g., : <var> becomes ": <var>" → "": <var>")

Suggested change

	constnormalizeVariableReferences=(jsonString: string): string=>{
	// Replace unquoted variable references with quoted ones
	// Pattern: <variable.name> -> "<variable.name>"
	returnjsonString.replace(/([^"]<[^>]+>)/g,'"$1"')
	}
	constnormalizeVariableReferences=(jsonString: string): string=>{
	// Replace unquoted variable references with quoted ones
	// Pattern: <variable.name> -> "<variable.name>"
	returnjsonString.replace(/(?<!")(<[^>]+>)(?!")/g,'"$1"')
	}

Prompt To Fix With AI

This is a comment left during a code review.
Path: apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/workflow-block/components/sub-block/components/dropdown.tsx
Line: 117:121
Comment:
**logic:** regex pattern incorrectly captures the character before `<`, causing malformed JSON (e.g., `: <var>` becomes `": <var>"` → `"": <var>"`)
```suggestion const normalizeVariableReferences = (jsonString: string): string => { // Replace unquoted variable references with quoted ones // Pattern: <variable.name> -> "<variable.name>" return jsonString.replace(/(?<!")(<[^>]+>)(?!")/g, '"$1"') }```
How can I resolve this? If you propose a fix, please make it concise.