fix(codegen): function prologue resolution edge cases

apps/sim/app/api/function/execute/route.ts

@@ -387,7 +387,12 @@ function resolveWorkflowVariables(
       if (type === 'number') {
         variableValue = Number(variableValue)
       } else if (type === 'boolean') {
-        variableValue = variableValue === 'true' || variableValue === true
+        if (typeof variableValue === 'boolean') {
+          // Already a boolean, keep as-is
+        } else {
+          const normalized = String(variableValue).toLowerCase().trim()
+          variableValue = normalized === 'true' || normalized === '1'
+        }
       } else if (type === 'json' && typeof variableValue === 'string') {
         try {
           variableValue = JSON.parse(variableValue)
@@ -689,6 +694,10 @@ export async function POST(req: NextRequest) {
         for (const [k, v] of Object.entries(contextVariables)) {
           if (v === undefined) {
             prologue += `const ${k} = undefined;\n`
+          } else if (v === null) {
+            prologue += `const ${k} = null;\n`
+          } else if (typeof v === 'boolean' || typeof v === 'number') {
+            prologue += `const ${k} = ${v};\n`
           } else {
             prologue += `const ${k} = JSON.parse(${JSON.stringify(JSON.stringify(v))});\n`
           }
@@ -764,6 +773,12 @@ export async function POST(req: NextRequest) {
       for (const [k, v] of Object.entries(contextVariables)) {
         if (v === undefined) {
           prologue += `${k} = None\n`
+        } else if (v === null) {
+          prologue += `${k} = None\n`
+        } else if (typeof v === 'boolean') {
+          prologue += `${k} = ${v ? 'True' : 'False'}\n`
+        } else if (typeof v === 'number') {
+          prologue += `${k} = ${v}\n`
         } else {
           prologue += `${k} = json.loads(${JSON.stringify(JSON.stringify(v))})\n`
         }

apps/sim/executor/variables/resolver.ts

@@ -157,7 +157,14 @@ export class VariableResolver {
 
     let replacementError: Error | null = null
 
-    // Use generic utility for smart variable reference replacement
+    const blockType = block?.metadata?.id
+    const language =
+      blockType === BlockType.FUNCTION
+        ? ((block?.config?.params as Record<string, unknown> | undefined)?.language as
+            | string
+            | undefined)
+        : undefined
+
     let result = replaceValidReferences(template, (match) => {
       if (replacementError) return match
 
@@ -167,14 +174,18 @@ export class VariableResolver {
           return match
         }
 
-        const blockType = block?.metadata?.id
         const isInTemplateLiteral =
           blockType === BlockType.FUNCTION &&
           template.includes('${') &&
           template.includes('}') &&
           template.includes('`')
 
-        return this.blockResolver.formatValueForBlock(resolved, blockType, isInTemplateLiteral)
+        return this.blockResolver.formatValueForBlock(
+          resolved,
+          blockType,
+          isInTemplateLiteral,
+          language
+        )
       } catch (error) {
         replacementError = error instanceof Error ? error : new Error(String(error))
         return match

apps/sim/executor/variables/resolvers/block.ts

@@ -162,14 +162,15 @@ export class BlockResolver implements Resolver {
   public formatValueForBlock(
     value: any,
     blockType: string | undefined,
-    isInTemplateLiteral = false
+    isInTemplateLiteral = false,
+    language?: string
   ): string {
     if (blockType === 'condition') {
       return this.stringifyForCondition(value)
     }
 
     if (blockType === 'function') {
-      return this.formatValueForCodeContext(value, isInTemplateLiteral)
+      return this.formatValueForCodeContext(value, isInTemplateLiteral, language)
     }
 
     if (blockType === 'response') {
@@ -210,7 +211,13 @@ export class BlockResolver implements Resolver {
     return String(value)
   }
 
-  private formatValueForCodeContext(value: any, isInTemplateLiteral: boolean): string {
+  private formatValueForCodeContext(
+    value: any,
+    isInTemplateLiteral: boolean,
+    language?: string
+  ): string {
+    const isPython = language === 'python'
+
     if (isInTemplateLiteral) {
       if (typeof value === 'string') {
         return value
@@ -218,6 +225,15 @@ export class BlockResolver implements Resolver {
       if (typeof value === 'object' && value !== null) {
         return JSON.stringify(value)
       }
+      if (typeof value === 'boolean') {
+        return isPython ? (value ? 'True' : 'False') : String(value)
+      }
+      if (value === undefined) {
+        return isPython ? 'None' : 'undefined'
+      }
+      if (value === null) {
+        return isPython ? 'None' : 'null'
+      }
       return String(value)
     }
 
@@ -228,10 +244,13 @@ export class BlockResolver implements Resolver {
       return JSON.stringify(value)
     }
     if (value === undefined) {
-      return 'undefined'
+      return isPython ? 'None' : 'undefined'
     }
     if (value === null) {
-      return 'null'
+      return isPython ? 'None' : 'null'
+    }
+    if (typeof value === 'boolean') {
+      return isPython ? (value ? 'True' : 'False') : String(value)
     }
     return String(value)
   }

apps/sim/lib/execution/isolated-vm-worker.cjs

@@ -132,6 +132,8 @@ async function executeCode(request) {
     for (const [key, value] of Object.entries(contextVariables)) {
       if (value === undefined) {
         await jail.set(key, undefined)
+      } else if (value === null) {
+        await jail.set(key, null)
       } else {
         await jail.set(key, new ivm.ExternalCopy(value).copyInto())
       }