fix: add validation for edge expressions

CHANGELOG.md

@@ -17,6 +17,9 @@ and this project adheres to
 
 ### Added
 
+- Add validation for edge expressions
+  [#3704](https://github.com/OpenFn/lightning/issues/3704)
+
 ### Changed
 
 - Default failure notifications for project users are now disabled to minimize

assets/js/collaborative-editor/components/inspector/EdgeForm.tsx

@@ -1,5 +1,5 @@
 import { useStore } from '@tanstack/react-form';
-import { useMemo } from 'react';
+import { useEffect, useMemo } from 'react';
 
 import {
   useWorkflowActions,
@@ -30,7 +30,10 @@ export function EdgeForm({ edge }: EdgeFormProps) {
   // Initialize form
   const form = useAppForm(
     {
-      defaultValues: edge,
+      defaultValues: {
+        ...edge,
+        condition_expression: edge.condition_expression || '',
+      },
       listeners: {
         onChange: ({ formApi }) => {
           if (edge.id) {
@@ -97,6 +100,13 @@ export function EdgeForm({ edge }: EdgeFormProps) {
       conditionExpression
     );
 
+  // Trigger validation when switching to js_expression
+  useEffect(() => {
+    if (conditionType === 'js_expression') {
+      form.validateField('condition_expression', 'change');
+    }
+  }, [conditionType, form]);
+
   return (
     <div className="px-6 py-6 space-y-4">
       {/* Label Field */}

assets/js/collaborative-editor/types/edge.ts

@@ -1,12 +1,12 @@
-import { z } from "zod";
+import { z } from 'zod';
 
-import { uuidSchema } from "./common";
+import { uuidSchema } from './common';
 
 export const EdgeConditionType = z.enum([
-  "on_job_success",
-  "on_job_failure",
-  "always",
-  "js_expression",
+  'on_job_success',
+  'on_job_failure',
+  'always',
+  'js_expression',
 ]);
 
 export const EdgeSchema = z
@@ -23,15 +23,15 @@ export const EdgeSchema = z
     target_job_id: uuidSchema,
 
     // Condition configuration
-    condition_type: EdgeConditionType.default("on_job_success"),
+    condition_type: EdgeConditionType.default('on_job_success'),
     condition_expression: z
       .string()
-      .max(255, "should be at most 255 character(s)")
-      .nullable()
-      .optional(),
+      .trim()
+      .min(1, "This field can't be blank")
+      .max(255, 'should be at most 255 character(s)'),
     condition_label: z
       .string()
-      .max(255, "should be at most 255 character(s)")
+      .max(255, 'should be at most 255 character(s)')
       .nullable()
       .optional(),
 
@@ -48,14 +48,14 @@ export const EdgeSchema = z
   .refine(
     data => {
       // Require expression when type is js_expression
-      if (data.condition_type === "js_expression") {
-        return !!data.condition_expression;
+      if (data.condition_type === 'js_expression') {
+        return !!data.condition_expression.trim();
       }
       return true;
     },
     {
-      message: "can't be blank",
-      path: ["condition_expression"],
+      message: "This field can't be blank",
+      path: ['condition_expression'],
     }
   );