fortify-schema/src/core/private/note/CONDITIONAL_VALIDATION_FIXES.md

A modern TypeScript validation library designed around familiar interface syntax and powerful conditional validation. Experience schema validation that feels natural to TypeScript developers while unlocking advanced runtime validation capabilities.

## 🐛 **Bug Found and Fixed**

### **Original Issue**
The conditional validation system was not properly applying constraint validation. Test data that should have failed validation was passing:

```typescript
const invalidData = {
  accountType: "free",
  maxProjects: 59, // Should fail (max 3 for free accounts)
  storageLimit: 60, // Should fail (max 50 for free accounts)
};

// This was incorrectly returning success: true
const result = schema.safeParse(invalidData);
```

### **Root Cause**
In `InterfaceSchema.ts`, the `validateStringFieldType` method was calling `this.validateBasicType(elementType, value)` where `elementType` was the parsed type without constraints (e.g., `"int"`) instead of the original field type with constraints (e.g., `"int(1,3)"`).

**File**: `src/core/schema/mode/interfaces/InterfaceSchema.ts`  
**Line**: 608  
**Problem**: `return this.validateBasicType(elementType, value);`  
**Fix**: `return this.validateBasicType(fieldType, value);`

### **Impact**
This bug affected ALL conditional validation that used constraint syntax, causing validation to pass when it should fail.

## 🔧 **Additional Bug Fixed**

### **Method Call Arguments Bug**
The `.in()` method was not working correctly because comma-separated arguments like `admin,manager` were being parsed as a single string `"admin,manager"` instead of an array `["admin", "manager"]`.

**File**: `src/core/schema/mode/interfaces/conditional/evaluator/ConditionalEvaluator.ts`  
**Solution**: Added `expandCommaSeparatedArgs()` method to properly split comma-separated values.

```typescript
private expandCommaSeparatedArgs(args: any[]): any[] {
  const expandedArgs: any[] = [];
  
  for (const arg of args) {
    if (typeof arg === "string" && arg.includes(",")) {
      const splitValues = arg.split(",").map(v => v.trim());
      expandedArgs.push(...splitValues);
    } else {
      expandedArgs.push(arg);
    }
  }
  
  return expandedArgs;
}
```

## ✅ **Features Now Working Correctly**

### **1. Constraint Syntax in Conditionals** ✅
```typescript
const schema = Interface({
  accountType: "free|premium",
  maxProjects: "when accountType=free *? int(1,3) : int(1,100)",
  storageLimit: "when accountType=premium *? int(100,) : int(10,50)",
  nameLength: "when role=admin *? string(5,50) : string(3,20)",
  discount: "when age>=65 *? number(0.1,0.3) : number(0,0.1)",
});
```

### **2. Method Calls** ✅
```typescript
const schema = Interface({
  role: "admin|manager|user|guest",
  elevatedAccess: "when role.in(admin,manager) *? =granted : =denied",
  notifications: "when email.exists *? =email : =none",
  premiumFeatures: "when tags.contains(premium) *? =enabled : =disabled",
});
```

### **3. Logical Operators** ✅
```typescript
const schema = Interface({
  fullAccess: "when role=admin && age>=18 *? =granted : =denied",
  managerAccess: "when role=admin || role=manager *? =granted : =denied",
  specialFeatures: "when role.in(admin,manager) || age>=65 *? =enabled : =disabled",
});
```

### **4. Nested Conditionals** ✅
```typescript
const schema = Interface({
  access: "when status=active *? when role=admin *? =full : =limited : =none",
  features: "when status=active *? when role=admin *? when level>=5 *? =all : =admin : =user : =none",
});
```

### **5. All Comparison Operators** ✅
- `=` (equality)
- `!=` (inequality)
- `>=`, `>`, `<=`, `<` (numeric comparisons)

## 📝 **Documentation Updated**

Updated `docs/CONDITIONAL_VALIDATION_GUIDE.md` to reflect that constraint syntax is now fully supported in conditionals, replacing the previous "Not Supported" section with comprehensive examples.

## 🧪 **Tests Added**

Created comprehensive regression test suite in `src/core/tests/conditional-validation-regression.test.ts` to ensure these features continue working correctly.

## 🎯 **Verification**

All features verified with comprehensive test suite:
- ✅ Constraint syntax validation
- ✅ Method calls (`.in()`, `.exists`, `.contains()`)
- ✅ Logical operators (`&&`, `||`)
- ✅ Nested conditionals
- ✅ All comparison operators
- ✅ Proper error messages for invalid data

## 📊 **Before vs After**

### **Before Fix**
```typescript
const result = schema.safeParse({
  accountType: "free",
  maxProjects: 59, // Should fail but didn't
  storageLimit: 60, // Should fail but didn't
});
// Result: { success: true, data: {...} } ❌ WRONG
```

### **After Fix**
```typescript
const result = schema.safeParse({
  accountType: "free",
  maxProjects: 59, // Correctly fails
  storageLimit: 60, // Correctly fails
});
// Result: { 
//   success: false, 
//   errors: [
//     "maxProjects: Integer must be at most 3",
//     "storageLimit: Integer must be at most 50"
//   ]
// } ✅ CORRECT
```

## 🚀 **Impact**

This fix significantly improves the conditional validation system, making it production-ready for complex business logic validation scenarios. The system now properly enforces all constraints in conditional expressions, preventing data integrity issues.