fix(payments): improve price validation and handling in product dialogs

- Added validation to ensure at least one price is provided when saving a product.
- Enhanced error handling to clear price-related errors when prices are updated.
- Updated price validation schema to allow for null values.
- Removed unnecessary price reset logic in the product prices section.

These changes aim to improve user experience by enforcing price requirements and providing clearer feedback in the product dialog.

Author: mantrakp04

apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/switch/route.ts

@@ -116,7 +116,8 @@ export const POST = createSmartRouteHandler({
         Object.values(subMap).filter(s => isActiveSubscription(s)).map(s => s.productId ?? "__null__")
       );
       const hasOtpInProductLine = Object.entries(ownedProducts).some(
-        ([productId, p]) => p.productLineId === fromProduct.productLineId
+        ([productId, p]) => productId !== body.from_product_id
+          && p.productLineId === fromProduct.productLineId
           && p.quantity > 0
           && !activeSubProductIds.has(productId)
       );

apps/backend/src/app/api/latest/payments/purchases/validate-code/route.ts

@@ -80,7 +80,8 @@ export const POST = createSmartRouteHandler({
     const productLineId = Object.keys(productLines).find((g) => product.productLineId === g);
     let conflictingProductLineProducts: { product_id: string, display_name: string }[] = [];
     if (productLineId) {
-      const isSubscribable = Object.values(product.prices).some((p: any) => p && p.interval);
+      const productPrices = product.prices;
+      const isSubscribable = productPrices !== "include-by-default" && Object.values(productPrices).some((p) => p != null && p.interval != null);
       if (isSubscribable) {
         const addOnBaseProductIds = product.isAddOnTo ? new Set(Object.keys(product.isAddOnTo)) : new Set<string>();
         conflictingProductLineProducts = Object.entries(ownedProducts)

apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/payments/products/[productId]/page-client.tsx

@@ -864,7 +864,6 @@ function ProductPricesSection({ productId, prices, onPricesChange, inline = fals
   const hasNoPrices = priceEntries.length === 0;
 
   const handleMakePaid = () => {
-    onPricesChange({});
     openAddDialog();
   };
 

apps/dashboard/src/app/(main)/(protected)/projects/[projectId]/payments/products/product-dialog.tsx

@@ -161,6 +161,11 @@ export function ProductDialog({
   };
 
   const handleSave = async () => {
+    if (Object.keys(prices).length === 0) {
+      setErrors({ prices: "At least one price is required" });
+      return;
+    }
+
     const product: Product = {
       displayName,
       customerType,
@@ -610,11 +615,24 @@ export function ProductDialog({
                     <ListSection title="Prices">
                       <PricingSection
                         prices={prices}
-                        onPricesChange={setPrices}
+                        onPricesChange={(newPrices) => {
+                          setPrices(newPrices);
+                          if (errors.prices && Object.keys(newPrices).length > 0) {
+                            setErrors(prev => {
+                              const { prices: _, ...rest } = prev;
+                              return rest;
+                            });
+                          }
+                        }}
                         variant="dialog"
                       />
                     </ListSection>
                   </div>
+                  {errors.prices ? (
+                    <Typography type="p" className="text-destructive text-sm">
+                      {errors.prices}
+                    </Typography>
+                  ) : null}
                 </div>
               </div>
             </StepperPage>

apps/e2e/tests/backend/endpoints/api/v1/payments/block-new-purchases.test.ts

@@ -233,6 +233,16 @@ it("should block switch endpoint when blockNewPurchases is enabled", async ({ ex
 
   const { userId } = await Auth.fastSignUp();
 
+  // Grant planA ownership via server so the switch would otherwise have a valid
+  // source subscription — without this, the endpoint could reject for an unrelated
+  // reason and the test would pass by accident if the block check ever moved.
+  const grantResponse = await niceBackendFetch(`/api/latest/payments/products/user/${userId}`, {
+    method: "POST",
+    accessType: "server",
+    body: { product_id: "planA" },
+  });
+  expect(grantResponse.status).toBe(200);
+
   const switchResponse = await niceBackendFetch(`/api/latest/payments/products/user/${userId}/switch`, {
     method: "POST",
     accessType: "client",