fix(examples): remove proto3 optional to avoid warnings

Remove `optional` keyword from proto files to eliminate the
"proto3 optional" warning from protoc-gen-go-http.

Update main.go implementations to use zero-value checks instead
of nil pointer checks.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: SebastienMelki

examples/multi-service-api/main.go

@@ -100,11 +100,11 @@ func (s *UserServiceImpl) GetCurrentUser(ctx context.Context, req *models.GetCur
 
 func (s *UserServiceImpl) UpdateProfile(ctx context.Context, req *models.UpdateProfileRequest) (*models.User, error) {
 	user := s.users["user-xyz789"]
-	if req.Name != nil {
-		user.Name = *req.Name
+	if req.Name != "" {
+		user.Name = req.Name
 	}
-	if req.AvatarUrl != nil {
-		user.AvatarUrl = *req.AvatarUrl
+	if req.AvatarUrl != "" {
+		user.AvatarUrl = req.AvatarUrl
 	}
 	return user, nil
 }

examples/multi-service-api/proto/models/user.proto

@@ -26,11 +26,11 @@ message GetCurrentUserRequest {}
 
 // UpdateProfileRequest for updating the current user's profile.
 message UpdateProfileRequest {
-  optional string name = 1 [
+  string name = 1 [
     (buf.validate.field).string = { min_len: 2, max_len: 100 },
     (sebuf.http.field_examples) = { values: ["Updated Name"] }
   ];
-  optional string avatar_url = 2 [
+  string avatar_url = 2 [
     (sebuf.http.field_examples) = { values: ["https://example.com/new-avatar.png"] }
   ];
 }

examples/restful-crud/main.go

@@ -186,21 +186,21 @@ func (s *ProductService) PatchProduct(ctx context.Context, req *models.PatchProd
 		return nil, fmt.Errorf("product not found: %s", req.ProductId)
 	}
 
-	// Partial update - only update provided fields
-	if req.Name != nil {
-		product.Name = *req.Name
+	// Partial update - only update non-zero fields
+	if req.Name != "" {
+		product.Name = req.Name
 	}
-	if req.Description != nil {
-		product.Description = *req.Description
+	if req.Description != "" {
+		product.Description = req.Description
 	}
-	if req.Price != nil {
-		product.Price = *req.Price
+	if req.Price != 0 {
+		product.Price = req.Price
 	}
-	if req.StockQuantity != nil {
-		product.StockQuantity = *req.StockQuantity
+	if req.StockQuantity != 0 {
+		product.StockQuantity = req.StockQuantity
 	}
-	if req.CategoryId != nil {
-		product.CategoryId = *req.CategoryId
+	if req.CategoryId != "" {
+		product.CategoryId = req.CategoryId
 	}
 	product.UpdatedAt = time.Now().Unix()
 

examples/restful-crud/proto/models/product.proto

@@ -197,32 +197,32 @@ message PatchProductRequest {
     (sebuf.http.field_examples) = { values: ["123e4567-e89b-12d3-a456-426614174000"] }
   ];
 
-  // Updated name (optional).
-  optional string name = 2 [
+  // Updated name.
+  string name = 2 [
     (buf.validate.field).string = { min_len: 1, max_len: 200 },
     (sebuf.http.field_examples) = { values: ["New Product Name"] }
   ];
 
-  // Updated description (optional).
-  optional string description = 3 [
+  // Updated description.
+  string description = 3 [
     (buf.validate.field).string = { max_len: 2000 },
     (sebuf.http.field_examples) = { values: ["New description"] }
   ];
 
-  // Updated price (optional).
-  optional double price = 4 [
+  // Updated price.
+  double price = 4 [
     (buf.validate.field).double = { gt: 0 },
     (sebuf.http.field_examples) = { values: ["149.99"] }
   ];
 
-  // Updated stock quantity (optional).
-  optional int32 stock_quantity = 5 [
+  // Updated stock quantity.
+  int32 stock_quantity = 5 [
     (buf.validate.field).int32 = { gte: 0 },
     (sebuf.http.field_examples) = { values: ["50"] }
   ];
 
-  // Updated category ID (optional).
-  optional string category_id = 6 [(sebuf.http.field_examples) = { values: ["cat-audio"] }];
+  // Updated category ID.
+  string category_id = 6 [(sebuf.http.field_examples) = { values: ["cat-audio"] }];
 }
 
 // Request to delete a product.

examples/validation-showcase/proto/models/order.proto

@@ -74,9 +74,9 @@ message ContactInfo {
     (sebuf.http.field_examples) = { values: ["+14155551234"] }
   ];
 
-  // Alternative contact name (optional, 2-100 chars if provided).
-  optional string alternative_name = 3 [
-    (buf.validate.field).string = { min_len: 2, max_len: 100 },
+  // Alternative contact name (2-100 chars if provided).
+  string alternative_name = 3 [
+    (buf.validate.field).string = { max_len: 100 },
     (sebuf.http.field_examples) = { values: ["Jane Doe"] }
   ];
 }
@@ -148,7 +148,7 @@ message OrderItem {
   bool gift_wrap = 8 [(sebuf.http.field_examples) = { values: ["false"] }];
 
   // Gift message (if gift_wrap is true, max 500 chars).
-  optional string gift_message = 9 [
+  string gift_message = 9 [
     (buf.validate.field).string = { max_len: 500 },
     (sebuf.http.field_examples) = { values: ["Happy Birthday!"] }
   ];
@@ -251,7 +251,7 @@ message Order {
   PaymentMethod payment_method = 16;
 
   // Special instructions (max 1000 chars).
-  optional string special_instructions = 17 [
+  string special_instructions = 17 [
     (buf.validate.field).string = { max_len: 1000 },
     (sebuf.http.field_examples) = { values: ["Please leave at front door"] }
   ];
@@ -307,7 +307,7 @@ message CreateOrderRequest {
   ];
 
   // Special delivery instructions.
-  optional string special_instructions = 7 [
+  string special_instructions = 7 [
     (buf.validate.field).string = { max_len: 1000 }
   ];