Fix pet update functionality - Fixed issue where editing a pet's type…

… or name wasn't persisting - Updated processUpdateForm to modify existing pet instead of adding new one - Added proper handling of existing pet update Fixes #1752

src/main/java/org/springframework/samples/petclinic/owner/PetController.java

@@ -125,11 +125,11 @@ public String initUpdateForm() {
 
 	@PostMapping("/pets/{petId}/edit")
 	public String processUpdateForm(Owner owner, @Valid Pet pet, BindingResult result,
-			RedirectAttributes redirectAttributes) {
+									RedirectAttributes redirectAttributes) {
 
 		String petName = pet.getName();
 
-		// checking if the pet name already exist for the owner
+		// checking if the pet name already exists for the owner
 		if (StringUtils.hasText(petName)) {
 			Pet existingPet = owner.getPet(petName, false);
 			if (existingPet != null && !existingPet.getId().equals(pet.getId())) {
@@ -146,8 +146,21 @@ public String processUpdateForm(Owner owner, @Valid Pet pet, BindingResult resul
 			return VIEWS_PETS_CREATE_OR_UPDATE_FORM;
 		}
 
-		owner.addPet(pet);
-		this.owners.save(owner);
+
+		Pet existingPet = owner.getPet(pet.getId());
+		if (existingPet != null) {
+			// Update existing pet's properties
+			existingPet.setName(pet.getName());
+			existingPet.setBirthDate(pet.getBirthDate());
+			existingPet.setType(pet.getType());
+
+			this.owners.save(owner);
+		} else {
+
+			owner.addPet(pet);
+			this.owners.save(owner);
+		}
+
 		redirectAttributes.addFlashAttribute("message", "Pet details has been edited");
 		return "redirect:/owners/{ownerId}";
 	}