Delete a data object on PUT DATA with an empty object

CHANGELOG.md

@@ -8,6 +8,7 @@
   default (5)
 - Fix the inverted parsing of the touch requirement in SET MANAGEMENT KEY's P2
   (0xFF means no touch, 0xFE means touch required)
+- Delete a data object on PUT DATA with an empty object
 
 ## [v0.7.0][] (2026-08-17)
 

src/lib.rs

@@ -1012,6 +1012,11 @@ impl<T: Client> LoadedAuthenticator<'_, T> {
         };
 
         use state::ContainerStorage;
+        // An empty object deletes
+        if data.is_empty() {
+            ContainerStorage(container).remove(self.trussed, self.options.storage);
+            return Ok(());
+        }
         ContainerStorage(container).save(self.trussed, data, self.options.storage)
     }
 

src/state.rs

@@ -1181,7 +1181,8 @@ impl ContainerStorage {
 
     fn default(self) -> Option<Vec<u8, MAX_MESSAGE_LENGTH>> {
         match self.0 {
-            Container::CardHolderUniqueIdentifier => panic!("CHUID should alway be set"),
+            // Written at initialization, absent only once deleted
+            Container::CardHolderUniqueIdentifier => None,
             Container::CardCapabilityContainer => Some(Vec::from_slice(&CARD_CAP).unwrap()),
             Container::DiscoveryObject => Some(Vec::from_slice(&DISCOVERY_OBJECT).unwrap()),
             Container::PrintedInformation => Some(Vec::from_slice(&PRINTED_INFORMATION).unwrap()),
@@ -1250,6 +1251,17 @@ impl ContainerStorage {
         }
     }
 
+    pub fn remove(self, client: &mut impl crate::Client, storage: Location) {
+        // Already absent is fine
+        try_syscall!(client.remove_file(storage, self.path())).ok();
+        if matches!(
+            self.0.contact_access_rule(),
+            ReadAccessRule::PinOrOcc | ReadAccessRule::Pin
+        ) {
+            try_syscall!(client.remove_file(storage, self.path_key())).ok();
+        }
+    }
+
     pub fn save(
         self,
         client: &mut impl crate::Client,

tests/command_response.ron

@@ -255,6 +255,71 @@
             )
         ]
     ),
+    IoTest(
+        name: "Empty PUT DATA deletes",
+        cmd_resp: [
+            AuthenticateManagement(
+                key: (
+                    algorithm: Tdes,
+                    key: "0102030405060708 0102030405060708 0102030405060708"
+                ),
+                mutual: false,
+            ),
+            PutData(
+                input: "5C 03 5FC10B 53 04 00010203",
+            ),
+            GetData(
+                input: "5C 03 5FC10B",
+                output: Data("53 04 00010203")
+            ),
+            PutData(
+                input: "5C 03 5FC10B 53 00",
+            ),
+            GetData(
+                input: "5C 03 5FC10B",
+                output: All(),
+                expected_status: NotFound
+            ),
+            PutData(
+                input: "5C 03 5FC10D 53 04 00010203",
+            ),
+            GetData(
+                input: "5C 03 5FC10C",
+                output: Data("53 08 C1 01 01 C2 01 00 FE 00")
+            ),
+            PutData(
+                input: "5C 03 5FC10D 53 00",
+            ),
+            GetData(
+                input: "5C 03 5FC10C",
+                output: Data("53 08 C1 01 00 C2 01 00 FE 00")
+            ),
+            PutData(
+                input: "5C 03 5FC103 53 04 00010203",
+            ),
+            VerifyApplicationPin(),
+            GetData(
+                input: "5C 03 5FC103",
+                output: Data("53 04 00010203")
+            ),
+            PutData(
+                input: "5C 03 5FC103 53 00",
+            ),
+            GetData(
+                input: "5C 03 5FC103",
+                output: All(),
+                expected_status: NotFound
+            ),
+            PutData(
+                input: "5C 03 5FC102 53 00",
+            ),
+            GetData(
+                input: "5C 03 5FC102",
+                output: All(),
+                expected_status: NotFound
+            ),
+        ]
+    ),
     IoTest(
         name: "PUT DATA",
         cmd_resp: [