fix(service): Reject resumable tokens without an expiration policy

Co-Authored-By: Lorenzo Cian <17258265+lcian@users.noreply.github.com>

Author: sentry-junior[bot]

objectstore-service/src/backend/tiered.rs

@@ -124,7 +124,7 @@ use base64::Engine as _;
 use bytes::Bytes;
 use futures_util::StreamExt;
 use objectstore_metrics::TimerGuard;
-use objectstore_types::metadata::Metadata;
+use objectstore_types::metadata::{ExpirationPolicy, Metadata};
 use objectstore_types::range::ByteRange;
 use objectstore_types::resumable::UploadProgress;
 use objectstore_types::time::Timestamp;
@@ -490,10 +490,11 @@ type LongTermBackendToken = BackendToken;
 struct TieredResumableToken {
     inner: LongTermBackendToken,
     revision: String,
-    /// Duration of a time-based expiration policy, applied from the commit time.
+    /// Expiration policy requested for the object, applied from the commit time.
     ///
-    /// `None` for manual expiration.
-    expires_in: Option<Duration>,
+    /// Required, so tokens issued before this field existed fail to decode instead of
+    /// committing without an expiry.
+    expiration_policy: ExpirationPolicy,
 }
 
 impl TieredResumableToken {
@@ -582,7 +583,7 @@ impl Backend for TieredStorage {
         let token = TieredResumableToken {
             revision: revision.key,
             inner,
-            expires_in: metadata.expiration_policy.expires_in(),
+            expiration_policy: metadata.expiration_policy,
         };
         Ok(Some(serde_json::to_string(&token).context(
             ErrorKind::Internal,
@@ -605,7 +606,7 @@ impl Backend for TieredStorage {
             backend_type = self.backend_type(&BackendChoice::LongTerm),
         );
         let tiered = TieredResumableToken::decode(&session.backend_token)?;
-        let expires_in = tiered.expires_in;
+        let expires_in = tiered.expiration_policy.expires_in();
         let inner_session = tiered.into_inner_session(session);
         let id = &session.object_id;
         let revision = &inner_session.object_id;
@@ -1807,6 +1808,17 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn resumable_token_requires_expiration_policy() {
+        let legacy = r#"{"inner":"token","revision":"key/rev","time_expires":null}"#;
+        assert_eq!(
+            TieredResumableToken::decode(&legacy.to_owned())
+                .unwrap_err()
+                .kind(),
+            ErrorKind::UnknownUploadSession
+        );
+    }
+
     #[tokio::test]
     async fn resumable_commit_requires_confirmed_expiry() {
         let (storage, hv, _, events) = tiered_with_expiry_hooks(false, true);