test ancient append vecs with dead slots (#28800)

runtime/src/accounts_db.rs

@@ -17679,8 +17679,11 @@ pub mod tests {
 
     #[test]
     fn test_combine_ancient_slots_append() {
+        solana_logger::setup();
         // combine 2-4 slots into a single ancient append vec
         for num_normal_slots in 1..3 {
+            // but some slots contain only dead accounts
+            for dead_accounts in 0..=num_normal_slots {
                 let mut originals = Vec::default();
                 // ancient_slot: contains ancient append vec
                 // ancient_slot + 1: contains normal append vec with 1 alive account
@@ -17693,6 +17696,30 @@ pub mod tests {
                     originals.push(db.get_storages_for_slot(slot).unwrap());
                 }
 
+                {
+                    // remove the intended dead slots from the index so they look dead
+                    for (count_marked_dead, original) in originals.iter().skip(1).enumerate() {
+                        // skip the ancient one
+                        if count_marked_dead >= dead_accounts {
+                            break;
+                        }
+                        let original = original.first().unwrap();
+                        let original = original.accounts.account_iter().next().unwrap();
+                        let slot = ancient_slot + 1 + (count_marked_dead as Slot);
+                        _ = db.purge_keys_exact(
+                            [(
+                                *original.pubkey(),
+                                vec![slot].into_iter().collect::<HashSet<_>>(),
+                            )]
+                            .iter(),
+                        );
+                    }
+                    // the entries from these original append vecs should not expect to be in the final ancient append vec
+                    for _ in 0..dead_accounts {
+                        originals.remove(1); // remove the first non-ancient original entry each time
+                    }
+                }
+
                 // combine normal append vec(s) into existing ancient append vec
                 db.combine_ancient_slots(
                     (ancient_slot..=max_slot_inclusive).collect(),
@@ -17716,19 +17743,26 @@ pub mod tests {
                     stored_accounts: mut after_stored_accounts,
                     ..
                 } = db.get_unique_accounts_from_storages(std::iter::once(&ancient));
-            assert_eq!(after_stored_accounts.len(), num_normal_slots + 1);
+                assert_eq!(
+                    after_stored_accounts.len(),
+                    num_normal_slots + 1 - dead_accounts,
+                    "normal_slots: {num_normal_slots}, dead_accounts: {dead_accounts}"
+                );
                 for original in &originals {
                     let original = original.first().unwrap();
                     let original = original.accounts.account_iter().next().unwrap();
-                for i in 0..=after_stored_accounts.len() {
+
-                    assert_ne!(after_stored_accounts.len(), i, "did not find account");
+                    let i = after_stored_accounts
-                    let stored_ancient = &after_stored_accounts[i];
+                        .iter()
-                    if stored_ancient.pubkey() == original.pubkey() {
+                        .enumerate()
+                        .find_map(|(i, stored_ancient)| {
+                            (stored_ancient.pubkey() == original.pubkey()).then_some({
                                 assert!(accounts_equal(&stored_ancient.account, &original));
+                                i
+                            })
+                        })
+                        .expect("did not find account");
                     after_stored_accounts.remove(i);
-                        break;
-                    }
-                }
                 }
                 assert!(
                     after_stored_accounts.is_empty(),
@@ -17738,6 +17772,7 @@ pub mod tests {
                 );
             }
         }
+    }
 
     fn get_one_ancient_append_vec_and_others(
         alive: bool,