From ab85c03f50144b7f1718200e5d68c489dab69963 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Sun, 1 Mar 2026 21:04:36 +0100
Subject: fix resume on reverse value index

---
 database/src/kv/index.rs | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

(limited to 'database')

diff --git a/database/src/kv/index.rs b/database/src/kv/index.rs
index dd2471b..5505079 100644
--- a/database/src/kv/index.rs
+++ b/database/src/kv/index.rs
@@ -127,17 +127,21 @@ pub fn iter_index<'a>(
         }
         Sort::Value(value_sort) => {
             assert!(value_sort.offset.is_none(), "TODO");
-            let mut start = prefix.clone();
+            let (mut start, rev) = match value_sort.order {
+                SortOrder::Ascending => (prefix.clone(), false),
+                SortOrder::Descending => (inc_key(prefix.clone()), true),
+            };
             if let Some(resume) = resume {
-                start.extend(resume);
-                start = inc_key(start);
+                start = prefix.iter().copied().chain(resume).collect();
+                if rev {
+                    start = dec_key(start);
+                } else {
+                    start = inc_key(start);
+                }
             }
             Box::new(
                 PrefixIterator {
-                    inner: match value_sort.order {
-                        SortOrder::Ascending => txn.iter(&start, false)?,
-                        SortOrder::Descending => txn.iter(&inc_key(prefix.clone()), true)?,
-                    },
+                    inner: txn.iter(&start, rev)?,
                     prefix: prefix.clone().into(),
                 }
                 .map(move |k| {
@@ -164,6 +168,16 @@ fn inc_key(mut k: Vec<u8>) -> Vec<u8> {
     }
     k
 }
+fn dec_key(mut k: Vec<u8>) -> Vec<u8> {
+    for v in k.iter_mut().rev() {
+        let (nv, carry) = v.overflowing_sub(1);
+        *v = nv;
+        if !carry {
+            break;
+        }
+    }
+    k
+}
 
 fn randomize(mut x: u64) -> u64 {
     for _ in 0..15 {
-- 
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