From 8e337478f2943c63eefab4cd45ecc23f4b1e7217 Mon Sep 17 00:00:00 2001
From: E M <5089238+emizzle@users.noreply.github.com>
Date: Wed, 25 Feb 2026 20:13:54 +1100
Subject: [PATCH] Prevent further underflow when deleting blocks

---
 storage/stores/repostore/operations.nim | 2 +-
 storage/stores/repostore/store.nim      | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/storage/stores/repostore/operations.nim b/storage/stores/repostore/operations.nim
index a6fdb992..d83c46b4 100644
--- a/storage/stores/repostore/operations.nim
+++ b/storage/stores/repostore/operations.nim
@@ -157,7 +157,7 @@ proc updateBlockMetadata*(
         BlockMetadata(
           size: currBlockMd.size,
           expiry: max(currBlockMd.expiry, minExpiry),
-          refCount: currBlockMd.refCount + plusRefCount - minusRefCount,
+          refCount: max(0, currBlockMd.refCount + plusRefCount - minusRefCount),
         ).some
       else:
         raise newException(
diff --git a/storage/stores/repostore/store.nim b/storage/stores/repostore/store.nim
index feec3807..6864e0bf 100644
--- a/storage/stores/repostore/store.nim
+++ b/storage/stores/repostore/store.nim
@@ -272,7 +272,8 @@ method delBlock*(
     error "Failed to delete leaf metadata, block will remain on disk.", err = err.msg
     return failure(err)
 
-  if err =?
+  if leafMd.blkCid.mcodec == BlockCodec and 
+     err =?
       (await self.updateBlockMetadata(leafMd.blkCid, minusRefCount = 1)).errorOption:
     if not (err of BlockNotFoundError):
       return failure(err)