fix: panic in mpool selection (#6325)

LesnyRumcajs · web-flow · commit 27a4609e54fe · 2025-12-10T11:43:29.000Z
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -43,6 +43,8 @@
 
 ### Fixed
 
+- [#6325](https://github.com/ChainSafe/forest/pull/6325) Fixed a panic that could occur under certain message pool conditions and the `Filecoin.MpoolSelect` RPC method.
+
 ## Forest v0.30.4 "DeLorean"
 
 This is a non-mandatory release that fixes a chain sync issue that is caused by time traveling block(s).
diff --git a/src/message_pool/msgpool/selection.rs b/src/message_pool/msgpool/selection.rs
@@ -545,9 +545,8 @@ where
                     if chains[i].cmp_effective(&chains[i + 1]) == Ordering::Greater {
                         break;
                     }
+                    chains.key_vec.swap(i, i + 1);
                 }
-
-                chains.key_vec.swap(i, i + 1);
             }
 
             // select the next (valid and fitting) chain and its dependencies for inclusion

Original file line number	Diff line number	Diff line change
`@@ -545,9 +545,8 @@ where`
`545`	`545`	`if chains[i].cmp_effective(&chains[i + 1]) == Ordering::Greater {`
`546`	`546`	`break;`
`547`	`547`	`}`
	`548`	`+ chains.key_vec.swap(i, i + 1);`
`548`	`549`	`}`
`549`		`-`
`550`		`- chains.key_vec.swap(i, i + 1);`
`551`	`550`	`}`
`552`	`551`
`553`	`552`	`// select the next (valid and fitting) chain and its dependencies for inclusion`