From 37f641f79be135cbd956d7a29c7f36a06f97a4fe Mon Sep 17 00:00:00 2001
From: Dominik Maier <domenukk@gmail.com>
Date: Tue, 22 Jun 2021 18:41:46 +0200
Subject: [PATCH] Metadata lookup once (#186)

* metadata lookup once

* fix clippy
---
 libafl/src/bolts/serdeany.rs | 2 +-
 libafl/src/observers/cmp.rs  | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/libafl/src/bolts/serdeany.rs b/libafl/src/bolts/serdeany.rs
index bb545a6cb4..9e6decbea4 100644
--- a/libafl/src/bolts/serdeany.rs
+++ b/libafl/src/bolts/serdeany.rs
@@ -7,7 +7,7 @@ use core::any::{Any, TypeId};
 
 // yolo
 
-/// Get a `type_id` from it's previously unpacked `u64`.
+/// Get a `type_id` from its previously unpacked `u64`.
 /// Opposite of [`unpack_type_id(id)`].
 ///
 /// # Safety
diff --git a/libafl/src/observers/cmp.rs b/libafl/src/observers/cmp.rs
index 3c7cb53061..0affc220e5 100644
--- a/libafl/src/observers/cmp.rs
+++ b/libafl/src/observers/cmp.rs
@@ -113,10 +113,13 @@ where
     where
         S: HasMetadata,
     {
-        if state.metadata().get::<CmpValuesMetadata>().is_none() {
+        #[allow(clippy::clippy::option_if_let_else)] // we can't mutate state in a closure
+        let meta = if let Some(meta) = state.metadata_mut().get_mut::<CmpValuesMetadata>() {
+            meta
+        } else {
             state.add_metadata(CmpValuesMetadata::new());
-        }
-        let meta = state.metadata_mut().get_mut::<CmpValuesMetadata>().unwrap();
+            state.metadata_mut().get_mut::<CmpValuesMetadata>().unwrap()
+        };
         meta.list.clear();
         let count = self.usable_count();
         for i in 0..count {