From 1df16c0394e4168927c9475884b93f6bd1b4b53f Mon Sep 17 00:00:00 2001
From: "Michael P. Jung" <michael.jung@terreon.de>
Date: Mon, 9 Dec 2024 16:53:05 +0000
Subject: [PATCH] Change retain() function to accept a FnMut

This closes #370
---
 src/managed/mod.rs |  2 +-
 tests/managed.rs   | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/managed/mod.rs b/src/managed/mod.rs
index 3c35ade..c7dd35f 100644
--- a/src/managed/mod.rs
+++ b/src/managed/mod.rs
@@ -519,7 +519,7 @@ impl<M: Manager, W: From<Object<M>>> Pool<M, W> {
     ///     }
     /// });
     /// ```
-    pub fn retain(&self, f: impl Fn(&M::Type, Metrics) -> bool) {
+    pub fn retain(&self, mut f: impl FnMut(&M::Type, Metrics) -> bool) {
         let mut guard = self.inner.slots.lock().unwrap();
         let len_before = guard.vec.len();
         guard.vec.retain_mut(|obj| {
diff --git a/tests/managed.rs b/tests/managed.rs
index adf8613..3aeb750 100644
--- a/tests/managed.rs
+++ b/tests/managed.rs
@@ -297,3 +297,22 @@ async fn retain() {
     pool.retain(|_, metrics| metrics.age() <= Duration::from_millis(10));
     assert_eq!(pool.status().size, 0);
 }
+
+#[tokio::test]
+async fn retain_fnmut() {
+    let mgr = Manager {};
+    let pool = Pool::builder(mgr).max_size(4).build().unwrap();
+    {
+        let _a = pool.get().await;
+        let _b = pool.get().await;
+        let _c = pool.get().await;
+        let _c = pool.get().await;
+    }
+    let mut removed = 0;
+    {
+        pool.retain(|_, _| {
+            removed += 1;
+            false
+        });
+    }
+}