fix: popitem() returns expired entry in TTLCache/VTTLCache

pyproject.toml

@@ -55,8 +55,8 @@ lint = [
   "ruff>=0.16.9",
 ]
 maturin = [
-  "maturin == 1.14.1 ; sys_platform != 'linux'",
-  "maturin[patchelf] == 1.14.1 ; sys_platform == 'linux'",
+  "maturin == 1.15.0 ; sys_platform != 'linux'",
+  "maturin[patchelf] == 1.15.0 ; sys_platform == 'linux'",
 ]
 test = [
   "hypothesis >= 6.165.0",

src/policies/ttlpolicy.rs

@@ -422,12 +422,11 @@ impl PolicyExt for TTLPolicy {
     }
 
     fn evict(&mut self, shared: &Self::Shared) -> pyo3::PyResult<Self::Handle> {
-        let front = self.entries.front();
-        if front.is_none() {
-            return Err(new_py_error!(PyKeyError, ()));
-        }
+        self.expire(shared.generation_version());
 
-        let front = unsafe { front.unwrap_unchecked() };
+        let Some(front) = self.entries.front() else {
+            return Err(new_py_error!(PyKeyError, ()));
+        };
 
         let eq = |index: &usize| Ok::<_, pyo3::PyErr>(*index - self.front_offset == 0);
         let removed_key_table = self.table.remove_entry(front.key().hash(), eq).unwrap();

src/policies/vttlpolicy.rs

@@ -391,11 +391,12 @@ impl PolicyExt for VTTLPolicy {
     }
 
     fn evict(&mut self, shared: &Self::Shared) -> pyo3::PyResult<Self::Handle> {
+        self.expire(shared.generation_version());
+
         {
-            let front_cursor = self
-                .heap
-                .front()
-                .ok_or_else(|| new_py_error!(PyKeyError, "cache is empty"))?;
+            let Some(front_cursor) = self.heap.front() else {
+                return Err(new_py_error!(PyKeyError, "cache is empty"));
+            };
 
             self.table
                 .remove_entry(unsafe { front_cursor.element().key.hash() }, |x| {

tests/test_impls.py

@@ -1312,6 +1312,23 @@ def test_popitem_removes_oldest(self):
         assert key == 10
         assert value == "x"
 
+    def test_popitem_expire_keys(self):
+        """popitem() must always expire all expired keys, and return the oldest *alive* inserted entry."""
+        cache = self.create_cache(5, global_ttl=0.5)
+
+        cache.insert(1, "a")
+        cache.insert(2, "b")
+
+        time.sleep(0.5)
+
+        cache.insert(3, "c")
+        cache.insert(4, "d")
+        cache.insert(5, "e")
+
+        key, value = cache.popitem()
+        assert key == 3
+        assert value == "c"
+
     def test_popitem_successive_calls_follow_fifo(self):
         """Successive popitem() calls must yield keys in insertion order."""
         insertion_order = [(1, "a"), (2, "b"), (3, "c"), (4, "d")]
@@ -1932,6 +1949,22 @@ def test_popitem_on_empty_raises(self):
         with pytest.raises(KeyError):
             c.popitem()
 
+    def test_popitem_expire_keys(self):
+        """popitem() must always expire all expired keys, and return the soonest expiring *alive* inserted entry."""
+        cache = self.create_cache(5)
+
+        cache.insert(1, "a", ttl=0.5)
+        cache.insert(2, "b", ttl=2)
+        cache.insert(3, "c", ttl=None)
+        cache.insert(4, "d", ttl=0.1)
+        cache.insert(5, "e", ttl=3)
+
+        time.sleep(0.5)
+
+        key, value = cache.popitem()
+        assert key == 2
+        assert value == "b"
+
     def test_popitem_follows_expiry_after_ttl_changes(self):
         c = cachebox.VTTLCache(10)
         c.insert("a", 1, ttl=100)