refactor(rust): drop variable rebinding in s3 cache and bridge config

Also adds the startup_nodes parameter to the _CacheTestHandle.redis stub to match the merged runtime signature

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm-rust/crates/cache-s3/src/cache.rs

@@ -42,16 +42,17 @@ pub struct S3Cache<C: CacheCodec> {
 
 impl<C: CacheCodec> S3Cache<C> {
     pub fn new(config: S3CacheConfig, codec: C, runtime: Handle) -> Self {
-        let mut builder = aws_sdk_s3::Config::builder()
+        let endpoint_url: Option<String> = config.endpoint.map(|endpoint| endpoint.url);
+        let base = aws_sdk_s3::Config::builder()
             .behavior_version(BehaviorVersion::latest())
             .region(Region::new(config.region.clone()))
             .credentials_provider(Credentials::new(config.auth))
             .request_checksum_calculation(RequestChecksumCalculation::WhenRequired)
             .response_checksum_validation(ResponseChecksumValidation::WhenRequired);
-        let endpoint_url: Option<String> = config.endpoint.map(|endpoint| endpoint.url);
-        if let Some(url) = &endpoint_url {
-            builder = builder.endpoint_url(url).force_path_style(true);
-        }
+        let builder = match &endpoint_url {
+            Some(url) => base.endpoint_url(url).force_path_style(true),
+            None => base,
+        };
         Self {
             client: aws_sdk_s3::Client::from_conf(builder.build()),
             codec,

litellm-rust/crates/python-bridge/src/cache/config.rs

@@ -642,14 +642,12 @@ fn optional_attribute_chain<'py>(
     value: &Bound<'py, PyAny>,
     names: &[&str],
 ) -> PyResult<Option<Bound<'py, PyAny>>> {
-    let mut current = value.clone();
-    for name in names {
-        match optional_attribute(&current, name)? {
-            Some(next) => current = next,
-            None => return Ok(None),
-        }
-    }
-    Ok(Some(current))
+    names
+        .iter()
+        .try_fold(Some(value.clone()), |current, name| match current {
+            Some(current) => optional_attribute(&current, name),
+            None => Ok(None),
+        })
 }
 
 #[inline(never)]

litellm/rust_bridge/_native.pyi

@@ -162,6 +162,7 @@ class _CacheTestHandle:
         *,
         ttl_seconds: float = 60.0,
         namespace: str | None = None,
+        startup_nodes: Sequence[tuple[str, int]] | None = None,
     ) -> _CacheTestHandle: ...
     @staticmethod
     def s3(