chore(ecstore): drop the cluster and erasure dead_code blankets

Removing both blankets exposes 23 items, of which only four are deleted. The ratio is the point: close to the core data path the blankets were hiding test assertions and migration seams, not dead code.

A cfg-split function is the reason two symbols in the internode transport look dead when neither is. build_internode_data_transport_from_env has two bodies, one under #[cfg(test)] that calls build_internode_data_transport directly and one under #[cfg(not(test))] that goes through the INTERNODE_DATA_TRANSPORT static so tests do not share process-global transport state. Each half's helper is live in exactly one build, and because cargo check --tests compiles both the lib target and the test harness, both symbols appear in one warning list. Deleting either one breaks the other lane. Both are kept with allows naming their half.

Three deletion candidates were withdrawn after a per-name grep: ParallelReader::new, ErasureDecodeReader::new and SyncErasureDecodeReader::new all have test callers. The last two are exactly the shape of the dead wrapper deleted in #6084 — a thin forward to a new_with_metrics_path sibling — except that sibling is live in production (set_disk/read.rs) and the wrappers are used by tests.

Deleted:

- RemotePeerS3Client::get_addr and RemoteLocker::from_url, neither with a consumer in any lane.
- RemotePeerS3Client's node field, which new writes after using it to derive addr and nothing ever reads. Its only other writer was a test helper that built a whole Node solely to fill the field; that block goes too.
- ParallelReader::can_decode, superseded by an inlined copy. The copy's comment named the method it replaced, so deleting the method alone would have left a dangling reference; the comment now describes the check instead of pointing at a method that no longer exists.

Kept with allows: the erasure items are decode/encode invariants asserted by their own files' tests (shard_read_launch_order, decode_with_read_costs, emit_data_shards, queued_block_bytes, the engine trait facets, the ParallelReader and decode-reader constructors, encode_stream_callback_async). On the cluster side, peer_replay_state, heal_bucket_local and clone_drives are test-only, InternodeDataTransportCapabilities and tcp_http are constructed only by transport test doubles, and the InternodeDataTransport trait's name/capabilities pair is an unused capability-negotiation facet kept for the transport split (backlog#1350) — six impls provide them and no caller negotiates on them yet.

Verification, four lanes warning-free: default, --tests, --features rio-v2 --tests, --features test-util --tests. cargo nextest run -p rustfs-ecstore 4041 passed; clippy --lib --tests -D warnings clean; make pre-commit exit 0.

Ref rustfs/backlog#1823 (step 2).

crates/ecstore/src/cluster/mod.rs

@@ -13,7 +13,6 @@
 // limitations under the License.
 
 // #730: cluster/RPC migration leaves transport capabilities staged for upcoming owners.
-#![allow(dead_code)]
 
 mod control_plane;
 pub(crate) mod rpc;

crates/ecstore/src/cluster/rpc/client.rs

@@ -256,6 +256,7 @@ impl<S> ReplayScopeChannel<S> {
     }
 }
 
+#[allow(dead_code, reason = "replay-state probe asserted by this file's tests (backlog#1823)")]
 fn peer_replay_state(audience: &str) -> PeerReplayState {
     PEER_REPLAY_STATES
         .lock()

crates/ecstore/src/cluster/rpc/internode_data_transport.rs

@@ -43,6 +43,10 @@ use tokio::io::{AsyncReadExt, AsyncWrite};
 use tokio::sync::OnceCell;
 use uuid::Uuid;
 
+#[allow(
+    dead_code,
+    reason = "live in the cfg(not(test)) half of build_internode_data_transport_from_env (backlog#1823)"
+)]
 static INTERNODE_DATA_TRANSPORT: OnceLock<std::result::Result<Arc<dyn InternodeDataTransport>, String>> = OnceLock::new();
 
 const READ_FILE_STREAM_PATH: &str = "/rustfs/rpc/read_file_stream";
@@ -134,6 +138,10 @@ fn put_file_capability_status_is_legacy(status: u16) -> bool {
 }
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
+#[allow(
+    dead_code,
+    reason = "capability-negotiation seam; constructed only by transport test doubles (backlog#1823)"
+)]
 pub struct InternodeDataTransportCapabilities {
     /// Backend can open a streaming remote disk reader.
     pub streaming_read: bool,
@@ -150,6 +158,10 @@ pub struct InternodeDataTransportCapabilities {
 }
 
 impl InternodeDataTransportCapabilities {
+    #[allow(
+        dead_code,
+        reason = "capability-negotiation seam; used by transport test doubles (backlog#1823)"
+    )]
     pub const fn tcp_http() -> Self {
         Self {
             streaming_read: true,
@@ -234,7 +246,12 @@ pub trait InternodeDataTransport: Send + Sync + std::fmt::Debug {
     async fn probe_ns_scanner(&self, _request: NsScannerCapabilityRequest) -> Result<Uuid> {
         Err(Error::MethodNotAllowed)
     }
+    // Interface facet nobody calls yet: every transport implements both, but no
+    // caller negotiates on them. Kept for the internode transport split
+    // (backlog#1350); deleting them would delete the seam and six impls.
+    #[allow(dead_code, reason = "unused capability-negotiation facet (backlog#1823)")]
     fn name(&self) -> &'static str;
+    #[allow(dead_code, reason = "unused capability-negotiation facet (backlog#1823)")]
     fn capabilities(&self) -> InternodeDataTransportCapabilities;
 }
 
@@ -670,6 +687,10 @@ fn build_internode_data_transport_result(
     }
 }
 
+#[allow(
+    dead_code,
+    reason = "live in the cfg(test) half of build_internode_data_transport_from_env, which bypasses the process static (backlog#1823)"
+)]
 pub fn build_internode_data_transport(configured_transport: Option<&str>) -> Result<Arc<dyn InternodeDataTransport>> {
     build_internode_data_transport_result(configured_transport).map_err(Error::other)
 }

crates/ecstore/src/cluster/rpc/peer_s3_client.rs

@@ -854,7 +854,6 @@ impl PeerS3Client for LocalPeerS3Client {
 
 #[derive(Debug)]
 pub struct RemotePeerS3Client {
-    pub node: Option<Node>,
     pub pools: Option<Vec<usize>>,
     addr: String,
     /// Health tracker for connection monitoring
@@ -886,7 +885,6 @@ impl RemotePeerS3Client {
     pub fn new(node: Option<Node>, pools: Option<Vec<usize>>) -> Self {
         let addr = node.as_ref().map(|v| v.url.to_string()).unwrap_or_default();
         let client = Self {
-            node,
             pools,
             addr,
             health: Arc::new(DiskHealthTracker::new()),
@@ -905,10 +903,6 @@ impl RemotePeerS3Client {
             .map_err(|err| Error::other(format!("can not get client, err: {err}")))
     }
 
-    pub fn get_addr(&self) -> String {
-        self.addr.clone()
-    }
-
     /// Start health monitoring for the remote peer
     fn start_health_monitoring(&self) {
         let health = Arc::clone(&self.health);
@@ -1208,6 +1202,10 @@ impl PeerS3Client for RemotePeerS3Client {
     }
 }
 
+#[allow(
+    dead_code,
+    reason = "local bucket-heal path reached only by this file's tests (backlog#1823)"
+)]
 pub async fn heal_bucket_local(bucket: &str, opts: &HealOpts) -> Result<HealResultItem> {
     let disks = clone_drives().await;
     heal_bucket_local_on_disks(bucket, opts, disks).await
@@ -1404,6 +1402,10 @@ pub(crate) async fn heal_bucket_local_on_disks(
     }
 }
 
+#[allow(
+    dead_code,
+    reason = "reached only through heal_bucket_local, which only tests call (backlog#1823)"
+)]
 async fn clone_drives() -> Vec<Option<DiskStore>> {
     runtime_sources::local_disk_entries().await
 }
@@ -1585,15 +1587,7 @@ mod tests {
     }
 
     fn test_remote_peer(addr: &str) -> RemotePeerS3Client {
-        let node = Node {
-            url: url::Url::parse(addr).expect("test peer URL should parse"),
-            pools: vec![0],
-            is_local: false,
-            grid_host: addr.to_string(),
-        };
-
         RemotePeerS3Client {
-            node: Some(node),
             pools: Some(vec![0]),
             addr: addr.to_string(),
             health: Arc::new(DiskHealthTracker::new()),

crates/ecstore/src/cluster/rpc/remote_locker.rs

@@ -48,10 +48,6 @@ impl RemoteClient {
         Self { addr: endpoint }
     }
 
-    pub fn from_url(url: url::Url) -> Self {
-        Self { addr: url.to_string() }
-    }
-
     fn build_ping_request() -> PingRequest {
         let mut fbb = flatbuffers::FlatBufferBuilder::new();
         let payload = fbb.create_vector(b"health-check");

crates/ecstore/src/erasure/codec/bridge.rs

@@ -26,6 +26,7 @@ pub(crate) const GET_RECONSTRUCT_OUTCOME_SKIP_DATA_COMPLETE: &str = "skip_data_c
 pub(crate) const GET_RECONSTRUCT_OUTCOME_SKIP_EMPTY_PAYLOAD: &str = "skip_empty_payload";
 
 pub(crate) trait DecodeWorkspace: Send + Sync + 'static {
+    #[allow(dead_code, reason = "workspace width asserted by decode_reader tests (backlog#1823)")]
     fn shard_len(&self) -> usize;
 }
 
@@ -33,11 +34,14 @@ pub(crate) trait ErasureDecodeEngine: Send + Sync + 'static {
     type Workspace: DecodeWorkspace;
 
     fn data_shards(&self) -> usize;
+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
     fn parity_shards(&self) -> usize;
     fn block_size(&self) -> usize;
     fn engine_name(&self) -> &'static str;
 
+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
     fn supports_progressive_decode(&self) -> bool;
+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
     fn supports_aligned_shards(&self) -> bool;
 
     fn prepare_workspace(&self, shard_len: usize) -> io::Result<Self::Workspace>;

crates/ecstore/src/erasure/codec/workspace.rs

@@ -24,6 +24,7 @@ impl RustfsCodecDecodeWorkspace {
     }
 
     #[inline]
+    #[allow(dead_code, reason = "workspace width asserted by decode_reader tests (backlog#1823)")]
     pub(crate) fn shard_len(&self) -> usize {
         self.shard_len
     }

crates/ecstore/src/erasure/coding/decode.rs

@@ -213,6 +213,7 @@ fn shard_read_launch_rank(cost: ShardReadCost) -> u8 {
     }
 }
 
+#[allow(dead_code, reason = "launch ordering asserted by this file's tests (backlog#1823)")]
 fn shard_read_launch_order(read_costs: &[ShardReadCost], num_readers: usize, locality_preference_enabled: bool) -> Vec<usize> {
     let mut order: Vec<usize> = (0..num_readers).collect();
     if locality_preference_enabled {
@@ -408,6 +409,10 @@ where
     R: crate::erasure::coding::ShardSource,
 {
     // Readers should handle disk errors before being passed in, ensuring each reader reaches the available number of BitrotReaders
+    #[allow(
+        dead_code,
+        reason = "ParallelReader constructor used only by this file's tests (backlog#1823)"
+    )]
     pub fn new(readers: Vec<Option<BitrotReader<R>>>, e: Erasure, offset: usize, total_length: usize) -> Self {
         Self::new_with_metrics_path_read_timeout_and_reconstruction_verification(
             readers,
@@ -420,6 +425,7 @@ where
         )
     }
 
+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
     pub fn new_with_metrics_path(
         readers: Vec<Option<BitrotReader<R>>>,
         e: Erasure,
@@ -438,6 +444,7 @@ where
         )
     }
 
+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
     pub fn new_with_metrics_path_and_read_costs(
         readers: Vec<Option<BitrotReader<R>>>,
         e: Erasure,
@@ -514,6 +521,7 @@ where
         )
     }
 
+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
     fn new_with_read_timeout(
         readers: Vec<Option<BitrotReader<R>>>,
         e: Erasure,
@@ -1330,10 +1338,6 @@ where
             }
         }
     }
-
-    pub fn can_decode(&self, shards: &[Option<Vec<u8>>]) -> bool {
-        shards.iter().filter(|s| s.is_some()).count() >= self.data_shards
-    }
 }
 
 #[async_trait::async_trait]
@@ -1539,6 +1543,7 @@ impl Erasure {
             .await
     }
 
+    #[allow(dead_code, reason = "read-cost decode path asserted by this file's tests (backlog#1823)")]
     pub(crate) async fn decode_with_read_costs<W, R>(
         &self,
         writer: &mut W,
@@ -1609,9 +1614,9 @@ impl Erasure {
             *ret_err = Some(err.into());
         }
 
-        // Equivalent to `ParallelReader::can_decode`; inlined so this helper does
-        // not need to borrow the reader, leaving the reader free for the
-        // concurrent next-stripe read under prefetch.
+        // Shard-availability check, written out here rather than called on the
+        // reader so this helper does not need to borrow it, leaving the reader
+        // free for the concurrent next-stripe read under prefetch.
         let available_shards = shards.iter().filter(|shard| shard.is_some()).count();
         if available_shards < self.data_shards {
             let reason = GetObjectFailureReason::ReadQuorum;

crates/ecstore/src/erasure/coding/decode_reader.rs

@@ -138,6 +138,10 @@ where
     S: ShardStripeSource + Send + 'static,
     E: ErasureDecodeEngine + Clone + Send + Sync + 'static,
 {
+    #[allow(
+        dead_code,
+        reason = "default-metrics-path constructor used only by this file's tests (backlog#1823)"
+    )]
     pub(crate) fn new(source: S, engine: E, total_length: usize) -> io::Result<Self> {
         Self::new_with_metrics_path(source, engine, total_length, GET_OBJECT_PATH_CODEC_STREAMING)
     }
@@ -679,6 +683,10 @@ pub(crate) struct SyncErasureDecodeReader<R> {
 }
 
 impl<R> SyncErasureDecodeReader<R> {
+    #[allow(
+        dead_code,
+        reason = "default-metrics-path constructor used only by this file's tests (backlog#1823)"
+    )]
     pub(crate) fn new(inner: R) -> Self {
         Self::new_with_metrics_path(inner, GET_OBJECT_PATH_CODEC_STREAMING)
     }
@@ -805,6 +813,7 @@ where
     Ok(true)
 }
 
+#[allow(dead_code, reason = "shard emission asserted by this file's tests (backlog#1823)")]
 fn emit_data_shards(state: &StripeReadState, data_shards: usize, block_size: usize, remaining: usize) -> io::Result<Vec<u8>> {
     let mut output = Vec::new();
     emit_data_shards_into(state, data_shards, block_size, remaining, &mut output)?;

crates/ecstore/src/erasure/coding/encode.rs

@@ -166,6 +166,7 @@ where
     if total == 0 { Ok(None) } else { Ok(Some(total)) }
 }
 
+#[allow(dead_code, reason = "byte accounting asserted by this file's tests (backlog#1823)")]
 fn queued_block_bytes(block: &[Bytes]) -> usize {
     block.iter().map(Bytes::len).sum()
 }

crates/ecstore/src/erasure/coding/erasure.rs

@@ -1110,6 +1110,10 @@ impl Erasure {
     ///
     /// # Errors
     /// Returns error if reading from reader fails or if callback returns error
+    #[allow(
+        dead_code,
+        reason = "callback encode path exercised only by this file's tests (backlog#1823)"
+    )]
     pub(crate) async fn encode_stream_callback_async<F, Fut, E, R>(
         self: std::sync::Arc<Self>,
         reader: &mut R,

crates/ecstore/src/erasure/mod.rs

@@ -13,7 +13,6 @@
 // limitations under the License.
 
 // #730: erasure codec migration keeps staged streaming decode paths in this module.
-#![allow(dead_code)]
 
 pub(crate) mod codec;
 pub(crate) mod coding;