refactor: consolidate app object store fallback (#3445)

crates/ecstore/src/tier/tier.rs

@@ -994,7 +994,6 @@ impl TierConfigMgr {
     }
 
     pub async fn reload(&mut self, api: Arc<ECStore>) -> std::result::Result<(), std::io::Error> {
-        //let Some(api) = new_object_layer_fn() else { return Err(Error::msg("errServerNotInitialized")) };
         let new_config = load_tier_config(api).await;
 
         match &new_config {

docs/architecture/migration-progress.md

@@ -5,19 +5,18 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 ## Current Context
 
 - Issue: [`rustfs/backlog#660`](https://github.com/rustfs/backlog/issues/660)
-- Branch: `overtrue/arch-ecstore-internal-object-store-resolver`
-- Baseline: `upstream/main` at `8f6b1d47b5af689e0b3576ab4448cc4274786df1`
+- Branch: `overtrue/arch-app-usecase-object-store-fallback-cleanup`
+- Baseline: `origin/main` at `fc894c9b569229101f859a6c4097eb64d3f86f5c`
 - PR type for this branch: `consumer-migration`
-- Runtime behavior changes: no external behavior change expected; ECStore
-  internal/background object-store lookups prefer the AppContext-owned object
-  store through the ECStore-owned resolver and keep the existing global
-  fallback.
-- Rust code changes: migrate ECStore internal metrics, notification, tier,
-  decommission, admin info, bucket metadata, replication, lifecycle, and data
-  usage object-store lookups to the ECStore-owned resolver without touching app
-  compatibility fallbacks or the global fallback definition.
+- Runtime behavior changes: no external behavior change expected; app usecase
+  object-store lookups share the same explicit-context resolver and keep the
+  existing legacy global object-layer fallback when no usecase context exists.
+- Rust code changes: add an explicit AppContext object-store resolver helper,
+  migrate admin, bucket, multipart, and object usecases to it, and remove a
+  stale ECStore tier comment that referenced the old direct accessor.
 - CI/script changes: none.
-- Docs changes: record `CTX-010` consumer migration scope and verification.
+- Docs changes: record `CTX-011` compatibility fallback cleanup scope and
+  verification.
 
 ## Phase 0 Tasks
 
@@ -232,6 +231,19 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
     usage cache persistence, and existing storage error paths.
   - Verification: formatting, compile checks, migration guards, diff hygiene,
     Rust risk scan, and full `make pre-commit`.
+- [x] `CTX-011` Consolidate app usecase object-store fallback.
+  - Do: migrate app admin, bucket, multipart, and object usecases away from
+    direct `new_object_layer_fn` calls and through an explicit-context resolver
+    helper.
+  - Acceptance: usecase lookups keep their injected AppContext precedence,
+    preserve `without_context()` legacy global object-layer fallback semantics,
+    and avoid consulting the global AppContext when a usecase intentionally has
+    no context.
+  - Must preserve: admin storage/data-usage reads, bucket create/delete/list
+    behavior, multipart object writes, object API reads/writes, lifecycle
+    transition tests, and existing "Not init" error paths.
+  - Verification: formatting, compile checks, migration guards, diff hygiene,
+    Rust risk scan, and full `make pre-commit`.
 
 ## Phase 1 Security Governance Tasks
 
@@ -538,8 +550,8 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 
 ## Next PRs
 
-1. `consumer-migration`: review app compatibility fallback call sites before
-   the final global-accessor cleanup phase.
+1. `consumer-migration`: remove the final old global object-layer accessor
+   compatibility path once downstream/public API cleanup is accepted.
 2. `pure-move`: start `R-009` boot wrapper with the IAM degraded readiness
    contract covered.
 
@@ -547,13 +559,13 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 
 | Expert | Status | Notes |
 |---|---|---|
-| Quality/architecture | passed | Single consumer-migration slice; ECStore internal/background consumers use the ECStore-owned resolver without adding application-layer dependencies or changing the fallback definition. |
-| Migration preservation | passed | Metrics, notification, tier, decommission, admin info, bucket metadata, replication, lifecycle, and data-usage call sites keep the same missing-store/error behavior while preferring the AppContext-owned store when installed. |
-| Testing/verification | passed | Formatting, compile checks, diff hygiene, migration/layer guards, Rust risk scan, branch freshness check, and full `make pre-commit` passed. |
+| Quality/architecture | passed | Single consumer-migration slice; app usecases delegate object-store fallback to the AppContext compatibility helper instead of duplicating direct global accessor calls. |
+| Migration preservation | passed | Admin, bucket, multipart, and object usecases keep injected context precedence and explicit no-context legacy global fallback behavior. |
+| Testing/verification | passed | Formatting, compile checks, migration/layer guards, Rust risk scan, branch freshness check, and full `make pre-commit` passed. |
 
 ## Verification Notes
 
-Passed on `8f6b1d47b5af689e0b3576ab4448cc4274786df1`:
+Passed on `fc894c9b569229101f859a6c4097eb64d3f86f5c`:
 
 - `cargo fmt --all --check`.
 - `cargo check -p rustfs-ecstore`.
@@ -563,26 +575,21 @@ Passed on `8f6b1d47b5af689e0b3576ab4448cc4274786df1`:
 - `./scripts/check_layer_dependencies.sh`.
 - `git rev-list --left-right --count HEAD...origin/main` returned `1 0`
   after rebase.
-- Rust risk scan for changed Rust files; full-file matches were existing tests,
-  existing relaxed counters, existing numeric casts, existing print/debug
-  helpers, and existing unwrap/expect paths, and the added-line scan returned
-  no `unwrap`/`expect`, numeric cast, string error, boxed error, print macro, or
-  relaxed-ordering match.
-- `make pre-commit`; all checks passed, including nextest 5954 passed and 111
-  skipped, plus doctests.
+- Rust risk scan for changed Rust files: full-file matches were existing tests,
+  existing numeric casts, existing string error signatures, and existing relaxed
+  counters; added-line scan returned no unwrap/expect, numeric cast, string
+  error, boxed error, print macro, or relaxed-ordering match.
+- `make pre-commit`: all checks passed, including nextest with 5961 passed
+  and 111 skipped, plus doctests.
 
 Notes:
 
-- This slice migrates ECStore internal/background object-store lookups to the
-  ECStore-owned resolver.
-- App compatibility fallback call sites remain on `new_object_layer_fn` as an
-  explicit fallback path.
+- This slice consolidates app usecase object-store fallback without changing
+  request behavior.
 - The old global accessor remains as the resolver fallback and public
   compatibility re-export for a later cleanup slice.
 
 ## Handoff Notes
 
-- CTX-010 is complete.
-- App compatibility fallback call sites remain on `new_object_layer_fn` as an
-  explicit fallback path.
+- CTX-011 is complete.
 - The global fallback definition and re-export remain for a later cleanup slice.

rustfs/src/app/admin_usecase.rs

@@ -14,7 +14,7 @@
 
 //! Admin application use-case contracts.
 
-use crate::app::context::{AppContext, get_global_app_context};
+use crate::app::context::{AppContext, get_global_app_context, resolve_object_store_handle_for_context};
 use crate::capacity::resolve_admin_used_capacity;
 use crate::error::ApiError;
 use crate::server::{DependencyReadiness, collect_dependency_readiness as collect_runtime_dependency_readiness};
@@ -22,7 +22,6 @@ use rustfs_data_usage::DataUsageInfo;
 use rustfs_ecstore::admin_server_info::get_server_info;
 use rustfs_ecstore::data_usage::{apply_bucket_usage_memory_overlay, load_data_usage_from_backend};
 use rustfs_ecstore::endpoints::EndpointServerPools;
-use rustfs_ecstore::new_object_layer_fn;
 use rustfs_ecstore::pools::{PoolDecommissionInfo, PoolStatus, get_total_usable_capacity, get_total_usable_capacity_free};
 use rustfs_ecstore::store::ECStore;
 use rustfs_madmin::{InfoMessage, StorageInfo};
@@ -104,10 +103,7 @@ impl DefaultAdminUsecase {
     }
 
     fn object_store(&self) -> Option<Arc<ECStore>> {
-        self.context
-            .as_ref()
-            .map(|context| context.object_store())
-            .or_else(new_object_layer_fn)
+        resolve_object_store_handle_for_context(self.context.as_deref())
     }
 
     fn app_error(code: S3ErrorCode, message: impl Into<String>) -> ApiError {

rustfs/src/app/bucket_usecase.rs

@@ -17,7 +17,9 @@
 use crate::admin::handlers::site_replication::{
     site_replication_bucket_meta_hook, site_replication_delete_bucket_hook, site_replication_make_bucket_hook,
 };
-use crate::app::context::{AppContext, default_notify_interface, get_global_app_context};
+use crate::app::context::{
+    AppContext, default_notify_interface, get_global_app_context, resolve_object_store_handle_for_context,
+};
 use crate::auth::get_condition_values_with_client_info;
 use crate::error::ApiError;
 use crate::server::RemoteAddr;
@@ -53,7 +55,6 @@ use rustfs_ecstore::bucket::{
 };
 use rustfs_ecstore::client::object_api_utils::to_s3s_etag;
 use rustfs_ecstore::error::StorageError;
-use rustfs_ecstore::new_object_layer_fn;
 use rustfs_ecstore::notification_sys::get_global_notification_sys;
 use rustfs_ecstore::store::ECStore;
 use rustfs_ecstore::store_api::{BucketOperations, ListObjectVersionsInfo, ListObjectsV2Info, ListOperations, ObjectInfo};
@@ -740,10 +741,7 @@ impl DefaultBucketUsecase {
     }
 
     fn object_store(&self) -> Option<Arc<ECStore>> {
-        self.context
-            .as_ref()
-            .map(|context| context.object_store())
-            .or_else(new_object_layer_fn)
+        resolve_object_store_handle_for_context(self.context.as_deref())
     }
 
     #[instrument(

rustfs/src/app/context/compat.rs

@@ -41,7 +41,13 @@ pub fn resolve_bucket_metadata_handle() -> Option<Arc<RwLock<BucketMetadataSys>>
 
 /// Resolve object store handle using AppContext-first precedence.
 pub fn resolve_object_store_handle() -> Option<Arc<ECStore>> {
-    resolve_object_store_handle_with(get_global_app_context(), new_object_layer_fn)
+    let context = get_global_app_context();
+    resolve_object_store_handle_for_context(context.as_deref())
+}
+
+/// Resolve object store handle using an explicit AppContext, falling back to the legacy global object layer.
+pub fn resolve_object_store_handle_for_context(context: Option<&AppContext>) -> Option<Arc<ECStore>> {
+    context.map(|context| context.object_store()).or_else(new_object_layer_fn)
 }
 
 /// Resolve endpoints using AppContext-first precedence.
@@ -77,6 +83,7 @@ fn resolve_bucket_metadata_handle_with(
         .or_else(fallback)
 }
 
+#[cfg(test)]
 fn resolve_object_store_handle_with(
     context: Option<Arc<AppContext>>,
     fallback: impl FnOnce() -> Option<Arc<ECStore>>,

rustfs/src/app/multipart_usecase.rs

@@ -14,7 +14,7 @@
 
 //! Multipart application use-case contracts.
 
-use crate::app::context::{AppContext, get_global_app_context};
+use crate::app::context::{AppContext, get_global_app_context, resolve_object_store_handle_for_context};
 use crate::app::object_usecase::{build_put_like_object_lock_metadata, validate_existing_object_lock_for_write};
 use crate::capacity::record_capacity_write;
 use crate::error::ApiError;
@@ -48,7 +48,6 @@ use rustfs_ecstore::bucket::{
 use rustfs_ecstore::client::object_api_utils::to_s3s_etag;
 use rustfs_ecstore::compress::is_disk_compressible;
 use rustfs_ecstore::error::{StorageError, is_err_object_not_found, is_err_version_not_found};
-use rustfs_ecstore::new_object_layer_fn;
 #[cfg(test)]
 use rustfs_ecstore::rio::{DecryptReader, EncryptReader, HardLimitReader, boxed_reader, wrap_reader};
 use rustfs_ecstore::rio::{HashReader, WritePlan};
@@ -230,10 +229,7 @@ impl DefaultMultipartUsecase {
     }
 
     fn object_store(&self) -> Option<Arc<ECStore>> {
-        self.context
-            .as_ref()
-            .map(|context| context.object_store())
-            .or_else(new_object_layer_fn)
+        resolve_object_store_handle_for_context(self.context.as_deref())
     }
 
     #[instrument(level = "debug", skip(self))]

rustfs/src/app/object_usecase.rs

@@ -14,7 +14,9 @@
 
 //! Object application use-case contracts.
 
-use crate::app::context::{AppContext, default_notify_interface, get_global_app_context};
+use crate::app::context::{
+    AppContext, default_notify_interface, get_global_app_context, resolve_object_store_handle_for_context,
+};
 use crate::config::RustFSBufferConfig;
 use crate::delete_tail_activity::{DeleteTailActivityGuard, DeleteTailStage};
 use crate::error::ApiError;
@@ -73,7 +75,6 @@ use rustfs_ecstore::compress::{MIN_DISK_COMPRESSIBLE_SIZE, is_disk_compressible}
 use rustfs_ecstore::config::storageclass;
 use rustfs_ecstore::disk::{error::DiskError, error_reduce::is_all_buckets_not_found};
 use rustfs_ecstore::error::{StorageError, is_err_bucket_not_found, is_err_object_not_found, is_err_version_not_found};
-use rustfs_ecstore::new_object_layer_fn;
 use rustfs_ecstore::rio::{DynReader, HashReader, WritePlan, wrap_reader};
 use rustfs_ecstore::set_disk::{get_lock_acquire_timeout, is_valid_storage_class};
 use rustfs_ecstore::store::ECStore;
@@ -1158,10 +1159,7 @@ impl DefaultObjectUsecase {
     }
 
     fn object_store(&self) -> Option<Arc<ECStore>> {
-        self.context
-            .as_ref()
-            .map(|context| context.object_store())
-            .or_else(new_object_layer_fn)
+        resolve_object_store_handle_for_context(self.context.as_deref())
     }
 
     fn base_buffer_size(&self) -> usize {