fix(ecstore): resolve erasure parity per pool (#4801) (#5015)

* fix(ecstore): add fallible erasure construction

(cherry picked from commit bd148b20f7)

* fix(ecstore): resolve storage parity per pool

(cherry picked from commit c05c2cb24b)

* fix(ecstore): keep carved per-pool parity core self-contained on main

Fixups so the cherry-picked fallible-erasure + per-pool-parity core builds standalone on current main without the excluded scope-creep commits:
- runtime/sources.rs: re-add backend_storage_class_parities (removed by the per-pool commit; its rebalance caller was updated in an unrelated reporting commit that was left out). Reimplemented over the snapshot API, behavior-identical.
- config/mod.rs: rename the storage-class publish test module (main independently added a mod tests, so the cherry-pick collided).
- rustfs storage_api.rs + startup_storage.rs: route the storage-class ENV consts through the startup storage facade and use a local const for the erasure-set-drive-count env name, satisfying the layer/facade guardrail (main's guardrail is stricter than when the core was authored).

* fix(ecstore): use struct-init in erasure test helper to satisfy clippy field_reassign_with_default

The cherry-picked fallible-erasure commit's `erasure_with_invalid_dimensions` test helper built `Erasure` via `default()` then reassigned fields, which trips `clippy::field_reassign_with_default` under `-D warnings` (only surfaced by `--all-targets`, which lints test code). #4977 fixed this in a later commit that was not part of the carved core. Use struct-init with `..Default::default()`, matching #4977's final form.

* fix(rustfs): gate the test-only storage-class ENV facade re-export behind cfg(test)

The ENV constants (INLINE_BLOCK_ENV/OPTIMIZE_ENV/RRS_ENV/STANDARD_ENV) re-exported through the startup storage facade are only consumed by a #[cfg(test)] test in startup_storage.rs, so in a non-test lib build the re-export is unused and trips -D unused-imports under clippy --all-targets. Gate it with #[cfg(test)], matching #4977's final form.

---------

Co-authored-by: cxymds <cxymds@gmail.com>

crates/ecstore/src/set_disk/ops/heal.rs

@@ -163,12 +163,13 @@ impl SetDisks {
 
                         let erasure = if !latest_meta.deleted && !latest_meta.is_remote() {
                             // Initialize erasure coding; use legacy mode for old-version files
-                            coding::Erasure::new_with_options(
+                            coding::Erasure::try_new_with_options(
                                 latest_meta.erasure.data_blocks,
                                 latest_meta.erasure.parity_blocks,
                                 latest_meta.erasure.block_size,
                                 latest_meta.uses_legacy_checksum,
                             )
+                            .map_err(DiskError::from)?
                         } else {
                             coding::Erasure::default()
                         };

crates/ecstore/src/set_disk/ops/multipart.rs

@@ -355,7 +355,8 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
         let tmp_part_path = Arc::new(format!("{tmp_part}/{part_suffix}"));
 
         let result: Result<PartInfo> = async {
-            let erasure = coding::Erasure::new(fi.erasure.data_blocks, fi.erasure.parity_blocks, fi.erasure.block_size);
+            let erasure = coding::Erasure::try_new(fi.erasure.data_blocks, fi.erasure.parity_blocks, fi.erasure.block_size)
+                .map_err(Error::from)?;
             let writer_setup_stage_start = rustfs_io_metrics::put_stage_metrics_enabled().then(Instant::now);
 
             let mut writers = Vec::with_capacity(shuffle_disks.len());

crates/ecstore/src/set_disk/ops/object.rs

@@ -25,6 +25,11 @@ use crate::bucket::lifecycle::tier_sweeper::delete_object_from_remote_tier_idemp
 use crate::disk::OldCurrentSize;
 use crate::object_api::{GetObjectBodySource, get_object_body_cache_hook_suppressed};
 
+fn erasure_from_file_info(fi: &FileInfo, uses_legacy: bool) -> Result<coding::Erasure> {
+    coding::Erasure::try_new_with_options(fi.erasure.data_blocks, fi.erasure.parity_blocks, fi.erasure.block_size, uses_legacy)
+        .map_err(Error::from)
+}
+
 /// Length of the full plaintext body when — and only when — this read's output
 /// is exactly the object's complete plaintext, so the app-layer body cache may
 /// serve it in place of the erasure read.
@@ -292,12 +297,7 @@ impl crate::storage_api_contracts::object::ObjectIO for SetDisks {
                 }
             }
 
-            let erasure = coding::Erasure::new_with_options(
-                fi.erasure.data_blocks,
-                fi.erasure.parity_blocks,
-                fi.erasure.block_size,
-                fi.uses_legacy_checksum,
-            );
+            let erasure = erasure_from_file_info(&fi, fi.uses_legacy_checksum)?;
             let read_length = erasure.shard_file_offset(0, object_size, object_size);
             let total_shards = data_shards + fi.erasure.parity_blocks;
             let (_disks, files) = Self::shuffle_disks_and_parts_metadata_by_index(&disks, &files, &fi);
@@ -761,7 +761,7 @@ impl SetDisks {
         let tmp_object = format!("{}/{}/part.1", tmp_dir, fi.data_dir.unwrap());
 
         let result: Result<(ObjectInfo, Option<OldCurrentSize>)> = async {
-            let erasure = coding::Erasure::new(fi.erasure.data_blocks, fi.erasure.parity_blocks, fi.erasure.block_size);
+            let erasure = erasure_from_file_info(&fi, false)?;
 
             let put_object_size = known_put_object_storage_size(data.size());
             let is_inline_buffer =
@@ -2886,6 +2886,30 @@ fn drop_failed_writer_disks<D, W>(disks: &mut [Option<D>], writers: &[Option<W>]
     committed
 }
 
+#[cfg(test)]
+mod erasure_construction_tests {
+    use super::*;
+    use crate::erasure::coding::ErasureConstructionError;
+    use std::error::Error as _;
+
+    #[test]
+    fn object_file_info_mapping_preserves_construction_error() {
+        let mut fi = FileInfo::new("object", 2, 2);
+        fi.erasure.block_size = 0;
+
+        let error = match erasure_from_file_info(&fi, false) {
+            Ok(_) => panic!("invalid object erasure metadata must be rejected"),
+            Err(error) => error,
+        };
+        assert!(error.to_string().contains("block_size must be greater than zero"));
+        let io_source = error.source().expect("StorageError::Io must expose its io::Error source");
+        let construction_source = io_source
+            .source()
+            .expect("io::Error must expose the erasure construction error");
+        assert!(construction_source.is::<ErasureConstructionError>());
+    }
+}
+
 #[cfg(test)]
 mod b3_write_quorum_tests {
     use super::drop_failed_writer_disks;