Preserve maintenance timeout behavior and prepare SILO 20261026

Signed-off-by: Feng Ruohang <rh@vonng.com>

cmd/object-mutation-helpers-strict_test.go

@@ -0,0 +1,57 @@
+//go:build consistency_strict
+
+// Copyright (c) 2026 Feng Ruohang
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+package cmd
+
+import (
+	"bytes"
+	"maps"
+)
+
+// Compare logical version state, excluding per-shard checksums/index, physical
+// DataDir placement and properties of other versions in the same xl.meta.
+// Different DataDir values remain readable for the existing rebalance recovery
+// contract; rollback separately requires an exact DataDir match.
+func sameFileInfoVersion(a, b FileInfo) bool {
+	if a.VersionID != b.VersionID || a.Deleted != b.Deleted || a.XLV1 != b.XLV1 || a.Size != b.Size ||
+		a.TransitionStatus != b.TransitionStatus || a.TransitionTier != b.TransitionTier ||
+		a.TransitionedObjName != b.TransitionedObjName || a.TransitionVersionID != b.TransitionVersionID ||
+		!sameVersionMetadata(a.Metadata, b.Metadata) || !bytes.Equal(a.Checksum, b.Checksum) || len(a.Parts) != len(b.Parts) {
+		return false
+	}
+	if !a.Deleted && a.Size != 0 && !a.Erasure.Equal(b.Erasure) {
+		return false
+	}
+	for i, p := range a.Parts {
+		q := b.Parts[i]
+		if p.Number != q.Number || p.Size != q.Size || p.ActualSize != q.ActualSize || p.ETag != q.ETag || !bytes.Equal(p.Index, q.Index) {
+			return false
+		}
+	}
+	return true
+}
+
+// The undo capability controls rollback ownership, not the logical contents.
+// A partial no-op update can revoke it without changing a single public field.
+func sameVersionMetadata(a, b map[string]string) bool {
+	if a[rollbackIDKey] == b[rollbackIDKey] {
+		return maps.Equal(a, b)
+	}
+	for k, v := range a {
+		if k != rollbackIDKey {
+			if other, ok := b[k]; !ok || other != v {
+				return false
+			}
+		}
+	}
+	for k := range b {
+		if k != rollbackIDKey {
+			if _, ok := a[k]; !ok {
+				return false
+			}
+		}
+	}
+	return true
+}