core/rawdb: fix underflow in freezer inspect for empty ancients

[VolodymyrBg]

fixed an underflow in core/rawdb/ancient_utils.go where inspect() assigned info.head = ancients - 1 unconditionally, which produced ^uint64(0) when Ancients() == 0. Although freezerInfo.count() previously happened to return 0 in the empty case due to unsigned wraparound and the invariant that Tail() == 0 for an empty freezer, the code was fragile and left head invalid. The fix adds an explicit ancients field to freezerInfo, computes the count as ancients - tail with a guard for ancients <= tail, and only sets head when ancients > 0. This aligns the implementation with the ethdb interface contract (see ethdb/database.go for Ancients() and Tail() semantics) and preserves behavior for non-empty freezers while removing reliance on overflow behavior. The changes are localized to core/rawdb/ancient_utils.go (freezerInfo, count(), and inspect()), and callers such as InspectDatabase in core/rawdb/database.go continue to function the same, now with explicit and safe arithmetic.

[rjl493456442]

good catch, how about this?

diff --git a/core/rawdb/ancient_utils.go b/core/rawdb/ancient_utils.go
index b940d91040..ccaa9776be 100644
--- a/core/rawdb/ancient_utils.go
+++ b/core/rawdb/ancient_utils.go
@@ -34,14 +34,10 @@ type freezerInfo struct {
 	name  string      // The identifier of freezer
 	head  uint64      // The number of last stored item in the freezer
 	tail  uint64      // The number of first stored item in the freezer
+	count uint64      // The number of stored items in the freezer
 	sizes []tableSize // The storage size per table
 }
 
-// count returns the number of stored items in the freezer.
-func (info *freezerInfo) count() uint64 {
-	return info.head - info.tail + 1
-}
-
 // size returns the storage size of the entire freezer.
 func (info *freezerInfo) size() common.StorageSize {
 	var total common.StorageSize
@@ -65,14 +61,23 @@ func inspect(name string, order map[string]freezerTableConfig, reader ethdb.Anci
 	if err != nil {
 		return freezerInfo{}, err
 	}
-	info.head = ancients - 1
-
+	if ancients == 0 {
+		info.head = 0
+	} else {
+		info.head = ancients - 1
+	}
 	// Retrieve the number of first stored item
 	tail, err := reader.Tail()
 	if err != nil {
 		return freezerInfo{}, err
 	}
 	info.tail = tail
+
+	if ancients == 0 {
+		info.count = 0
+	} else {
+		info.count = info.head - info.tail + 1
+	}
 	return info, nil
 }
 
diff --git a/core/rawdb/database.go b/core/rawdb/database.go
index d5c0f0aab2..448922d9bd 100644
--- a/core/rawdb/database.go
+++ b/core/rawdb/database.go
@@ -644,7 +644,7 @@ func InspectDatabase(db ethdb.Database, keyPrefix, keyStart []byte) error {
 				fmt.Sprintf("Ancient store (%s)", strings.Title(ancient.name)),
 				strings.Title(table.name),
 				table.size.String(),
-				fmt.Sprintf("%d", ancient.count()),
+				fmt.Sprintf("%d", ancient.count),
 			})
 		}
 		total.Add(uint64(ancient.size()))

[VolodymyrBg]

good catch, how about this?

diff --git a/core/rawdb/ancient_utils.go b/core/rawdb/ancient_utils.go
index b940d91040..ccaa9776be 100644
--- a/core/rawdb/ancient_utils.go
+++ b/core/rawdb/ancient_utils.go
@@ -34,14 +34,10 @@ type freezerInfo struct {
 	name  string      // The identifier of freezer
 	head  uint64      // The number of last stored item in the freezer
 	tail  uint64      // The number of first stored item in the freezer
+	count uint64      // The number of stored items in the freezer
 	sizes []tableSize // The storage size per table
 }
 
-// count returns the number of stored items in the freezer.
-func (info *freezerInfo) count() uint64 {
-	return info.head - info.tail + 1
-}
-
 // size returns the storage size of the entire freezer.
 func (info *freezerInfo) size() common.StorageSize {
 	var total common.StorageSize
@@ -65,14 +61,23 @@ func inspect(name string, order map[string]freezerTableConfig, reader ethdb.Anci
 	if err != nil {
 		return freezerInfo{}, err
 	}
-	info.head = ancients - 1
-
+	if ancients == 0 {
+		info.head = 0
+	} else {
+		info.head = ancients - 1
+	}
 	// Retrieve the number of first stored item
 	tail, err := reader.Tail()
 	if err != nil {
 		return freezerInfo{}, err
 	}
 	info.tail = tail
+
+	if ancients == 0 {
+		info.count = 0
+	} else {
+		info.count = info.head - info.tail + 1
+	}
 	return info, nil
 }
 
diff --git a/core/rawdb/database.go b/core/rawdb/database.go
index d5c0f0aab2..448922d9bd 100644
--- a/core/rawdb/database.go
+++ b/core/rawdb/database.go
@@ -644,7 +644,7 @@ func InspectDatabase(db ethdb.Database, keyPrefix, keyStart []byte) error {
 				fmt.Sprintf("Ancient store (%s)", strings.Title(ancient.name)),
 				strings.Title(table.name),
 				table.size.String(),
-				fmt.Sprintf("%d", ancient.count()),
+				fmt.Sprintf("%d", ancient.count),
 			})
 		}
 		total.Add(uint64(ancient.size()))

Ok, implemented

[rjl493456442]

It's not needed, please remove it

[VolodymyrBg]

It's not needed, please remove it

corrected