fix(storage): custom impl of EnumCount for MerkleizedColumn

crates/storage/src/merkle/column.rs

@@ -19,7 +19,6 @@ use alloc::{
     Eq,
     Hash,
     enum_iterator::Sequence,
-    strum_macros::EnumCount,
     strum_macros::IntoStaticStr,
 )]
 pub enum MerkleizedColumn<TC> {
@@ -31,6 +30,16 @@ pub enum MerkleizedColumn<TC> {
     MerkleMetadataColumn,
 }
 
+impl<TC> strum::EnumCount for MerkleizedColumn<TC>
+where
+    TC: strum::EnumCount + AsU32,
+{
+    /// The total count of variants in the enum.
+    /// Since we have two columns for each table column and one for the merkle data,
+    /// we have to multiply the count of the table columns by 2 and add one for the merkle metadata.
+    const COUNT: usize = TC::COUNT * 2 + 1;
+}
+
 /// The trait to convert the column to the `u32`.
 pub trait AsU32 {
     /// Returns the `u32` representation of the `Column`.
@@ -42,21 +51,30 @@ where
     TC: strum::EnumCount + AsU32,
 {
     /// The total count of variants in the enum.
-    /// Since we have two columns for each table column and one for the merkle data,
-    /// we have to multiply the count of the table columns by 2 and add one for the merkle metadata.
-    pub const COUNT: usize = TC::COUNT * 2 + 1;
+    pub const COUNT: usize = <Self as strum::EnumCount>::COUNT;
 
     /// The start of the merkle data columns.
     pub const MERKLE_DATA_COLUMNS_START: u32 = u16::MAX as u32;
 
+    /// The merkle metadata column
+    pub const MERKLE_METADATA_COLUMN: u32 = {
+        assert!(Self::COUNT <= u32::MAX as usize);
+        // this is fine, because we already performed an assertion above
+        // see https://github.com/rust-lang/rust-clippy/issues/9613
+        #[allow(clippy::cast_possible_truncation)]
+        let column_index = (Self::COUNT as u32).saturating_sub(1);
+        assert!(column_index > 0);
+        column_index
+    };
+
     /// Returns the `u32` representation of the `Column`.
     pub fn as_u32(&self) -> u32 {
         match self {
             Self::TableColumn(column) => column.as_u32(),
             Self::MerkleDataColumn(column) => {
                 Self::MERKLE_DATA_COLUMNS_START.wrapping_add(column.as_u32())
             }
-            Self::MerkleMetadataColumn => u32::MAX,
+            Self::MerkleMetadataColumn => Self::MERKLE_METADATA_COLUMN,
         }
     }
 }