Add method to Hash256 to display shortened hashes (#9118)

#6689


  Inspired by the initial implementation of #9108, credit to @chong-he.
This adds an extension trait to `Hash256` and add a `short` method to provide smaller formatted hashes for logging.


Co-Authored-By: Mac L <mjladson@pm.me>

consensus/types/src/core/execution_block_hash.rs

@@ -5,7 +5,10 @@ use rand::RngCore;
 use serde::{Deserialize, Serialize};
 use ssz::{Decode, DecodeError, Encode};
 
-use crate::{core::Hash256, test_utils::TestRandom};
+use crate::{
+    core::{Hash256, Hash256Ext},
+    test_utils::TestRandom,
+};
 
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Default, Clone, Copy, Serialize, Deserialize, Eq, PartialEq, Hash)]
@@ -20,13 +23,7 @@ impl fmt::Debug for ExecutionBlockHash {
 
 impl fmt::Display for ExecutionBlockHash {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let hash = format!("{}", self.0);
-        write!(
-            f,
-            "{}…{}",
-            &hash[..6],
-            &hash[hash.len().saturating_sub(4)..]
-        )
+        self.0.short().fmt(f)
     }
 }
 

consensus/types/src/core/mod.rs

@@ -49,3 +49,29 @@ pub type Hash64 = alloy_primitives::B64;
 pub type Address = alloy_primitives::Address;
 pub type VersionedHash = Hash256;
 pub type MerkleProof = Vec<Hash256>;
+
+/// Extension trait for `Hash256` to allow us to implement additional methods on it.
+pub trait Hash256Ext {
+    fn short(&self) -> ShortenedHash<'_>;
+}
+
+impl Hash256Ext for Hash256 {
+    fn short(&self) -> ShortenedHash<'_> {
+        ShortenedHash(self)
+    }
+}
+
+pub struct ShortenedHash<'a>(&'a Hash256);
+
+impl<'a> std::fmt::Display for ShortenedHash<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let hash: &[u8; 32] = self.0.as_ref();
+        write!(
+            f,
+            // Format as hex, padded to 2 digits per byte.
+            // This outputs a consistent "0x1234...abcd" format.
+            "0x{:02x}{:02x}…{:02x}{:02x}",
+            hash[0], hash[1], hash[30], hash[31]
+        )
+    }
+}