fix: return differentiated errors from InsertedGER::verify instead of bool

crates/aggchain-proof-core/src/bridge/inserted_ger.rs

@@ -2,6 +2,18 @@ use agglayer_primitives::Digest;
 use serde::{Deserialize, Serialize};
 use unified_bridge::{L1InfoTreeLeaf, MerkleProof};
 
+/// Errors that can occur during GER verification
+#[derive(Debug, thiserror::Error)]
+pub enum GerVerificationError {
+    /// The provided L1 info root does not match the proof root
+    #[error("L1 info root mismatch: expected {expected:?}, got {got:?}")]
+    L1InfoRootMismatch { expected: Digest, got: Digest },
+
+    /// The Merkle proof verification failed
+    #[error("Merkle proof verification failed for leaf hash {leaf_hash:?} at index {index}")]
+    MerkleProofVerificationFailed { leaf_hash: Digest, index: u32 },
+}
+
 /// Data to verify the legitimacy of one inserted GER.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct InsertedGER {
@@ -17,16 +29,25 @@ pub struct InsertedGER {
 
 impl InsertedGER {
     /// Verify the inclusion proof against one L1 info root.
-    pub fn verify(&self, l1_info_root: Digest) -> bool {
-        // TODO: return differentiated errors
+    pub fn verify(&self, l1_info_root: Digest) -> Result<(), GerVerificationError> {
         if l1_info_root != self.proof.root {
-            return false;
+            return Err(GerVerificationError::L1InfoRootMismatch {
+                expected: self.proof.root,
+                got: l1_info_root,
+            });
+        }
+
+        let leaf_hash = self.l1_info_tree_leaf.hash();
+        let index = self.l1_info_tree_leaf.l1_info_tree_index;
+
+        if !self.proof.verify(leaf_hash, index) {
+            return Err(GerVerificationError::MerkleProofVerificationFailed {
+                leaf_hash,
+                index,
+            });
         }
 
-        self.proof.verify(
-            self.l1_info_tree_leaf.hash(),
-            self.l1_info_tree_leaf.l1_info_tree_index,
-        )
+        Ok(())
     }
 
     /// Returns the inserted GER.

crates/aggchain-proof-core/src/bridge/mod.rs

@@ -384,7 +384,7 @@ impl BridgeConstraintsInput {
             .bridge_witness
             .inserted_gers
             .iter()
-            .find(|ger| !ger.verify(self.l1_info_root));
+            .find(|ger| ger.verify(self.l1_info_root).is_err());
 
         if let Some(wrong_ger) = maybe_wrong_inserted_ger {
             return Err(BridgeConstraintsError::InvalidMerklePathGERToL1Root {