fix(access): l-04 misleading documentations regarding default admin role

contracts/src/access/AccessControl.compact

@@ -37,11 +37,10 @@ pragma language_version >= 0.21.0;
  * {revokeRole} circuits. Each role has an associated admin role, and only
  * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
  *
- * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
+ * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE` (zero bytes), which means
  * that only accounts with this role will be able to grant or revoke other
  * roles. More complex role relationships can be created by using
- * {_setRoleAdmin}. To set a custom `DEFAULT_ADMIN_ROLE`, implement the `Initializable`
- * module and set `DEFAULT_ADMIN_ROLE` in the `initialize()` circuit.
+ * {_setRoleAdmin}.
  *
  * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
  * grant and revoke this role. Extra precautions should be taken to secure
@@ -93,7 +92,15 @@ module AccessControl {
    */
   export ledger _adminRoles: Map<Bytes<32>, Bytes<32>>;
 
-  export ledger DEFAULT_ADMIN_ROLE: Bytes<32>;
+  /**
+   * @description The default admin role for all roles. Only accounts with this role will be able
+   * to grant or revoke other roles unless custom admin roles are created via {_setRoleAdmin}.
+   *
+   * @return {Bytes<32>} - The default admin role identifier (zero bytes).
+   */
+  export pure circuit DEFAULT_ADMIN_ROLE(): Bytes<32> {
+    return default<Bytes<32>>;
+  }
 
   /**
    * @description Returns `true` if `account` has been granted `roleId`.
@@ -167,7 +174,7 @@ module AccessControl {
     if (_adminRoles.member(disclose(roleId))) {
       return _adminRoles.lookup(disclose(roleId));
     }
-    return default<Bytes<32>>;
+    return DEFAULT_ADMIN_ROLE();
   }
 
   /**

contracts/src/access/test/mocks/MockAccessControl.compact

@@ -6,7 +6,11 @@ import CompactStandardLibrary;
 
 import "../../AccessControl" prefix AccessControl_;
 
-export { ZswapCoinPublicKey, ContractAddress, Either, Maybe, AccessControl_DEFAULT_ADMIN_ROLE };
+export { ZswapCoinPublicKey, ContractAddress, Either, Maybe };
+
+export pure circuit DEFAULT_ADMIN_ROLE(): Bytes<32> {
+  return AccessControl_DEFAULT_ADMIN_ROLE();
+}
 
 export circuit hasRole(roleId: Bytes<32>, account: Either<ZswapCoinPublicKey, ContractAddress>): Boolean {
   return AccessControl_hasRole(roleId, account);