api: better handling of helper errors to distinguish error codes

src/model/k2v/causality.rs

@@ -16,8 +16,6 @@ use serde::{Deserialize, Serialize};
 
 use garage_util::data::*;
 
-use crate::helper::error::{Error as HelperError, OkOrBadRequest};
-
 /// Node IDs used in K2V are u64 integers that are the abbreviation
 /// of full Garage node IDs which are 256-bit UUIDs.
 pub type K2VNodeId = u64;
@@ -99,10 +97,6 @@ impl CausalContext {
 		Some(ret)
 	}
 
-	pub fn parse_helper(s: &str) -> Result<Self, HelperError> {
-		Self::parse(s).ok_or_bad_request("Invalid causality token")
-	}
-
 	/// Check if this causal context contains newer items than another one
 	pub fn is_newer_than(&self, other: &Self) -> bool {
 		vclock_gt(&self.vector_clock, &other.vector_clock)