fix(tsp-js): raise MAX_HOPS to 64 so longer routes interoperate

packages/tsp-js/CHANGELOG.md

@@ -17,6 +17,9 @@ For history before this file, see `git log` on `packages/tsp-js`.
 
 ### Fixed
 
+- `MAX_HOPS` is 64 (was 10). The specification sets no maximum, and 12-hop
+  routes packed by every other implementation were refused on decode. The same
+  bound applies when packing a route and when decoding a hop list or reply path.
 - An XSCS/XCTL body that is not exactly one Bytes primitive is refused. It was
   read as its first primitive, silently dropping the rest of the `-A##` stream,
   and data after the stream was ignored. See

packages/tsp-js/src/cesr/wire.ts

@@ -388,8 +388,11 @@ export function decodeVariableData(
   return stream.slice(range.begin, range.end);
 }
 
-/** Max hops accepted in a routed message's hop list (bounds a hostile count). */
-export const MAX_HOPS = 10;
+/** Max hops accepted in a routed message's hop list or reply path (bounds a
+ *  hostile count). The spec sets no maximum, so this is a local choice that
+ *  caps interoperability: 64 matches the other affinidi TSP implementations.
+ *  It was 10, which refused 12-hop routes every other implementation opens. */
+export const MAX_HOPS = 64;
 
 /** Read the `YTSP` genus marker and its version count code. Advances `cur`.
  *

packages/tsp-js/tests/message.routed.mjs

@@ -48,6 +48,17 @@ test("packRouted rejects empty and over-long routes", async () => {
   await assert.rejects(packRouted(enc.encode("x"), tooMany, alice.vid, hop1.vid, packKeys(alice, hop1)));
 });
 
+test("a route at MAX_HOPS packs and opens with its hops intact", async () => {
+  // 12 hops was refused when the limit was 10.
+  const alice = party("did:web:alice");
+  const hop1 = party("did:web:hop1");
+  const route = Array.from({ length: MAX_HOPS }, (_, i) => `did:web:h${i}`);
+  const packed = await packRouted(enc.encode("abc"), route, alice.vid, hop1.vid, packKeys(alice, hop1));
+  const opened = await unpack(packed.bytes, unpackKeys(hop1, alice));
+  assert.equal(opened.messageType, "routed");
+  assert.deepEqual(opened.hops, route);
+});
+
 test("routed multi-hop round-trip: alice → hop1 → hop2 → final (inner opaque)", async () => {
   const alice = party("did:web:alice");
   const hop1 = party("did:web:hop1");