rewriteUrl can return a local path that can't be used by the URL Constructor

[wwahammy]

I'm trying to use web-archive-site-mirror at the page https://lcc-archive.aws.walkerart.org/collections/publications/jazz/creative-black-music-at-the-walker-selections-from-the-archives/. I'm getting a type error in the URL constructor called in initAnchorElemOverride: TypeError: URL constructor: /collections/publications/jazz/creative-black-music-foreword is not a valid URL.

The compiled but unminified code reads as follows

initAnchorElemOverride() {
        const t = Object.getOwnPropertyDescriptor(HTMLAnchorElement.prototype, 'href');
        if (!t?.get) return;
        const e = this,
        r = t.get,
        i = t => {
          const i = Object.getOwnPropertyDescriptor(HTMLAnchorElement.prototype, t);
          if (!i?.set) return;
          const o = i.set;
          Object.defineProperty(
            HTMLAnchorElement.prototype,
            t,
            {
              set(r) {
                const i = new URL(e.rewriteUrl(r));
                return o.call(this, i[t])
              },
              get() {
                return new URL(e.unrewriteUrl(r.call(this))) [t]
              }
            }
          )
        };
        i('href'),
        i('hostname'),
        i('host'),
        i('protocol'),
        i('origin')
      }

The error is happening an the line const i = new URL(e.rewriteUrl(r)); If I work my way backwards, I think this corresponds to

wabac.js/src/rewrite/proxyinject.ts

Line 432 in 94a1411

const url = new URL(rw.rewriteUrl(v));

.

I don't understand the code well enough to know what rewriteUrl (or convUrl inside it) SHOULD be returning and why they're returning the wrong thing though 😄