fix: authedFetch URL resolution breaks when DENO_DEPLOY_ENDPOINT contains a path

Author: uriva

auth.ts

@@ -303,7 +303,7 @@ export async function authedFetch(
     `token=${auth}; deno_auth_ghid=force`,
   );
 
-  const url = new URL(endpoint, context.endpoint);
+  const url = new URL(`${context.endpoint}/${endpoint}`);
 
   let fallbackBody: ReadableStream | undefined;
   if (init.body instanceof ReadableStream) {

tests/url_resolution.test.ts

@@ -0,0 +1,40 @@
+import { assertEquals } from "@std/assert";
+
+// Reproduces the URL resolution behavior in authedFetch.
+// Before the fix: new URL(endpoint, base) drops path segments from the base.
+// After the fix: string concatenation preserves the full base path.
+
+Deno.test("new URL() two-arg drops base path segments", () => {
+  // This is the OLD (broken) behavior that motivates the fix.
+  // When the endpoint is a proxy URL with a path, the path-based
+  // target host segment gets silently dropped.
+  const base = "https://proxy.example.com/target-host";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const broken = new URL(endpoint, base);
+  // new URL resolves relative to the parent of "target-host", losing it:
+  assertEquals(broken.pathname, "/api/diffsync/org/app/rev123");
+  // "target-host" is gone — the proxy can no longer route the request.
+});
+
+Deno.test("string concatenation preserves base path segments", () => {
+  // This is the FIXED behavior: concatenation keeps the full base path.
+  const base = "https://proxy.example.com/target-host";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const fixed = new URL(`${base}/${endpoint}`);
+  assertEquals(
+    fixed.pathname,
+    "/target-host/api/diffsync/org/app/rev123",
+  );
+});
+
+Deno.test("string concatenation works for standard endpoint too", () => {
+  // Ensure the fix doesn't regress the normal (non-proxy) case.
+  const base = "https://console.deno.com";
+  const endpoint = "api/diffsync/org/app/rev123";
+
+  const fixed = new URL(`${base}/${endpoint}`);
+  assertEquals(fixed.pathname, "/api/diffsync/org/app/rev123");
+  assertEquals(fixed.hostname, "console.deno.com");
+});

util.ts

@@ -23,7 +23,7 @@ export function error(
 ): never {
   console.error();
   console.error(`${red("✗")} An error occurred:`);
-  console.error(`  ${error.replaceAll("\n", "\n  ")}`);
+  console.error(`  ${String(error ?? "Unknown error").replaceAll("\n", "\n  ")}`);
   const trace = response?.headers.get("x-deno-trace-id");
   if (context.debug) {
     console.error(`  stack:\n${new Error().stack}`);