Further update to reflect a conversation with @henrymercer

src/trap-caching.ts

@@ -113,15 +113,15 @@ export async function downloadTrapCaches(
     logger.info(
       `Looking in Actions cache for TRAP cache with key ${preferredKey}`
     );
-    const found = await withTimeout(
-      MAX_CACHE_OPERATION_MS,
-      cache.restoreCache([cacheDir], preferredKey, [
-        await cachePrefix(codeql, language), // Fall back to any cache with the right key prefix
-      ]),
-      () => {
-        logger.info(
-          `Timed out waiting for TRAP cache download for ${language}, will continue without it`
-        );
+    const found = await cache.restoreCache(
+      [cacheDir],
+      preferredKey,
+      [
+        // Fall back to any cache with the right key prefix
+        await cachePrefix(codeql, language),
+      ],
+      {
+        segmentTimeoutInMs: MAX_CACHE_OPERATION_MS,
       }
     );
     if (found === undefined) {

src/util.ts

@@ -899,6 +899,9 @@ export async function tryGetFolderBytes(
  * Run a promise for a given amount of time, and if it doesn't resolve within
  * that time, call the provided callback and then return undefined.
  *
+ * Note that this does NOT cancel the original promise, so that promise will
+ * continue in the background even after the timeout has expired.
+ *
  * @param timeoutMs The timeout in milliseconds.
  * @param promise The promise to run.
  * @param onTimeout A callback to call if the promise times out.