Further update to reflect a conversation with @henrymercer

lib/trap-caching.js

@@ -100,10 +100,11 @@ async function downloadTrapCaches(codeql, languages, logger) {
         // The SHA from the base of the PR is the most similar commit we might have a cache for
         const preferredKey = await cacheKey(codeql, language, baseSha);
         logger.info(`Looking in Actions cache for TRAP cache with key ${preferredKey}`);
-        const found = await (0, util_1.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) {
             // We didn't find a TRAP cache in the Actions cache, so the directory on disk is

lib/util.js

@@ -748,6 +748,9 @@ exports.tryGetFolderBytes = 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.