Address review comments from @henrymercer

lib/trap-caching.js

@@ -32,11 +32,13 @@ const util_1 = require("./util");
 // this for CLI/extractor changes, since the CLI version also
 // goes into the cache key.
 const CACHE_VERSION = 1;
+// This constant sets the size of each TRAP cache in megabytes.
+const CACHE_SIZE_MB = 1024;
 async function getTrapCachingExtractorConfigArgs(config) {
     const result = [];
     for (const language of config.languages)
-        result.push(...(await getTrapCachingExtractorConfigArgsForLang(config, language)));
-    return result;
+        result.push(await getTrapCachingExtractorConfigArgsForLang(config, language));
+    return result.flat();
 }
 exports.getTrapCachingExtractorConfigArgs = getTrapCachingExtractorConfigArgs;
 async function getTrapCachingExtractorConfigArgsForLang(config, language) {
@@ -46,11 +48,19 @@ async function getTrapCachingExtractorConfigArgsForLang(config, language) {
     const write = await actionsUtil.isAnalyzingDefaultBranch();
     return [
         `-O=${language}.trap.cache.dir=${cacheDir}`,
-        `-O=${language}.trap.cache.bound=1024`,
+        `-O=${language}.trap.cache.bound=${CACHE_SIZE_MB}`,
         `-O=${language}.trap.cache.write=${write}`,
     ];
 }
 exports.getTrapCachingExtractorConfigArgsForLang = getTrapCachingExtractorConfigArgsForLang;
+/**
+ * Download TRAP caches from the Actions cache.
+ * @param codeql The CodeQL instance to use.
+ * @param languages The languages being analyzed.
+ * @param logger A logger to record some informational messages to.
+ * @returns A partial map from languages to TRAP cache paths on disk, with
+ * languages for which we shouldn't use TRAP caching omitted.
+ */
 async function downloadTrapCaches(codeql, languages, logger) {
     var _a, _b;
     const result = {};
@@ -70,22 +80,25 @@ async function downloadTrapCaches(codeql, languages, logger) {
     }
     let baseSha = "unknown";
     const eventPath = process.env.GITHUB_EVENT_PATH;
-    if (eventPath !== undefined) {
+    if (process.env.GITHUB_EVENT_NAME === "pull_request" &&
+        eventPath !== undefined) {
         const event = JSON.parse(fs.readFileSync(path.resolve(eventPath), "utf-8"));
-        baseSha = ((_b = (_a = event.pull_request) === null || _a === void 0 ? void 0 : _a.base) === null || _b === void 0 ? void 0 : _b.sha) || "unknown";
+        baseSha = ((_b = (_a = event.pull_request) === null || _a === void 0 ? void 0 : _a.base) === null || _b === void 0 ? void 0 : _b.sha) || baseSha;
     }
     for (const language of languages) {
         const cacheDir = result[language];
         if (cacheDir === undefined)
             continue;
         // The SHA from the base of the PR is the most similar commit we might have a cache for
-        const preferredKey = `codeql-trap-${CACHE_VERSION}-${await codeql.getVersion()}-${language}-${baseSha}`;
+        const preferredKey = await cacheKey(codeql, language, baseSha);
         logger.info(`Looking in Actions cache for TRAP cache with key ${preferredKey}`);
         const found = await cache.restoreCache([cacheDir], preferredKey, [
-            `codeql-trap-${CACHE_VERSION}-${await codeql.getVersion()}-${language}-`, // Fall back to any cache with the right key prefix
+            await cachePrefix(codeql, language), // Fall back to any cache with the right key prefix
         ]);
         if (found === undefined) {
-            // Didn't find any cache, let's unset to avoid lookups in an empty directory
+            // We didn't find a TRAP cache in the Actions cache, so the directory on disk is
+            // still just an empty directory. There's no reason to tell the extractor to use it,
+            // so let's unset the entry in the map so we don't set any extractor options.
             logger.info(`No TRAP cache found in Actions cache for ${language}`);
             result[language] = undefined;
         }
@@ -96,14 +109,16 @@ exports.downloadTrapCaches = downloadTrapCaches;
 async function uploadTrapCaches(codeql, config, logger) {
     if (!(await actionsUtil.isAnalyzingDefaultBranch()))
         return; // Only upload caches from the default branch
+    const toAwait = [];
     for (const language of config.languages) {
         const cacheDir = config.trapCaches[language];
         if (cacheDir === undefined)
             continue;
-        const key = `codeql-trap-${CACHE_VERSION}-${await codeql.getVersion()}-${language}-${process.env.GITHUB_SHA || "unknown"}`;
+        const key = await cacheKey(codeql, language, process.env.GITHUB_SHA || "unknown");
         logger.info(`Uploading TRAP cache to Actions cache with key ${key}`);
-        await cache.saveCache([cacheDir], key);
+        toAwait.push(cache.saveCache([cacheDir], key));
     }
+    await Promise.all(toAwait);
 }
 exports.uploadTrapCaches = uploadTrapCaches;
 async function getLanguagesSupportingCaching(codeql, languages, logger) {
@@ -113,6 +128,8 @@ async function getLanguagesSupportingCaching(codeql, languages, logger) {
         return result;
     const resolveResult = await codeql.betterResolveLanguages();
     outer: for (const lang of languages) {
+        if (resolveResult.extractors[lang].length !== 1)
+            continue;
         const extractor = resolveResult.extractors[lang][0];
         const trapCacheOptions = (_d = (_c = (_b = (_a = extractor.extractor_options) === null || _a === void 0 ? void 0 : _a.trap) === null || _b === void 0 ? void 0 : _b.properties) === null || _c === void 0 ? void 0 : _c.cache) === null || _d === void 0 ? void 0 : _d.properties;
         if (trapCacheOptions === undefined) {
@@ -130,4 +147,10 @@ async function getLanguagesSupportingCaching(codeql, languages, logger) {
     return result;
 }
 exports.getLanguagesSupportingCaching = getLanguagesSupportingCaching;
+async function cacheKey(codeql, language, baseSha) {
+    return `${await cachePrefix(codeql, language)}-${baseSha}`;
+}
+async function cachePrefix(codeql, language) {
+    return `codeql-trap-${CACHE_VERSION}-${await codeql.getVersion()}-${language}-`;
+}
 //# sourceMappingURL=trap-caching.js.map