Add a debug log message when forcing the latest tools

lib/codeql.js

@@ -226,17 +226,22 @@ async function getCodeQLBundleDownloadURL(apiDetails, variant, logger) {
  */
 async function setupCodeQL(codeqlURL, apiDetails, tempDir, variant, featureFlags, logger, checkVersion) {
     try {
-        const forceLatest = 
+        const forceLatestReason = 
         // We use the special value of 'latest' to prioritize the version in the
         // defaults over any pinned cached version.
-        codeqlURL === "latest" ||
-            // If the user hasn't requested a particular CodeQL version, then bypass
-            // the toolcache when the appropriate feature flag is enabled. This
-            // allows us to quickly rollback a broken bundle that has made its way
-            // into the toolcache.
-            (codeqlURL === undefined &&
-                (await featureFlags.getValue(feature_flags_1.FeatureFlag.BypassToolcacheEnabled)));
+        codeqlURL === "latest"
+            ? '"tools: latest" was requested'
+            : // If the user hasn't requested a particular CodeQL version, then bypass
+                // the toolcache when the appropriate feature flag is enabled. This
+                // allows us to quickly rollback a broken bundle that has made its way
+                // into the toolcache.
+                codeqlURL === undefined &&
+                    (await featureFlags.getValue(feature_flags_1.FeatureFlag.BypassToolcacheEnabled))
+                    ? "a specific version of CodeQL was not requested, and the bypass toolcache feature flag is enabled"
+                    : undefined;
+        const forceLatest = forceLatestReason !== undefined;
         if (forceLatest) {
+            logger.debug(`Forcing the latest version of the CodeQL tools since ${forceLatestReason}.`);
             codeqlURL = undefined;
         }
         let codeqlFolder;