fix(cache): distinguish between null and undefined (#6509)

null = this lookup returned nothing last time
undefined = no cached result found

lib/manager/bazel/update.ts

@@ -51,7 +51,7 @@ async function getHashFromUrl(url: string): Promise<string | null> {
     url
   );
   /* istanbul ignore next line */
-  if (cachedResult) {
+  if (cachedResult !== undefined) {
     return cachedResult;
   }
   try {

lib/util/cache/global/file.spec.ts

@@ -6,8 +6,10 @@ describe('lib/util/cache/global/file', () => {
     init(os.tmpdir());
   });
 
-  it('gets null', async () => {
-    expect(await global.renovateCache.get('test', 'missing-key')).toBeNull();
+  it('returns undefined if no match', async () => {
+    expect(
+      await global.renovateCache.get('test', 'missing-key')
+    ).toBeUndefined();
   });
 
   it('sets and gets', async () => {
@@ -17,6 +19,6 @@ describe('lib/util/cache/global/file', () => {
 
   it('expires', async () => {
     await global.renovateCache.set('test', 'key', 1234, -5);
-    expect(await global.renovateCache.get('test', 'key')).toBeNull();
+    expect(await global.renovateCache.get('test', 'key')).toBeUndefined();
   });
 });

lib/util/cache/global/file.ts

@@ -29,7 +29,7 @@ async function get<T = never>(namespace: string, key: string): Promise<T> {
   } catch (err) {
     logger.trace({ namespace, key }, 'Cache miss');
   }
-  return null;
+  return undefined;
 }
 
 async function set(

lib/workers/pr/changelog/release-notes.ts

@@ -355,7 +355,7 @@ export async function addReleaseNotes(
     let releaseNotes: ChangeLogNotes;
     const cacheKey = getCacheKey(v.version);
     releaseNotes = await globalCache.get(cacheNamespace, cacheKey);
-    if (!releaseNotes) {
+    if (releaseNotes === undefined) {
       if (input.project.github != null) {
         releaseNotes = await getReleaseNotesMd(
           repository,
@@ -388,7 +388,7 @@ export async function addReleaseNotes(
       await globalCache.set(
         cacheNamespace,
         cacheKey,
-        releaseNotes,
+        releaseNotes || null,
         cacheMinutes
       );
     }

lib/workers/pr/changelog/source-github.ts

@@ -155,7 +155,7 @@ export async function getChangeLogJSON({
         getCacheKey(prev.version, next.version)
       );
       // istanbul ignore else
-      if (!release) {
+      if (release === undefined) {
         release = {
           version: next.version,
           date: next.releaseTimestamp,

lib/workers/pr/changelog/source-gitlab.ts

@@ -135,7 +135,7 @@ export async function getChangeLogJSON({
         cacheNamespace,
         getCacheKey(prev.version, next.version)
       );
-      if (!release) {
+      if (release === undefined) {
         release = {
           version: next.version,
           date: next.releaseTimestamp,

lib/workers/repository/stats.ts

@@ -26,7 +26,7 @@ export function printRequestStats(): void {
     requestHosts[hostname] = requestHosts[hostname] || [];
     requestHosts[hostname].push(request.duration);
   }
-  logger.trace({ allRequests, requestHosts }, 'full stats');
+  logger.debug({ allRequests, requestHosts }, 'full stats');
   const hostStats: string[] = [];
   let totalRequests = 0;
   for (const [hostname, requests] of Object.entries(requestHosts)) {