overleaf/server-ce/hotfix/4.1.5/pr_15445.patch

--- services/history-v1/storage/lib/history_store.js
+++ services/history-v1/storage/lib/history_store.js
@@ -103,11 +103,11 @@ HistoryStore.prototype.storeRaw = function historyStoreStoreRaw(
   assert.object(rawHistory, 'bad rawHistory')

   const key = getKey(projectId, chunkId)
-  const stream = streams.gzipStringToStream(JSON.stringify(rawHistory))

   logger.debug({ projectId, chunkId }, 'storeRaw started')
   return BPromise.resolve()
-    .then(() =>
+    .then(() => streams.gzipStringToStream(JSON.stringify(rawHistory)))
+    .then(stream =>
       persistor.sendStream(BUCKET, key, stream, {
         contentType: 'application/json',
         contentEncoding: 'gzip',
--- services/history-v1/storage/lib/streams.js
+++ services/history-v1/storage/lib/streams.js
@@ -79,8 +79,15 @@ function gunzipStreamToBuffer(readStream) {
 exports.gunzipStreamToBuffer = gunzipStreamToBuffer

 function gzipStringToStream(string) {
-  const gzip = zlib.createGzip()
-  return new ReadableString(string).pipe(gzip)
+  return new BPromise(function (resolve, reject) {
+    zlib.gzip(Buffer.from(string), function (error, result) {
+      if (error) {
+        reject(error)
+      } else {
+        resolve(new ReadableString(result))
+      }
+    })
+  })
 }

 /**
@@ -88,6 +95,6 @@ function gzipStringToStream(string) {
  *
  * @function
  * @param {string} string
- * @return {stream.Writable}
+ * @return {Promise.<stream.Readable>}
  */
 exports.gzipStringToStream = gzipStringToStream