Fix deleted pad restored corrupted from cache

lib/hk-util.js

@@ -661,6 +661,8 @@ const handleGetHistory = function (Env, Server, seq, userId, parsed) {
             if (txid) { msg[0] = txid; }
             Server.send(userId, [0, HISTORY_KEEPER_ID, 'MSG', userId, JSON.stringify(msg)], readMore);
         }, (err) => {
+            // Any error but ENOENT: abort
+            // ENOENT is allowed in case we want to create a new pad
             if (err && err.code !== 'ENOENT') {
                 if (err.message === "EUNKNOWN") {
                     Log.error("HK_GET_HISTORY", {
@@ -680,6 +682,14 @@ const handleGetHistory = function (Env, Server, seq, userId, parsed) {
                 return;
             }
 
+            // If we're asking for a specific version (lastKnownHash) but we receive an
+            // ENOENT, this is not a pad creation so we need to abort.
+            if (err && err.code === 'ENOENT' && lastKnownHash) {
+                const parsedMsg2 = {error:'EDELETED', channel: channelName, txid: txid};
+                Server.send(userId, [0, HISTORY_KEEPER_ID, 'MSG', userId, JSON.stringify(parsedMsg2)]);
+                return;
+            }
+
             if (msgCount === 0 && !metadata_cache[channelName] && Server.channelContainsUser(channelName, userId)) {
                 handleFirstMessage(Env, channelName, metadata);
                 Server.send(userId, [0, HISTORY_KEEPER_ID, 'MSG', userId, JSON.stringify(metadata)]);