From 9f0ea1cbf7406f28024053ce59137d588572f7a0 Mon Sep 17 00:00:00 2001
From: Fedor Indutny <79877362+indutny-signal@users.noreply.github.com>
Date: Fri, 21 Jan 2022 14:34:32 -0800
Subject: [PATCH] Use message.groupV2.revision during first fetch

---
 ts/groups.ts | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/ts/groups.ts b/ts/groups.ts
index 48a5897cf8..0c07114eca 100644
--- a/ts/groups.ts
+++ b/ts/groups.ts
@@ -2946,24 +2946,63 @@ async function getGroupUpdates({
         group,
         serverPublicParamsBase64,
         newRevision,
+
+        // If we just linked and this is a group where we have been a member
+        // from the beggining - applying all changes since the start is the best
+        // case scenario.
+        fallbackRevision: 0,
       });
 
       return result;
     } catch (error) {
+      const nextStep = isFirstFetch
+        ? `fetching logs since ${newRevision}`
+        : 'fetching full state';
+
       if (error.code === TEMPORAL_AUTH_REJECTED_CODE) {
         // We will fail over to the updateGroupViaState call below
         log.info(
-          `getGroupUpdates/${logId}: Temporal credential failure, now fetching full group state`
+          `getGroupUpdates/${logId}: Temporal credential failure, now ${nextStep}`
         );
       } else if (error.code === GROUP_ACCESS_DENIED_CODE) {
         // We will fail over to the updateGroupViaState call below
         log.info(
-          `getGroupUpdates/${logId}: Log access denied, now fetching full group state`
+          `getGroupUpdates/${logId}: Log access denied, now ${nextStep}`
         );
       } else {
         throw error;
       }
     }
+
+    // Fetch of logs starting from the revision 0 failed, so we probably were
+    // just invited to the group. Try fetching logs from the same revision as in
+    // this message.
+    if (isFirstFetch) {
+      try {
+        const result = await updateGroupViaLogs({
+          group,
+          serverPublicParamsBase64,
+          newRevision,
+          fallbackRevision: newRevision,
+        });
+
+        return result;
+      } catch (error) {
+        if (error.code === TEMPORAL_AUTH_REJECTED_CODE) {
+          // We will fail over to the updateGroupViaState call below
+          log.info(
+            `getGroupUpdates/${logId}: Temporal credential failure, now fetching full state`
+          );
+        } else if (error.code === GROUP_ACCESS_DENIED_CODE) {
+          // We will fail over to the updateGroupViaState call below
+          log.info(
+            `getGroupUpdates/${logId}: Log access denied, now fetching full state`
+          );
+        } else {
+          throw error;
+        }
+      }
+    }
   }
 
   if (window.GV2_ENABLE_STATE_PROCESSING) {
@@ -3081,9 +3120,11 @@ async function updateGroupViaSingleChange({
 async function updateGroupViaLogs({
   group,
   serverPublicParamsBase64,
+  fallbackRevision,
   newRevision,
 }: {
   group: ConversationAttributesType;
+  fallbackRevision: number;
   newRevision: number;
   serverPublicParamsBase64: string;
 }): Promise<UpdatesResultType> {
@@ -3096,6 +3137,7 @@ async function updateGroupViaLogs({
   const groupCredentials = getCredentialsForToday(data);
   const deltaOptions = {
     group,
+    fallbackRevision,
     newRevision,
     serverPublicParamsBase64,
     authCredentialBase64: groupCredentials.today.credential,
@@ -3219,11 +3261,13 @@ function getGroupCredentials({
 async function getGroupDelta({
   group,
   newRevision,
+  fallbackRevision,
   serverPublicParamsBase64,
   authCredentialBase64,
 }: {
   group: ConversationAttributesType;
   newRevision: number;
+  fallbackRevision: number;
   serverPublicParamsBase64: string;
   authCredentialBase64: string;
 }): Promise<UpdatesResultType> {
@@ -3246,7 +3290,9 @@ async function getGroupDelta({
   });
 
   const currentRevision = group.revision;
-  let revisionToFetch = isNumber(currentRevision) ? currentRevision + 1 : 0;
+  let revisionToFetch = isNumber(currentRevision)
+    ? currentRevision + 1
+    : fallbackRevision;
 
   let response;
   const changes: Array<Proto.IGroupChanges> = [];