core: allow repeat connection via group link if group was deleted but contact with host is present (#1335)

src/Simplex/Chat/Store.hs

@@ -1736,8 +1736,24 @@ deleteGroupConnectionsAndFiles db User {userId} GroupInfo {groupId} members = do
 deleteGroupItemsAndMembers :: DB.Connection -> User -> GroupInfo -> [GroupMember] -> IO ()
 deleteGroupItemsAndMembers db user@User {userId} GroupInfo {groupId} members = do
   DB.execute db "DELETE FROM chat_items WHERE user_id = ? AND group_id = ?" (userId, groupId)
+  void $ runExceptT cleanupHostGroupLinkConn_ -- to allow repeat connection via the same group link if one was used
   DB.execute db "DELETE FROM group_members WHERE user_id = ? AND group_id = ?" (userId, groupId)
   forM_ members $ \m -> cleanupMemberContactAndProfile_ db user m
+  where
+    cleanupHostGroupLinkConn_ = do
+      hostId <- getHostMemberId_ db user groupId
+      liftIO $
+        DB.execute
+          db
+          [sql|
+            UPDATE connections SET via_contact_uri_hash = NULL, xcontact_id = NULL
+            WHERE user_id = ? AND via_group_link = 1 AND contact_id IN (
+              SELECT contact_id
+              FROM group_members
+              WHERE user_id = ? AND group_member_id = ?
+            )
+          |]
+          (userId, userId, hostId)
 
 deleteGroup :: DB.Connection -> User -> GroupInfo -> IO ()
 deleteGroup db User {userId} GroupInfo {groupId, localDisplayName} = do

tests/ChatTests.hs

@@ -144,6 +144,7 @@ chatTests = do
     it "set chat item TTL" testSetChatItemTTL
   describe "group links" $ do
     it "create group link, join via group link" testGroupLink
+    it "delete group, re-join via same link" testGroupLinkDeleteGroupRejoin
     it "sending message to contact created via group link marks it used" testGroupLinkContactUsed
     it "create group link, join via group link - incognito membership" testGroupLinkIncognitoMembership
   describe "queue rotation" $ do
@@ -3558,6 +3559,60 @@ testGroupLink =
       alice ##> "/show link #team"
       alice <## "no group link, to create: /create link #team"
 
+testGroupLinkDeleteGroupRejoin :: IO ()
+testGroupLinkDeleteGroupRejoin =
+  testChat2 aliceProfile bobProfile $
+    \alice bob -> do
+      alice ##> "/g team"
+      alice <## "group #team is created"
+      alice <## "use /a team <name> to add members"
+      alice ##> "/create link #team"
+      gLink <- getGroupLink alice "team" True
+      bob ##> ("/c " <> gLink)
+      bob <## "connection request sent!"
+      alice <## "bob (Bob): accepting request to join group #team..."
+      concurrentlyN_
+        [ do
+            alice <## "bob (Bob): contact is connected"
+            alice <## "bob invited to group #team via your group link"
+            alice <## "#team: bob joined the group",
+          do
+            bob <## "alice (Alice): contact is connected"
+            bob <## "#team: you joined the group"
+        ]
+      -- use contact so it's not deleted when deleting group
+      bob <##> alice
+      bob ##> "/l team"
+      concurrentlyN_
+        [ do
+            bob <## "#team: you left the group"
+            bob <## "use /d #team to delete the group",
+          alice <## "#team: bob left the group"
+        ]
+      bob ##> "/d #team"
+      bob <## "#team: you deleted the group"
+      -- re-join via same link
+      bob ##> ("/c " <> gLink)
+      bob <## "connection request sent!"
+      alice <## "bob_1 (Bob): accepting request to join group #team..."
+      concurrentlyN_
+        [ do
+            alice <## "bob_1 (Bob): contact is connected"
+            alice <## "bob_1 invited to group #team via your group link"
+            alice <## "contact bob_1 is merged into bob"
+            alice <## "use @bob <message> to send messages"
+            alice <## "#team: bob joined the group",
+          do
+            bob <## "alice_1 (Alice): contact is connected"
+            bob <## "contact alice_1 is merged into alice"
+            bob <## "use @alice <message> to send messages"
+            bob <## "#team: you joined the group"
+        ]
+      alice #> "#team hello"
+      bob <# "#team alice> hello"
+      bob #> "#team hi there"
+      alice <# "#team bob> hi there"
+
 testGroupLinkContactUsed :: IO ()
 testGroupLinkContactUsed =
   testChat2 aliceProfile bobProfile $
@@ -3565,14 +3620,8 @@ testGroupLinkContactUsed =
       alice ##> "/g team"
       alice <## "group #team is created"
       alice <## "use /a team <name> to add members"
-      alice ##> "/show link #team"
-      alice <## "no group link, to create: /create link #team"
       alice ##> "/create link #team"
       gLink <- getGroupLink alice "team" True
-      alice ##> "/show link #team"
-      _ <- getGroupLink alice "team" False
-      alice ##> "/create link #team"
-      alice <## "you already have link for this group, to show: /show link #team"
       bob ##> ("/c " <> gLink)
       bob <## "connection request sent!"
       alice <## "bob (Bob): accepting request to join group #team..."