Fix crash in membership updater (#1753)

* Fix nil pointer exception in membership updater

* goimports
This commit is contained in:
Neil Alexander 2021-02-06 11:49:18 +00:00 committed by GitHub
parent 397b158c05
commit 02e6d89cc2
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@ -107,6 +107,23 @@ func (r *Inputer) updateMembership(
return updates, nil return updates, nil
} }
// In an ideal world, we shouldn't ever have "add" be nil and "remove" be
// set, as this implies that we're deleting a state event without replacing
// it (a thing that ordinarily shouldn't happen in Matrix). However, state
// resets are sadly a thing occasionally and we have to account for that.
// Beforehand there used to be a check here which stopped dead if we hit
// this scenario, but that meant that the membership table got out of sync
// after a state reset, often thinking that the user was still joined to
// the room even though the room state said otherwise, and this would prevent
// the user from being able to attempt to rejoin the room without modifying
// the database. So instead what we'll do is we'll just update the membership
// table to say that the user is "leave" and we'll use the old event to
// avoid nil pointer exceptions on the code path that follows.
if add == nil {
add = remove
newMembership = gomatrixserverlib.Leave
}
mu, err := updater.MembershipUpdater(targetUserNID, r.isLocalTarget(add)) mu, err := updater.MembershipUpdater(targetUserNID, r.isLocalTarget(add))
if err != nil { if err != nil {
return nil, err return nil, err