Tweak LoadMembershipAtEvent behaviour when state not known (#2716)

Previously `LoadMembershipAtEvent` would fail if the state before one of
the events was not known, i.e. because it was an outlier. This modifies
it so that it gracefully handles not knowing the state and returns no
memberships instead, so that history visibility doesn't freak out and
kill `/sync` requests dead.
This commit is contained in:
Neil Alexander 2022-09-13 12:52:09 +01:00 committed by GitHub
parent 3e55856254
commit b05e028f7d
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
4 changed files with 18 additions and 7 deletions

View file

@ -18,6 +18,7 @@ package state
import (
"context"
"database/sql"
"fmt"
"sort"
"sync"
@ -134,11 +135,14 @@ func (v *StateResolution) LoadMembershipAtEvent(
for i := range eventIDs {
eventID := eventIDs[i]
snapshotNID, err := v.db.SnapshotNIDFromEventID(ctx, eventID)
if err != nil {
if err != nil && err != sql.ErrNoRows {
return nil, fmt.Errorf("LoadStateAtEvent.SnapshotNIDFromEventID failed for event %s : %w", eventID, err)
}
if snapshotNID == 0 {
return nil, fmt.Errorf("LoadStateAtEvent.SnapshotNIDFromEventID(%s) returned 0 NID, was this event stored?", eventID)
// If we don't know a state snapshot for this event then we can't calculate
// memberships at the time of the event, so skip over it. This means that
// it isn't guaranteed that the response map will contain every single event.
continue
}
snapshotNIDMap[snapshotNID] = append(snapshotNIDMap[snapshotNID], eventID)
}