Make revCacheLoaderForDocument work for winning revision channels not in history

Author: bbrks

db/crud.go

@@ -552,12 +552,7 @@ func (col *DatabaseCollectionWithUser) authorizeDoc(doc *Document, revid string)
 	}
 
 	if revid == doc.CurrentRev {
-		ch := base.SetOf()
-		for channelName, channelRemoval := range doc.Channels {
-			if channelRemoval == nil || channelRemoval.Seq == 0 {
-				ch.Add(channelName)
-			}
-		}
+		ch := doc.currentChannels()
 		return col.user.AuthorizeAnyCollectionChannel(col.ScopeName, col.Name, ch)
 	} else if rev := doc.History[revid]; rev != nil {
 		// Authenticate against specific revision:

db/document.go

@@ -1226,3 +1226,14 @@ func (doc *Document) MarshalWithXattr() (data []byte, xdata []byte, err error) {
 
 	return data, xdata, nil
 }
+
+// Returns a set of the current (winning revision's) channels for the document.
+func (doc *Document) currentChannels() base.Set {
+	ch := base.SetOf()
+	for channelName, channelRemoval := range doc.Channels {
+		if channelRemoval == nil || channelRemoval.Seq == 0 {
+			ch.Add(channelName)
+		}
+	}
+	return ch
+}

db/revision_cache_interface.go

@@ -283,7 +283,11 @@ func revCacheLoaderForDocument(ctx context.Context, backingStore RevisionCacheBa
 		return bodyBytes, body, history, channels, removed, nil, deleted, nil, getHistoryErr
 	}
 	history = encodeRevisions(doc.ID, validatedHistory)
-	channels = doc.History[revid].Channels
+	if doc.CurrentRev == revid {
+		channels = doc.currentChannels()
+	} else {
+		channels = doc.History[revid].Channels
+	}
 
 	return bodyBytes, body, history, channels, removed, attachments, deleted, doc.Expiry, err
 }