X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/bd857c2152f66bc17745edcc5a7a88377024ff43..d4ed3e6460469f2766e1f1676c538d6c86e000b6:/lib/controller/federation/list.go

diff --git a/lib/controller/federation/list.go b/lib/controller/federation/list.go
index 43ed2cdbaa..414870d24f 100644
--- a/lib/controller/federation/list.go
+++ b/lib/controller/federation/list.go
@@ -68,8 +68,7 @@ func (conn *Conn) CollectionList(ctx context.Context, options arvados.ListOption
 //
 // * len(Order)==0
 //
-// * there are no filters other than the "uuid = ..." and "uuid in
-//   ..." filters mentioned above.
+// * Each filter must be either "uuid = ..." or "uuid in [...]".
 //
 // * The maximum possible response size (total number of objects that
 //   could potentially be matched by all of the specified filters)
@@ -140,6 +139,11 @@ func (conn *Conn) splitListRequest(ctx context.Context, opts arvados.ListOptions
 		}
 	}
 
+	// Collate UUIDs in matchAllFilters by remote cluster ID --
+	// e.g., todoByRemote["aaaaa"]["aaaaa-4zz18-000000000000000"]
+	// will be true -- and count the total number of UUIDs we're
+	// filtering on, so we can compare it to our max page size
+	// limit.
 	nUUIDs := 0
 	todoByRemote := map[string]map[string]bool{}
 	for uuid := range matchAllFilters {
@@ -156,7 +160,7 @@ func (conn *Conn) splitListRequest(ctx context.Context, opts arvados.ListOptions
 
 	if len(todoByRemote) > 1 {
 		if cannotSplit {
-			return httpErrorf(http.StatusBadRequest, "cannot execute federated list query with filters other than 'uuid = ...' and 'uuid in [...]'")
+			return httpErrorf(http.StatusBadRequest, "cannot execute federated list query: each filter must be either 'uuid = ...' or 'uuid in [...]'")
 		}
 		if opts.Count != "none" {
 			return httpErrorf(http.StatusBadRequest, "cannot execute federated list query unless count==\"none\"")