`ec.encode`: Fix resolution of target collections. (#6585)

* Don't ignore empty (`""`) collection names when computing collections for a given volume ID.

* `ec.encode`: Fix resolution of target collections.

When no `volumeId` parameter is provided, compute volumes
based on the provided collection name, even if it's empty (`""`).

This restores behavior to before recent EC rebalancing rework. See also
ec30a504ba/weed/shell/command_ec_encode.go (L99) .

weed/shell/command_ec_common.go

@@ -248,14 +248,14 @@ func collectCollectionsForVolumeIds(t *master_pb.TopologyInfo, vids []needle.Vol
 				for _, diskInfo := range dn.DiskInfos {
 					for _, vi := range diskInfo.VolumeInfos {
 						for _, vid := range vids {
-							if needle.VolumeId(vi.Id) == vid && vi.Collection != "" {
+							if needle.VolumeId(vi.Id) == vid {
 								found[vi.Collection] = true
 							}
 						}
 					}
 					for _, ecs := range diskInfo.EcShardInfos {
 						for _, vid := range vids {
-							if needle.VolumeId(ecs.Id) == vid && ecs.Collection != "" {
+							if needle.VolumeId(ecs.Id) == vid {
 								found[ecs.Collection] = true
 							}
 						}

weed/shell/command_ec_common_test.go

@@ -45,9 +45,9 @@ func TestCollectCollectionsForVolumeIds(t *testing.T) {
 		{topology1, nil, nil},
 		{topology1, []needle.VolumeId{}, nil},
 		{topology1, []needle.VolumeId{needle.VolumeId(9999)}, nil},
-		{topology1, []needle.VolumeId{needle.VolumeId(2)}, nil},
-		{topology1, []needle.VolumeId{needle.VolumeId(2), needle.VolumeId(272)}, []string{"collection2"}},
-		{topology1, []needle.VolumeId{needle.VolumeId(2), needle.VolumeId(272), needle.VolumeId(299)}, []string{"collection2"}},
+		{topology1, []needle.VolumeId{needle.VolumeId(2)}, []string{""}},
+		{topology1, []needle.VolumeId{needle.VolumeId(2), needle.VolumeId(272)}, []string{"", "collection2"}},
+		{topology1, []needle.VolumeId{needle.VolumeId(2), needle.VolumeId(272), needle.VolumeId(299)}, []string{"", "collection2"}},
 		{topology1, []needle.VolumeId{needle.VolumeId(272), needle.VolumeId(299), needle.VolumeId(95)}, []string{"collection1", "collection2"}},
 		{topology1, []needle.VolumeId{needle.VolumeId(272), needle.VolumeId(299), needle.VolumeId(95), needle.VolumeId(51)}, []string{"collection1", "collection2"}},
 		{topology1, []needle.VolumeId{needle.VolumeId(272), needle.VolumeId(299), needle.VolumeId(95), needle.VolumeId(51), needle.VolumeId(15)}, []string{"collection0", "collection1", "collection2"}},

weed/shell/command_ec_encode.go

@@ -98,23 +98,19 @@ func (c *commandEcEncode) Do(args []string, commandEnv *CommandEnv, writer io.Wr
 		}
 	}
 
+	var collections []string
 	var volumeIds []needle.VolumeId
 	if vid := needle.VolumeId(*volumeId); vid != 0 {
 		// volumeId is provided
 		volumeIds = append(volumeIds, vid)
+		collections = collectCollectionsForVolumeIds(topologyInfo, volumeIds)
 	} else {
-		// apply to all volumes in the collection
+		// apply to all volumes for the given collection
 		volumeIds, err = collectVolumeIdsForEcEncode(commandEnv, *collection, *fullPercentage, *quietPeriod)
 		if err != nil {
 			return err
 		}
-	}
-
-	var collections []string
-	if *collection != "" {
-		collections = []string{*collection}
-	} else {
-		collections = collectCollectionsForVolumeIds(topologyInfo, volumeIds)
+		collections = append(collections, *collection)
 	}
 
 	// encode all requested volumes...