Fixes ImageList to be retro-compatible with older API

Make sure current client code can talk for ImageList can still talk to
older daemon.

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

api/types/filters/parse.go

@@ -144,6 +144,9 @@ func (filters Args) Add(name, value string) {
 func (filters Args) Del(name, value string) {
 	if _, ok := filters.fields[name]; ok {
 		delete(filters.fields[name], value)
+		if len(filters.fields[name]) == 0 {
+			delete(filters.fields, name)
+		}
 	}
 }
 

client/image_list.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/api/types/versions"
 	"golang.org/x/net/context"
 )
 
@@ -14,8 +15,16 @@ func (cli *Client) ImageList(ctx context.Context, options types.ImageListOptions
 	var images []types.ImageSummary
 	query := url.Values{}
 
-	if options.Filters.Len() > 0 {
-		filterJSON, err := filters.ToParamWithVersion(cli.version, options.Filters)
+	optionFilters := options.Filters
+	referenceFilters := optionFilters.Get("reference")
+	if versions.LessThan(cli.version, "1.25") && len(referenceFilters) > 0 {
+		query.Set("filter", referenceFilters[0])
+		for _, filterValue := range referenceFilters {
+			optionFilters.Del("reference", filterValue)
+		}
+	}
+	if optionFilters.Len() > 0 {
+		filterJSON, err := filters.ToParamWithVersion(cli.version, optionFilters)
 		if err != nil {
 			return images, err
 		}

client/image_list_test.go

@@ -109,3 +109,51 @@ func TestImageList(t *testing.T) {
 		}
 	}
 }
+
+func TestImageListApiBefore125(t *testing.T) {
+	expectedFilter := "image:tag"
+	client := &Client{
+		client: newMockClient(func(req *http.Request) (*http.Response, error) {
+			query := req.URL.Query()
+			actualFilter := query.Get("filter")
+			if actualFilter != expectedFilter {
+				return nil, fmt.Errorf("filter not set in URL query properly. Expected '%s', got %s", expectedFilter, actualFilter)
+			}
+			actualFilters := query.Get("filters")
+			if actualFilters != "" {
+				return nil, fmt.Errorf("filters should have not been present, were with value: %s", actualFilters)
+			}
+			content, err := json.Marshal([]types.ImageSummary{
+				{
+					ID: "image_id2",
+				},
+				{
+					ID: "image_id2",
+				},
+			})
+			if err != nil {
+				return nil, err
+			}
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Body:       ioutil.NopCloser(bytes.NewReader(content)),
+			}, nil
+		}),
+		version: "1.24",
+	}
+
+	filters := filters.NewArgs()
+	filters.Add("reference", "image:tag")
+
+	options := types.ImageListOptions{
+		Filters: filters,
+	}
+
+	images, err := client.ImageList(context.Background(), options)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(images) != 2 {
+		t.Fatalf("expected 2 images, got %v", images)
+	}
+}