cache_to and cache_from are now string instead of cli.StringSlice

cmd/docker-buildx/config.go

@@ -195,13 +195,13 @@ func settingsFlags(settings *plugin.Settings) []cli.Flag {
 			Usage:       "sets the build target to use",
 			Destination: &settings.Build.Target,
 		},
-		&cli.StringSliceFlag{
+		&cli.StringFlag{
 			Name:        "cache-from",
 			EnvVars:     []string{"PLUGIN_CACHE_FROM"},
 			Usage:       "sets images to consider as cache sources",
 			Destination: &settings.Build.CacheFrom,
 		},
-		&cli.StringSliceFlag{
+		&cli.StringFlag{
 			Name:        "cache-to",
 			EnvVars:     []string{"PLUGIN_CACHE_TO"},
 			Usage:       "cache destination for the build cache",

plugin/docker.go

@@ -78,11 +78,11 @@ func commandBuild(build Build, dryrun bool) *exec.Cmd {
 	if build.NoCache {
 		args = append(args, "--no-cache")
 	}
-	for _, arg := range build.CacheFrom.Value() {
-		args = append(args, "--cache-from", arg)
+	if build.CacheFrom != "" {
+		args = append(args, "--cache-from", build.CacheFrom)
 	}
-	for _, arg := range build.CacheTo.Value() {
-		args = append(args, "--cache-to", arg)
+	if build.CacheTo != "" {
+		args = append(args, "--cache-to", build.CacheTo)
 	}
 	for _, arg := range build.ArgsEnv.Value() {
 		addProxyValue(&build, arg)

plugin/impl.go

@@ -72,8 +72,8 @@ type Build struct {
 	Target          string          // Docker build target
 	Output          string          // Docker build output
 	Pull            bool            // Docker build pull
-	CacheFrom       cli.StringSlice // Docker build cache-from
-	CacheTo         cli.StringSlice // Docker build cache-to
+	CacheFrom       string          // Docker build cache-from
+	CacheTo         string          // Docker build cache-to
 	Compress        bool            // Docker build compress
 	Repo            cli.StringSlice // Docker build repository
 	NoCache         bool            // Docker build no-cache