Ensure plugins default search path obeys --config

A static global initialiser happens before the arguments are parsed, so we need
to calculate the path later.

Signed-off-by: Ian Campbell <ijc@docker.com>

cli-plugins/manager/manager.go

@@ -29,15 +29,13 @@ func IsNotFound(err error) bool {
 	return ok
 }
 
-var defaultUserPluginDir = config.Path("cli-plugins")
-
 func getPluginDirs(dockerCli command.Cli) []string {
 	var pluginDirs []string
 
 	if cfg := dockerCli.ConfigFile(); cfg != nil {
 		pluginDirs = append(pluginDirs, cfg.CLIPluginsExtraDirs...)
 	}
-	pluginDirs = append(pluginDirs, defaultUserPluginDir)
+	pluginDirs = append(pluginDirs, config.Path("cli-plugins"))
 	pluginDirs = append(pluginDirs, defaultSystemPluginDirs...)
 	return pluginDirs
 }

cli-plugins/manager/manager_test.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/docker/cli/cli/config"
 	"github.com/docker/cli/cli/config/configfile"
 	"github.com/docker/cli/internal/test"
 	"gotest.tools/assert"
@@ -91,7 +92,7 @@ func TestErrPluginNotFound(t *testing.T) {
 func TestGetPluginDirs(t *testing.T) {
 	cli := test.NewFakeCli(nil)
 
-	expected := []string{defaultUserPluginDir}
+	expected := []string{config.Path("cli-plugins")}
 	expected = append(expected, defaultSystemPluginDirs...)
 
 	assert.Equal(t, strings.Join(expected, ":"), strings.Join(getPluginDirs(cli), ":"))