updates

Signed-off-by: Patrick Zheng <[email protected]>

cmd/notation/plugin/install.go

@@ -96,8 +96,8 @@ Example - Install plugin from URL, SHA256 checksum is required:
 		},
 	}
 	opts.LoggingFlagOpts.ApplyFlags(command.Flags())
-	command.Flags().BoolVar(&opts.isFile, "file", false, "if set, install plugin from a file in file system")
-	command.Flags().BoolVar(&opts.isUrl, "url", false, " if set, install plugin from a HTTPS URL")
+	command.Flags().BoolVar(&opts.isFile, "file", false, "install plugin from a file in file system")
+	command.Flags().BoolVar(&opts.isUrl, "url", false, " install plugin from a HTTPS URL")
 	command.Flags().StringVar(&opts.inputCheckSum, "sha256sum", "", "must match SHA256 of the plugin source")
 	command.Flags().BoolVar(&opts.force, "force", false, "force the installation of a plugin")
 	command.MarkFlagsMutuallyExclusive("file", "url")
@@ -284,23 +284,25 @@ func installPluginExecutable(ctx context.Context, fileName string, pluginName st
 	}
 	pluginVersion := pluginMetadata.Version
 	// check plugin existence and version
+	var currentPluginVersion string
 	if !force {
 		currentPluginMetadata, err := notationplugin.GetPluginMetadataIfExist(ctx, pluginName)
 		if err != nil && !errors.Is(err, os.ErrNotExist) {
 			return err
 		}
+		currentPluginVersion = currentPluginMetadata.Version
 		if err == nil { // plugin already installed
-			comp, err := notationplugin.ComparePluginVersion(pluginVersion, currentPluginMetadata.Version)
+			comp, err := notationplugin.ComparePluginVersion(pluginVersion, currentPluginVersion)
 			if err != nil {
 				return err
 			}
 			if comp < 0 {
-				return fmt.Errorf("%s current version %s is larger than the installing version %s. To view a list of installed plugins, use `notation plugin list`", pluginName, currentPluginMetadata.Version, pluginVersion)
+				return fmt.Errorf("%s current version %s is higher than the installing version %s.\n To view a list of installed plugins, use `notation plugin list`. If you want to install an old version, use \"--force\" to force the installation", pluginName, currentPluginVersion, pluginVersion)
 			}
 			if comp == 0 {
 				// if version is the same, no action is needed and no error is
 				// returned
-				fmt.Printf("Plugin %s with version %s is already installed. To view a list of installed plugins, use `notation plugin list`.\n", pluginName, currentPluginMetadata.Version)
+				fmt.Printf("Plugin %s with version %s already exists.\n To view a list of installed plugins, use `notation plugin list`.\n", pluginName, currentPluginVersion)
 				return nil
 			}
 		}
@@ -320,6 +322,10 @@ func installPluginExecutable(ctx context.Context, fileName string, pluginName st
 	if err != nil {
 		return err
 	}
-	fmt.Printf("Succussefully installed plugin %s, version %s\n", pluginName, pluginVersion)
+	if currentPluginVersion != "" {
+		fmt.Printf("Succussefully installed plugin %s, updated the version from %s to %s\n", pluginName, currentPluginVersion, pluginVersion)
+	} else {
+		fmt.Printf("Succussefully installed plugin %s, version %s\n", pluginName, pluginVersion)
+	}
 	return nil
 }

test/e2e/suite/plugin/install.go

@@ -45,7 +45,7 @@ var _ = Describe("notation plugin install", func() {
 				MatchContent("Succussefully installed plugin e2e-plugin, version 1.0.0\n")
 
 			notation.Exec("plugin", "install", "--file", NotationE2EPluginTarGzPath).
-				MatchContent("Plugin e2e-plugin with version 1.0.0 is already installed. To view a list of installed plugins, use `notation plugin list`.\n")
+				MatchContent("Plugin e2e-plugin with version 1.0.0 already exists.\n To view a list of installed plugins, use `notation plugin list`.\n")
 		})
 	})