Return exit code 0 when a core is already up to date (#2207)

* fix wrong type assertion

* use feedback.Fatal otherwise it won't flush the stdout as json format

* use feedback.PrintResult instead of using fatal

* use errors.As in case in the future the err coming from PlatformUpgrade might be wrapped

errors.As search through all the wrapped error for our target type, in case it finds it then it popolate that struct but more important we can use it as a type assertion even if is nested through many errors

Author: alessio-perugini

Diff for: internal/cli/core/upgrade.go

@@ -110,8 +110,9 @@ func Upgrade(inst *rpc.Instance, args []string, skipPostInstall bool) {
 		response, err := core.PlatformUpgrade(context.Background(), r, feedback.ProgressBar(), feedback.TaskProgress())
 		warningMissingIndex(response)
 		if err != nil {
-			if errors.Is(err, &arduino.PlatformAlreadyAtTheLatestVersionError{}) {
-				feedback.Print(err.Error())
+			var alreadyAtLatestVersionErr *arduino.PlatformAlreadyAtTheLatestVersionError
+			if errors.As(err, &alreadyAtLatestVersionErr) {
+				feedback.Warning(err.Error())
 				continue
 			}
 
@@ -122,4 +123,19 @@ func Upgrade(inst *rpc.Instance, args []string, skipPostInstall bool) {
 	if hasBadArguments {
 		feedback.Fatal(tr("Some upgrades failed, please check the output for details."), feedback.ErrBadArgument)
 	}
+
+	feedback.PrintResult(&platformUpgradeResult{})
+}
+
+// This is needed so we can print warning messages in case users use --format json
+type platformUpgradeResult struct{}
+
+// Data implements feedback.Result.
+func (r *platformUpgradeResult) Data() interface{} {
+	return r
+}
+
+// String implements feedback.Result.
+func (r *platformUpgradeResult) String() string {
+	return ""
 }

Diff for: internal/integrationtest/core/core_test.go

@@ -1041,16 +1041,16 @@ func TestCoreUpgradeWarningWithPackageInstalledButNotIndexed(t *testing.T) {
 		_, _, err = cli.Run("core", "install", "test:[email protected]", "--additional-urls="+url)
 		require.NoError(t, err)
 		//upgrade without index fires a warning
-		_, jsonStderr, _ := cli.Run("core", "upgrade", "test:x86", "--format", "json")
-		requirejson.Query(t, jsonStderr, ".warnings[]", `"missing package index for test:x86, future updates cannot be guaranteed"`)
+		jsonStdout, _, _ := cli.Run("core", "upgrade", "test:x86", "--format", "json")
+		requirejson.Query(t, jsonStdout, ".warnings[]", `"missing package index for test:x86, future updates cannot be guaranteed"`)
 	})
 
 	// removing installed.json
 	installedJson := cli.DataDir().Join("packages", "test", "hardware", "x86", "1.0.0", "installed.json")
 	require.NoError(t, os.Remove(installedJson.String()))
 
 	t.Run("missing both installed.json and additional-urls", func(t *testing.T) {
-		_, jsonStderr, _ := cli.Run("core", "upgrade", "test:x86", "--format", "json")
-		requirejson.Query(t, jsonStderr, ".warnings[]", `"missing package index for test:x86, future updates cannot be guaranteed"`)
+		jsonStdout, _, _ := cli.Run("core", "upgrade", "test:x86", "--format", "json")
+		requirejson.Query(t, jsonStdout, ".warnings[]", `"missing package index for test:x86, future updates cannot be guaranteed"`)
 	})
 }