skip/fail upgrade if no longer matches a platform

cmd/krew/cmd/upgrade.go

@@ -41,9 +41,11 @@ To only upgrade single plugins provide them as arguments:
 kubectl krew upgrade foo bar"`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			var ignoreUpgraded bool
+			var skipErrors bool
+
 			var pluginNames []string
-			// Upgrade all plugins.
 			if len(args) == 0 {
+				// Upgrade all plugins.
 				installed, err := installation.ListInstalledPlugins(paths.InstallReceiptsPath())
 				if err != nil {
 					return errors.Wrap(err, "failed to find all installed versions")
@@ -52,10 +54,13 @@ kubectl krew upgrade foo bar"`,
 					pluginNames = append(pluginNames, name)
 				}
 				ignoreUpgraded = true
+				skipErrors = true
 			} else {
+				// Upgrade certain plugins
 				pluginNames = args
 			}
 
+			var nErrors int
 			for _, name := range pluginNames {
 				plugin, err := indexscanner.LoadPluginFileFromFS(paths.IndexPluginsPath(), name)
 				if err != nil {
@@ -69,11 +74,19 @@ kubectl krew upgrade foo bar"`,
 					continue
 				}
 				if err != nil {
+					nErrors++
+					if skipErrors {
+						fmt.Fprintf(os.Stderr, "WARNING: failed to upgrade plugin %q, skipping (error: %v)\n", plugin.Name, err)
+						continue
+					}
 					return errors.Wrapf(err, "failed to upgrade plugin %q", plugin.Name)
 				}
 				fmt.Fprintf(os.Stderr, "Upgraded plugin: %s\n", plugin.Name)
 				internal.PrintSecurityNotice()
 			}
+			if nErrors > 0 {
+				fmt.Fprintf(os.Stderr, "WARNING: Some plugins failed to upgrade, check logs above.\n")
+			}
 			return nil
 		},
 		PreRunE: func(cmd *cobra.Command, args []string) error {

integration_test/upgrade_test.go

@@ -17,6 +17,7 @@ package integrationtest
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"sigs.k8s.io/krew/pkg/constants"
@@ -49,6 +50,31 @@ func TestKrewUpgrade(t *testing.T) {
 	}
 }
 
+func TestKrewUpgradeWhenPlatformNoLongerMatches(t *testing.T) {
+	skipShort(t)
+
+	test, cleanup := NewTest(t)
+	defer cleanup()
+
+	test.WithIndex().
+		Krew("install", validPlugin).
+		RunOrFail()
+
+	test.WithEnv("KREW_OS", "somethingelse")
+
+	// if upgrading 'all' plugins, must succeed
+	out := string(test.Krew("upgrade", "--no-update-index").RunOrFailOutput())
+	if !strings.Contains(out, "WARNING: Some plugins failed to upgrade") {
+		t.Fatalf("upgrade all plugins output doesn't contain warnings about failed plugins:\n%s", out)
+	}
+
+	// if upgrading a specific plugin, it must fail, because no longer matching to a platform
+	err := test.Krew("upgrade", validPlugin, "--no-update-index").Run()
+	if err == nil {
+		t.Fatal("expected failure when upgraded a specific plugin that no longer has a matching platform")
+	}
+}
+
 func resolvePluginSymlink(test *ITest, plugin string) string {
 	test.t.Helper()
 	linkToPlugin, err := test.LookupExecutable("kubectl-" + plugin)

internal/installation/upgrade.go

@@ -48,7 +48,8 @@ func Upgrade(p environment.Paths, plugin index.Plugin) error {
 		return errors.Wrap(err, "failed trying to find a matching platform in plugin spec")
 	}
 	if !ok {
-		return errors.Wrapf(err, "plugin %q does not offer installation for this platform", plugin.Name)
+		os, arch := osArch()
+		return errors.Errorf("plugin %q does not offer installation for this platform (%s/%s)", plugin.Name, os, arch)
 	}
 
 	newVersion := plugin.Spec.Version