fixup! rework argument handling

This commit tweaks the argument handling based on the suggestion
by @achilleas-k (thanks!). Now it takes
```console
$ image-builder manifest centos-9 qcow2 ./path/to/blueprint
...
$ image-builder manifest --arch s390x centos-9 qcow2
...
```

This means it is no longer copy/paste friendly from `--list-images`
but we can tweak the output of that so that by default we only
how `distro:foo type:bar` instead of the full arch string and
hint via something like `isatty(0)` for interactive users that
there are more arches available.

cmd/image-builder/main.go

@@ -42,18 +42,19 @@ func cmdManifest(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
-	blueprintPath, err := cmd.Flags().GetString("blueprint")
+	archStr, err := cmd.Flags().GetString("arch")
 	if err != nil {
 		return err
 	}
+	if archStr == "" {
+		archStr = arch.Current().String()
+	}
 
+	var blueprintPath string
 	distroStr := args[0]
 	imgTypeStr := args[1]
-	var archStr string
 	if len(args) > 2 {
-		archStr = args[2]
-	} else {
-		archStr = arch.Current().String()
+		blueprintPath = args[2]
 	}
 	res, err := getOneImage(dataDir, distroStr, imgTypeStr, archStr)
 	if err != nil {
@@ -109,15 +110,14 @@ operating sytsems like centos and RHEL with easy customizations support.`,
 	rootCmd.AddCommand(listImagesCmd)
 
 	manifestCmd := &cobra.Command{
-		Use:          "manifest <distro> <image-type> [<arch>]",
+		Use:          "manifest <distro> <image-type> [blueprint]",
 		Short:        "Build manifest for the given distro/image-type, e.g. centos-9 qcow2",
 		RunE:         cmdManifest,
 		SilenceUsage: true,
 		Args:         cobra.MinimumNArgs(2),
 		Hidden:       true,
 	}
-	// XXX: share with build
-	manifestCmd.Flags().String("blueprint", "", `pass a blueprint file`)
+	manifestCmd.Flags().String("arch", "", `build manifest for a different architecture`)
 	rootCmd.AddCommand(manifestCmd)
 
 	return rootCmd.Execute()

cmd/image-builder/main_test.go

@@ -170,9 +170,9 @@ func TestManifestIntegrationSmoke(t *testing.T) {
 
 	restore = main.MockOsArgs([]string{
 		"manifest",
-		"--blueprint", makeTestBlueprint(t, testBlueprint),
-		"centos-9", "qcow2"},
-	)
+		"centos-9", "qcow2",
+		makeTestBlueprint(t, testBlueprint),
+	})
 	defer restore()
 
 	var fakeStdout bytes.Buffer
@@ -190,3 +190,36 @@ func TestManifestIntegrationSmoke(t *testing.T) {
 	assert.Contains(t, fakeStdout.String(), `{"type":"org.osbuild.users","options":{"users":{"alice":{}}}}`)
 	assert.Contains(t, fakeStdout.String(), `"image":{"name":"registry.gitlab.com/redhat/services/products/image-builder/ci/osbuild-composer/fedora-minimal"`)
 }
+
+func TestManifestIntegrationCrossArch(t *testing.T) {
+	if testing.Short() {
+		t.Skip("manifest generation takes a while")
+	}
+	if !hasDepsolveDnf() {
+		t.Skip("no osbuild-depsolve-dnf binary found")
+	}
+
+	restore := main.MockNewRepoRegistry(testrepos.New)
+	defer restore()
+
+	restore = main.MockOsArgs([]string{
+		"manifest",
+		"centos-9", "tar",
+		"--arch", "s390x",
+	})
+	defer restore()
+
+	var fakeStdout bytes.Buffer
+	restore = main.MockOsStdout(&fakeStdout)
+	defer restore()
+
+	err := main.Run()
+	assert.NoError(t, err)
+
+	pipelineNames, err := manifesttest.PipelineNamesFrom(fakeStdout.Bytes())
+	assert.NoError(t, err)
+	assert.Contains(t, pipelineNames, "archive")
+
+	// XXX: provide helpers in manifesttest to extract this in a nicer way
+	assert.Contains(t, fakeStdout.String(), `.el9.s390x.rpm`)
+}