osbuild: rework XZ stage inputs

The `FilesInputs` was since the beginning an XZ-specific implementation
of the input, but it was implemented in the `files_input.go` in a false
hope that it could be used as a generic stage inputs by any stages. It
turned out that various stages require different implementation of
its input. Specifically there is usually a stage-specific key, which has
assigned a common input type. For XZ stage, the key is `file`.

Remove `FilesInputs` and instead implement `XzStageInputs` which is now
accepted by the XZ stage.

Fix all affected pipeline implementations that use XZ stage.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

internal/manifest/coi_iso_tree.go

@@ -64,7 +64,7 @@ func (p *CoreOSISOTree) serialize() osbuild.Pipeline {
 				},
 			},
 		},
-		osbuild.NewFilesInputs(osbuild.NewFilesInputPipelineObjectRef(p.payloadPipeline.Name(), p.payloadPipeline.Filename, nil)),
+		osbuild.NewXzStageInputs(osbuild.NewFilesInputPipelineObjectRef(p.payloadPipeline.Name(), p.payloadPipeline.Filename, nil)),
 	))
 
 	if p.coiPipeline.Ignition != nil {

internal/manifest/xz.go

@@ -33,7 +33,7 @@ func (p *XZ) serialize() osbuild.Pipeline {
 
 	pipeline.AddStage(osbuild.NewXzStage(
 		osbuild.NewXzStageOptions(p.Filename),
-		osbuild.NewFilesInputs(osbuild.NewFilesInputPipelineObjectRef(p.imgPipeline.Name(), p.imgPipeline.Export().Filename(), nil)),
+		osbuild.NewXzStageInputs(osbuild.NewFilesInputPipelineObjectRef(p.imgPipeline.Name(), p.imgPipeline.Export().Filename(), nil)),
 	))
 
 	return pipeline

internal/osbuild/files_input.go

@@ -5,25 +5,6 @@ import (
 	"fmt"
 )
 
-// Inputs for individual files
-
-type FilesInputs struct {
-	File *FilesInput `json:"file"`
-}
-
-func (FilesInputs) isStageInputs() {}
-
-func NewFilesInputs(references FilesInputRef) *FilesInputs {
-	return &FilesInputs{
-		File: NewFilesInput(references),
-	}
-}
-
-// IMPLEMENTED INTERFACES OF STAGES ACCEPTING THIS INPUTS TYPE
-
-// inputs accepted by the XZ stage
-func (FilesInputs) isXzStageInputs() {}
-
 // SPECIFIC INPUT STRUCTURE
 
 type FilesInput struct {

internal/osbuild/files_input_test.go

@@ -2,40 +2,11 @@ package osbuild
 
 import (
 	"encoding/json"
-	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-type fakeFilesInputRef struct{}
-
-func (f *fakeFilesInputRef) isFilesInputRef() {}
-
-func TestNewFilesInputs(t *testing.T) {
-	inputFilename := "image.raw"
-	pipeline := "os"
-
-	expectedInput := &FilesInputs{
-		File: &FilesInput{
-			inputCommon: inputCommon{
-				Type:   InputTypeFiles,
-				Origin: InputOriginPipeline,
-			},
-			References: &FilesInputPipelineObjectRef{
-				fmt.Sprintf("name:%s", pipeline): FilesInputPipelineOptions{File: inputFilename},
-			},
-		},
-	}
-
-	actualInput := NewFilesInputs(NewFilesInputPipelineObjectRef(pipeline, inputFilename, nil))
-	assert.Equal(t, expectedInput, actualInput)
-
-	assert.Panics(t, func() {
-		NewFilesInputs(&fakeFilesInputRef{})
-	})
-}
-
 func TestFilesInput_UnmarshalJSON(t *testing.T) {
 	testCases := []struct {
 		name    string

internal/osbuild/xz_stage.go

@@ -13,15 +13,23 @@ func NewXzStageOptions(filename string) *XzStageOptions {
 	}
 }
 
-type XzStageInputs interface {
-	isXzStageInputs()
+type XzStageInputs struct {
+	File *FilesInput `json:"file"`
+}
+
+func (*XzStageInputs) isStageInputs() {}
+
+func NewXzStageInputs(references FilesInputRef) *XzStageInputs {
+	return &XzStageInputs{
+		File: NewFilesInput(references),
+	}
 }
 
 // Compresses a file into a xz archive.
-func NewXzStage(options *XzStageOptions, inputs XzStageInputs) *Stage {
+func NewXzStage(options *XzStageOptions, inputs *XzStageInputs) *Stage {
 	var stageInputs Inputs
 	if inputs != nil {
-		stageInputs = inputs.(Inputs)
+		stageInputs = inputs
 	}
 
 	return &Stage{

internal/osbuild/xz_stage_test.go

@@ -25,11 +25,11 @@ func TestNewXzStage(t *testing.T) {
 	expectedStage := &Stage{
 		Type:    "org.osbuild.xz",
 		Options: NewXzStageOptions(filename),
-		Inputs:  NewFilesInputs(NewFilesInputPipelineObjectRef(pipeline, inputFilename, nil)),
+		Inputs:  NewXzStageInputs(NewFilesInputPipelineObjectRef(pipeline, inputFilename, nil)),
 	}
 
 	actualStage := NewXzStage(NewXzStageOptions(filename),
-		NewFilesInputs(NewFilesInputPipelineObjectRef(pipeline, inputFilename, nil)))
+		NewXzStageInputs(NewFilesInputPipelineObjectRef(pipeline, inputFilename, nil)))
 	assert.Equal(t, expectedStage, actualStage)
 }