parallels: error when no VM file found in source

The post-processor, when consuming a parallels artifact, checks for the
presence of a pvm or macvm file from the files of the artifact
received, and copies it in the output box for vagrant to use later.
However, if the artifact does not contain a compatible file, the
post-processor does not error, and instead returns a success, leading to
an unusable box being produced.

To avoid this, we count the files copied, and if none were, the box will
be unusable, so the post-processor errors now.

post-processor/vagrant/parallels.go

@@ -25,6 +25,8 @@ func (p *ParallelsProvider) Process(ui packersdk.Ui, artifact packersdk.Artifact
 	// Create the metadata
 	metadata = map[string]interface{}{"provider": "parallels"}
 
+	var copied int
+
 	// Copy all of the original contents into the temporary directory
 	for _, path := range artifact.Files() {
 		// If the file isn't critical to the function of the
@@ -55,6 +57,11 @@ func (p *ParallelsProvider) Process(ui packersdk.Ui, artifact packersdk.Artifact
 		if err = CopyContents(dstPath, path); err != nil {
 			return
 		}
+		copied++
+	}
+
+	if copied == 0 {
+		err = fmt.Errorf("No VM file found in source artifact")
 	}
 
 	return

post-processor/vagrant/post-processor_test.go

@@ -7,7 +7,9 @@ import (
 	"bytes"
 	"compress/flate"
 	"context"
+	"fmt"
 	"io/ioutil"
+	"math/rand"
 	"os"
 	"runtime"
 	"strings"
@@ -231,9 +233,48 @@ func TestPostProcessorPostProcess_badId(t *testing.T) {
 	}
 }
 
+// mockParallelsVMDir creates a fake temp dir for parallels testing
+//
+// Note: the path to the pvm/macvm dir is returned, the responsibility to remove
+// it befalls the caller.
+func mockParallelsVMDir() ([]string, error) {
+	tmpDir := fmt.Sprintf("%s/%d.pvm", os.TempDir(), rand.Uint32())
+	err := os.MkdirAll(tmpDir, 0755)
+	if err != nil {
+		return nil, err
+	}
+
+	file1, err := os.CreateTemp(tmpDir, "")
+	if err != nil {
+		os.RemoveAll(tmpDir)
+		return nil, err
+	}
+	file1.Close()
+
+	file2, err := os.CreateTemp(tmpDir, "")
+	if err != nil {
+		os.RemoveAll(tmpDir)
+		return nil, err
+	}
+	file2.Close()
+
+	return []string{
+		tmpDir,
+		file1.Name(),
+		file2.Name(),
+	}, nil
+}
+
 func TestPostProcessorPostProcess_vagrantfileUserVariable(t *testing.T) {
 	var p PostProcessor
 
+	inputVM, err := mockParallelsVMDir()
+	if err != nil {
+		t.Fatalf("failed to create parallels VM directory")
+	}
+	dir := inputVM[0]
+	defer os.RemoveAll(dir)
+
 	f, err := ioutil.TempFile("", "packer")
 	if err != nil {
 		t.Fatalf("err: %s", err)
@@ -254,6 +295,7 @@ func TestPostProcessorPostProcess_vagrantfileUserVariable(t *testing.T) {
 
 	a := &packersdk.MockArtifact{
 		BuilderIdValue: "packer.parallels",
+		FilesValue:     inputVM,
 	}
 	a2, _, _, err := p.PostProcess(context.Background(), testUi(), a)
 	if a2 != nil {
@@ -266,6 +308,30 @@ func TestPostProcessorPostProcess_vagrantfileUserVariable(t *testing.T) {
 	}
 }
 
+func TestPostProcessorPostProcess_parallels_no_file(t *testing.T) {
+	var p PostProcessor
+
+	c := map[string]interface{}{}
+	err := p.Configure(c)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	a := &packersdk.MockArtifact{
+		BuilderIdValue: "packer.parallels",
+	}
+	a2, _, _, err := p.PostProcess(context.Background(), testUi(), a)
+	if a2 != nil {
+		for _, fn := range a2.Files() {
+			defer os.Remove(fn)
+		}
+	}
+	if err == nil {
+		t.Fatalf("should have failed without a file to copy, succeeded instead")
+	}
+	t.Logf("failed as expected: %s", err)
+}
+
 func TestProviderForName(t *testing.T) {
 	if v, ok := providerForName("virtualbox").(*VBoxProvider); !ok {
 		t.Fatalf("bad: %#v", v)