Fix file creation for output options (#875)

syft/sbom/multi_writer.go

@@ -6,8 +6,8 @@ import (
 	"path"
 
 	"github.com/anchore/syft/internal/log"
-
 	"github.com/hashicorp/go-multierror"
+	"github.com/mitchellh/go-homedir"
 )
 
 // multiWriter holds a list of child sbom.Writers to apply all Write and Close operations to
@@ -21,8 +21,21 @@ type WriterOption struct {
 	Path   string
 }
 
+func NewWriterOption(f Format, p string) WriterOption {
+	expandedPath, err := homedir.Expand(p)
+	if err != nil {
+		log.Warnf("could not expand given writer output path=%q: %w", p, err)
+		// ignore errors
+		expandedPath = p
+	}
+	return WriterOption{
+		Format: f,
+		Path:   expandedPath,
+	}
+}
+
 // NewWriter create all report writers from input options; if a file is not specified, os.Stdout is used
-func NewWriter(options ...WriterOption) (Writer, error) {
+func NewWriter(options ...WriterOption) (_ Writer, err error) {
 	if len(options) == 0 {
 		return nil, fmt.Errorf("no output options provided")
 	}
@@ -30,9 +43,11 @@ func NewWriter(options ...WriterOption) (Writer, error) {
 	out := &multiWriter{}
 
 	defer func() {
-		// close any previously opened files; we can't really recover from any errors
-		if err := out.Close(); err != nil {
-			log.Warnf("unable to close sbom writers: %+v", err)
+		if err != nil {
+			// close any previously opened files; we can't really recover from any errors
+			if err := out.Close(); err != nil {
+				log.Warnf("unable to close sbom writers: %+v", err)
+			}
 		}
 	}()
 

syft/sbom/multi_writer_test.go

@@ -2,9 +2,11 @@ package sbom
 
 import (
 	"io"
+	"path/filepath"
 	"strings"
 	"testing"
 
+	"github.com/docker/docker/pkg/homedir"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -170,3 +172,33 @@ func TestOutputWriter(t *testing.T) {
 		})
 	}
 }
+
+func TestNewWriterOption(t *testing.T) {
+	tests := []struct {
+		name     string
+		path     string
+		expected string
+	}{
+		{
+			name:     "expand home dir",
+			path:     "~/place.txt",
+			expected: filepath.Join(homedir.Get(), "place.txt"),
+		},
+		{
+			name:     "passthrough other paths",
+			path:     "/other/place.txt",
+			expected: "/other/place.txt",
+		},
+		{
+			name:     "no path",
+			path:     "",
+			expected: "",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			o := NewWriterOption(dummyFormat("table"), tt.path)
+			assert.Equal(t, tt.expected, o.Path)
+		})
+	}
+}