fix: nil check for config output (#390)

config/api.go

@@ -76,6 +76,9 @@ type Output struct {
 // EffectivePaths returns a slice of effective configured output paths, whether
 // a single or multiple output paths have been configured.
 func (o *Output) ResolvePaths() []string {
+	if o == nil {
+		return []string{}
+	}
 	if o.Path != "" {
 		return []string{o.Path}
 	}

config/api_test.go

@@ -0,0 +1,45 @@
+package config_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/snyk/vervet/v8/config"
+)
+
+func TestOutput_ResolvePaths(t *testing.T) {
+	tests := []struct {
+		name    string
+		subject *config.Output
+		want    []string
+	}{
+		{
+			name:    "nil",
+			subject: nil,
+			want:    []string{},
+		},
+		{
+			name: "returns path if exists",
+			subject: &config.Output{
+				Path:  "path",
+				Paths: []string{"path1", "path2"},
+			},
+			want: []string{"path"},
+		},
+		{
+			name: "return paths if path is empty",
+			subject: &config.Output{
+				Path:  "",
+				Paths: []string{"path1", "path2"},
+			},
+			want: []string{"path1", "path2"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.subject.ResolvePaths(); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("ResolvePaths() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/cmd/backstage.go

@@ -191,6 +191,10 @@ func processCatalog(ctx *cli.Context, w io.Writer) error {
 	for _, apiName := range apiNames {
 		apiConf := proj.APIs[apiName]
 		outputPaths := apiConf.Output.ResolvePaths()
+		if len(outputPaths) == 0 {
+			log.Printf("API %q has no output paths, this command will have no effect", apiName)
+			continue
+		}
 		for _, outputPath := range outputPaths {
 			outputPath = filepath.Join(projectDir, outputPath)
 			if matchPath(outputPath) {