Support an array value in the config file (#303)

cmd/cmd.go

@@ -377,6 +377,20 @@ func (o *options) overrideFlagSetDefaultFromConfig(fs *pflag.FlagSet) error {
 			continue
 		}
 
+		if valueSlice, ok := value.([]any); ok {
+			// the value is an array
+			if flagSlice, ok := flag.Value.(pflag.SliceValue); ok {
+				values := make([]string, len(valueSlice))
+				for i, v := range valueSlice {
+					values[i] = fmt.Sprint(v)
+				}
+				if err := flagSlice.Replace(values); err != nil {
+					return fmt.Errorf("invalid value %q for %q in the config file: %v", value, name, err)
+				}
+				continue
+			}
+		}
+
 		if err := flag.Value.Set(fmt.Sprint(value)); err != nil {
 			return fmt.Errorf("invalid value %q for %q in the config file: %v", value, name, err)
 		}

cmd/cmd_test.go

@@ -920,3 +920,46 @@ func TestOptionsOverrideFlagSetDefaultFromConfig(t *testing.T) {
 		})
 	}
 }
+
+func TestOptionsOverrideFlagSetDefaultFromConfigArray(t *testing.T) {
+	tests := []struct {
+		config string
+		want   []string
+	}{
+		{
+			config: "testdata/config-string.yaml",
+			want:   []string{"hello-world"},
+		},
+		{
+			config: "testdata/config-array0.yaml",
+			want:   []string{},
+		},
+		{
+			config: "testdata/config-array1.yaml",
+			want:   []string{"abcd"},
+		},
+		{
+			config: "testdata/config-array2.yaml",
+			want:   []string{"abcd", "efgh"},
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.config, func(t *testing.T) {
+			o := NewOptions(genericclioptions.NewTestIOStreamsDiscard())
+			fs := pflag.NewFlagSet("", pflag.ExitOnError)
+			o.AddFlags(fs)
+			if err := fs.Parse([]string{"--config=" + tt.config}); err != nil {
+				t.Fatal(err)
+			}
+			if err := o.overrideFlagSetDefaultFromConfig(fs); err != nil {
+				t.Fatal(err)
+			}
+			if !reflect.DeepEqual(tt.want, o.exclude) {
+				t.Errorf("expected %v, but got %v", tt.want, o.exclude)
+			}
+		})
+	}
+
+}

cmd/testdata/config-array0.yaml

@@ -0,0 +1 @@
+exclude: []

cmd/testdata/config-array1.yaml

@@ -0,0 +1 @@
+exclude: ["abcd"]

cmd/testdata/config-array2.yaml

@@ -0,0 +1 @@
+exclude: ["abcd", "efgh"]

cmd/testdata/config-string.yaml

@@ -0,0 +1 @@
+exclude: "hello-world"