Fix panic when using diff --exclude

cmd/config.go

@@ -204,6 +204,7 @@ func newConfig(options ...configOption) (*Config, error) {
 		Umask:   chezmoi.Umask,
 		Color:   "auto",
 		Diff: diffCmdConfig{
+			Exclude: chezmoi.NewEntryTypeSet(chezmoi.EntryTypesNone),
 			Pager:   os.Getenv("PAGER"),
 			include: chezmoi.NewEntryTypeSet(chezmoi.EntryTypesAll),
 		},

cmd/diffcmd_test.go

@@ -0,0 +1,104 @@
+package cmd
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/twpayne/go-vfs/v2"
+	"github.com/twpayne/go-vfs/v2/vfst"
+
+	"github.com/twpayne/chezmoi/v2/internal/chezmoitest"
+)
+
+func TestDiffCmd(t *testing.T) {
+	if chezmoitest.Umask != 0o22 {
+		t.Skip("umask not 0o22")
+	}
+	for _, tc := range []struct {
+		name      string
+		extraRoot interface{}
+		args      []string
+		stdoutStr string
+	}{
+		{
+			name: "empty",
+		},
+		{
+			name: "file",
+			extraRoot: map[string]interface{}{
+				"/home/user/.local/share/chezmoi": map[string]interface{}{
+					"dot_file": "# contents of .file\n",
+				},
+			},
+			stdoutStr: chezmoitest.JoinLines(
+				`diff --git a/.file b/.file`,
+				`new file mode 100644`,
+				`index 0000000000000000000000000000000000000000..8a52cb9ce9551221716a53786ad74104c5902362`,
+				`--- /dev/null`,
+				`+++ b/.file`,
+				`@@ -0,0 +1 @@`,
+				`+# contents of .file`,
+			),
+		},
+		{
+			name: "simple_exclude_files",
+			extraRoot: map[string]interface{}{
+				"/home/user/.local/share/chezmoi": map[string]interface{}{
+					"dot_file":            "# contents of .file\n",
+					"symlink_dot_symlink": ".file\n",
+				},
+			},
+			args: []string{
+				"--exclude", "files",
+			},
+			stdoutStr: chezmoitest.JoinLines(
+				`diff --git a/.symlink b/.symlink`,
+				`new file mode 120000`,
+				`index 0000000000000000000000000000000000000000..3e6844d17780d623d817c3e22bcd1128d64422ae`,
+				`--- /dev/null`,
+				`+++ b/.symlink`,
+				`@@ -0,0 +1 @@`,
+				`+.file`,
+			),
+		},
+		{
+			name: "simple_exclude_files_with_config",
+			extraRoot: map[string]interface{}{
+				"/home/user": map[string]interface{}{
+					".config/chezmoi/chezmoi.toml": chezmoitest.JoinLines(
+						`[diff]`,
+						`  exclude = ["files"]`,
+					),
+					".local/share/chezmoi": map[string]interface{}{
+						"dot_file":            "# contents of .file\n",
+						"symlink_dot_symlink": ".file\n",
+					},
+				},
+			},
+			stdoutStr: chezmoitest.JoinLines(
+				`diff --git a/.symlink b/.symlink`,
+				`new file mode 120000`,
+				`index 0000000000000000000000000000000000000000..3e6844d17780d623d817c3e22bcd1128d64422ae`,
+				`--- /dev/null`,
+				`+++ b/.symlink`,
+				`@@ -0,0 +1 @@`,
+				`+.file`,
+			),
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			chezmoitest.WithTestFS(t, map[string]interface{}{
+				"/home/user": &vfst.Dir{Perm: 0o777 &^ chezmoitest.Umask},
+			}, func(fs vfs.FS) {
+				if tc.extraRoot != nil {
+					require.NoError(t, vfst.NewBuilder().Build(fs, tc.extraRoot))
+				}
+				var stdout strings.Builder
+				require.NoError(t, newTestConfig(t, fs, withStdout(&stdout)).execute(append([]string{"diff"}, tc.args...)))
+				assert.Equal(t, tc.stdoutStr, stdout.String())
+			})
+		})
+	}
+}

internal/chezmoi/entrytypeset.go

@@ -192,7 +192,7 @@ func (s *EntryTypeSet) Type() string {
 // from a []string.
 func StringSliceToEntryTypeSetHookFunc() mapstructure.DecodeHookFunc {
 	return func(from, to reflect.Type, data interface{}) (interface{}, error) {
-		if to != reflect.TypeOf(&EntryTypeSet{}) {
+		if to != reflect.TypeOf(EntryTypeSet{}) {
 			return data, nil
 		}
 		sl, ok := data.([]interface{})

testdata/scripts/exclude.txt

@@ -1,5 +1,10 @@
 [!umask:022] skip
 
+# test chezmoi diff --exclude
+chezmoi diff --exclude=scripts
+[!windows] cmp stdout golden/diff-no-scripts
+[windows] cmp stdout golden/diff-no-scripts-windows
+
 # test that chezmoi diff respects the diff.exclude configuration variable
 chezmoi diff
 [!windows] cmp stdout golden/diff