fix: handle running inside a snap (#527)

* fix: handle running inside a snap

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

* test: fixes

* docs: improve error message

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>
Co-authored-by: bashbunni <bunni@bashbunni.dev>

config_cmd.go

@@ -23,13 +23,14 @@ pager: false
 width: 80`
 
 var configCmd = &cobra.Command{
-	Use:     "config",
-	Hidden:  false,
-	Short:   "Edit the glow config file",
-	Long:    paragraph(fmt.Sprintf("\n%s the glow config file. We’ll use EDITOR to determine which editor to use. If the config file doesn't exist, it will be created.", keyword("Edit"))),
-	Example: paragraph("glow config\nglow config --config path/to/config.yml"),
-	Args:    cobra.NoArgs,
-	RunE: func(cmd *cobra.Command, args []string) error {
+	Use:          "config",
+	Hidden:       false,
+	Short:        "Edit the glow config file",
+	Long:         paragraph(fmt.Sprintf("\n%s the glow config file. We’ll use EDITOR to determine which editor to use. If the config file doesn't exist, it will be created.", keyword("Edit"))),
+	Example:      paragraph("glow config\nglow config --config path/to/config.yml"),
+	Args:         cobra.NoArgs,
+	SilenceUsage: true,
+	RunE: func(_ *cobra.Command, _ []string) error {
 		if configFile == "" {
 			scope := gap.NewScope(gap.User, "glow")
 
@@ -64,7 +65,10 @@ var configCmd = &cobra.Command{
 			return err
 		}
 
-		c := editor.Cmd(configFile)
+		c, err := editor.Cmd(configFile)
+		if err != nil {
+			return fmt.Errorf("could not edit %s: %w", configFile, err)
+		}
 		c.Stdin = os.Stdin
 		c.Stdout = os.Stdout
 		c.Stderr = os.Stderr

editor/editor.go

@@ -1,6 +1,7 @@
 package editor
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
 	"strings"
@@ -10,9 +11,12 @@ const defaultEditor = "nano"
 
 // Cmd returns a *exec.Cmd editing the given path with $EDITOR or nano if no
 // $EDITOR is set.
-func Cmd(path string) *exec.Cmd {
+func Cmd(path string) (*exec.Cmd, error) {
+	if os.Getenv("SNAP_REVISION") != "" {
+		return nil, fmt.Errorf("Did you install with Snap? Glow is sandboxed and unable to open an editor. Please install Glow with Go or another package manager to enable editing.")
+	}
 	editor, args := getEditor()
-	return exec.Command(editor, append(args, path)...)
+	return exec.Command(editor, append(args, path)...), nil
 }
 
 func getEditor() (string, []string) {

editor/editor_test.go

@@ -16,11 +16,22 @@ func TestEditor(t *testing.T) {
 	} {
 		t.Run(k, func(t *testing.T) {
 			t.Setenv("EDITOR", k)
-			cmd := Cmd("README.md")
+			cmd, _ := Cmd("README.md")
 			got := cmd.Args
 			if !reflect.DeepEqual(got, v) {
 				t.Fatalf("expected %v; got %v", v, got)
 			}
 		})
 	}
+
+	t.Run("inside snap", func(t *testing.T) {
+		t.Setenv("SNAP_REVISION", "10")
+		got, err := Cmd("foo")
+		if err == nil {
+			t.Fatalf("expected an error, got nil")
+		}
+		if got != nil {
+			t.Fatalf("should have returned nil, got %v", got)
+		}
+	})
 }

ui/editor.go

@@ -11,5 +11,12 @@ func openEditor(path string) tea.Cmd {
 	cb := func(err error) tea.Msg {
 		return editorFinishedMsg{err}
 	}
-	return tea.ExecProcess(editor.Cmd(path), cb)
+
+	editor, err := editor.Cmd(path)
+	if err != nil {
+		return func() tea.Msg {
+			return errMsg{err}
+		}
+	}
+	return tea.ExecProcess(editor, cb)
 }