cli: improve dbus error messaging on linux

Fixes https://github.com/microsoft/vscode-remote-release/issues/7778

cli/src/util/errors.rs

@@ -442,6 +442,26 @@ macro_rules! makeAnyError {
     };
 }
 
+#[derive(Debug)]
+pub struct DbusConnectFailedError(pub String);
+
+impl Display for DbusConnectFailedError {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		let mut str = String::new();
+		str.push_str("Error creating dbus session. This command uses systemd for managing services, you should check that systemd is installed and under your user.");
+
+		if std::env::var("WSL_DISTRO_NAME").is_ok() {
+			str.push_str("\n\nTo enable systemd on WSL, check out: https://devblogs.microsoft.com/commandline/systemd-support-is-now-available-in-wsl/.\n\n");
+		}
+
+		str.push_str("If running `systemctl status` works, systemd is ok, but your session dbus may not be. You might need to:\n\n- Install the `dbus-user-session` package, and reboot if it was not installed\n- Start the user dbus session with `systemctl --user enable dbus --now`.\n\nThe error encountered was: ");
+		str.push_str(&self.0);
+		str.push('\n');
+
+		write!(f, "{}", str)
+	}
+}
+
 /// Internal errors in the VS Code CLI.
 /// Note: other error should be migrated to this type gradually
 #[derive(Error, Debug)]
@@ -522,7 +542,8 @@ makeAnyError!(
 	MissingHomeDirectory,
 	OAuthError,
 	InvalidRpcDataError,
-	CodeError
+	CodeError,
+	DbusConnectFailedError
 );
 
 impl From<reqwest::Error> for AnyError {