Add support for fish shell

src/cli/self_update/env.fish

@@ -0,0 +1,5 @@
+# rustup shell setup
+if not contains "{cargo_bin}" $PATH
+ # Prepending path in case a system-installed rustc needs to be overridden
+ set -x PATH "{cargo_bin}" $PATH
+end

src/cli/self_update/shell.rs

@@ -71,7 +71,12 @@ pub(crate) fn cargo_home_str() -> Result<Cow<'static, str>> {
 // TODO?: Make a decision on Ion Shell, Power Shell, Nushell
 // Cross-platform non-POSIX shells have not been assessed for integration yet
 fn enumerate_shells() -> Vec<Shell> {
- vec![Box::new(Posix), Box::new(Bash), Box::new(Zsh)]
+ vec![
+ Box::new(Posix),
+ Box::new(Bash),
+ Box::new(Zsh),
+ Box::new(Fish),
+ ]
 }
 
 pub(crate) fn get_available_shells() -> impl Iterator<Item = Shell> {
@@ -201,6 +206,48 @@ impl UnixShell for Zsh {
  }
 }
 
+struct Fish;
+
+impl UnixShell for Fish {
+ fn does_exist(&self) -> bool {
+ // fish has to either be the shell or be callable for fish setup.
+ matches!(process().var("SHELL"), Ok(sh) if sh.contains("fish"))
+ || matches!(utils::find_cmd(&["fish"]), Some(_))
+ }
+
+ // > "$XDG_CONFIG_HOME/fish/conf.d" (or "~/.config/fish/conf.d" if that variable is unset) for the user
+ // from <https://github.com/fish-shell/fish-shell/issues/3170#issuecomment-228311857>
+ fn rcfiles(&self) -> Vec<PathBuf> {
+ let p0 = process().var("XDG_CONFIG_HOME").ok().map(|p| {
+ let mut path = PathBuf::from(p);
+ path.push("fish/conf.d/rustup.fish");
+ path
+ });
+
+ let p1 = utils::home_dir().map(|mut path| {
+ path.push(".config/fish/conf.d/rustup.fish");
+ path
+ });
+
+ p0.into_iter().chain(p1).collect()
+ }
+
+ fn update_rcs(&self) -> Vec<PathBuf> {
+ self.rcfiles()
+ }
+
+ fn env_script(&self) -> ShellScript {
+ ShellScript {
+ name: "env.fish",
+ content: include_str!("env.fish"),
+ }
+ }
+
+ fn source_string(&self) -> Result<String> {
+ Ok(format!(r#". "{}/env.fish""#, cargo_home_str()?))
+ }
+}
+
 pub(crate) fn legacy_paths() -> impl Iterator<Item = PathBuf> {
  let zprofiles = Zsh::zdotdir()
  .into_iter()