Remove special cases for setup subcommand

- Remove setup special-casing in Flags::parse

src/bootstrap/builder.rs

@@ -19,6 +19,7 @@
 use crate::install;
 use crate::native;
 use crate::run;
+use crate::setup;
 use crate::test;
 use crate::tool::{self, SourceType};
 use crate::util::{self, add_dylib_path, add_link_lib_path, exe, libdir, output, t};
@@ -433,8 +434,11 @@ pub(crate) fn crates(mut self, crates: Vec<&Crate>) -> Self {
 
     // single alias, which does not correspond to any on-disk path
     pub fn alias(mut self, alias: &str) -> Self {
+        // exceptional case for `Kind::Setup` because its `library`
+        // and `compiler` options would otherwise naively match with
+        // `compiler` and `library` folders respectively.
         assert!(
-            !self.builder.src.join(alias).exists(),
+            self.kind == Kind::Setup || !self.builder.src.join(alias).exists(),
             "use `builder.path()` for real paths: {}",
             alias
         );
@@ -757,8 +761,9 @@ macro_rules! describe {
                 run::CollectLicenseMetadata,
                 run::GenerateCopyright,
             ),
+            Kind::Setup => describe!(setup::Profile),
             // These commands either don't use paths, or they're special-cased in Build::build()
-            Kind::Clean | Kind::Format | Kind::Setup => vec![],
+            Kind::Clean | Kind::Format => vec![],
         }
     }
 
@@ -821,7 +826,11 @@ pub fn new(build: &Build) -> Builder<'_> {
             Subcommand::Install { ref paths } => (Kind::Install, &paths[..]),
             Subcommand::Run { ref paths, .. } => (Kind::Run, &paths[..]),
             Subcommand::Format { .. } => (Kind::Format, &[][..]),
-            Subcommand::Clean { .. } | Subcommand::Setup { .. } => {
+            Subcommand::Setup { profile: ref path } => (
+                Kind::Setup,
+                path.as_ref().map_or([].as_slice(), |path| std::slice::from_ref(path)),
+            ),
+            Subcommand::Clean { .. } => {
                 panic!()
             }
         };

src/bootstrap/flags.rs

@@ -143,7 +143,7 @@ pub enum Subcommand {
         args: Vec<String>,
     },
     Setup {
-        profile: Option<Profile>,
+        profile: Option<PathBuf>,
     },
 }
 
@@ -351,7 +351,7 @@ pub fn parse(args: &[String]) -> Flags {
 
         // fn usage()
         let usage = |exit_code: i32, opts: &Options, verbose: bool, subcommand_help: &str| -> ! {
-            let config = Config::parse(&["build".to_string()]);
+            let config = Config::parse(&["setup".to_string()]);
             let build = Build::new(config);
             let paths = Builder::get_help(&build, subcommand);
 
@@ -621,7 +621,7 @@ pub fn parse(args: &[String]) -> Flags {
             }
             Kind::Setup => {
                 let profile = if paths.len() > 1 {
-                    println!("\nat most one profile can be passed to setup\n");
+                    eprintln!("\nerror: At most one profile can be passed to setup\n");
                     usage(1, &opts, verbose, &subcommand_help)
                 } else if let Some(path) = paths.pop() {
                     let profile_string = t!(path.into_os_string().into_string().map_err(

src/bootstrap/lib.rs

@@ -713,10 +713,6 @@ pub fn build(&mut self) {
             return clean::clean(self, all);
         }
 
-        if let Subcommand::Setup { profile } = &self.config.cmd {
-            return setup::setup(&self.config, *profile);
-        }
-
         // Download rustfmt early so that it can be used in rust-analyzer configs.
         let _ = &builder::Builder::new(&self).initial_rustfmt();
 

src/bootstrap/setup.rs

@@ -1,3 +1,4 @@
+use crate::builder::{Builder, RunConfig, ShouldRun, Step};
 use crate::Config;
 use crate::{t, VERSION};
 use std::env::consts::EXE_SUFFIX;
@@ -9,7 +10,7 @@
 use std::str::FromStr;
 use std::{fmt, fs, io};
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
 pub enum Profile {
     Compiler,
     Codegen,
@@ -48,6 +49,16 @@ pub fn all_for_help(indent: &str) -> String {
         }
         out
     }
+
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Profile::Compiler => "compiler",
+            Profile::Codegen => "codegen",
+            Profile::Library => "library",
+            Profile::Tools => "tools",
+            Profile::User => "user",
+        }
+    }
 }
 
 impl FromStr for Profile {
@@ -69,24 +80,58 @@ fn from_str(s: &str) -> Result<Self, Self::Err> {
 
 impl fmt::Display for Profile {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Profile::Compiler => write!(f, "compiler"),
-            Profile::Codegen => write!(f, "codegen"),
-            Profile::Library => write!(f, "library"),
-            Profile::User => write!(f, "user"),
-            Profile::Tools => write!(f, "tools"),
-        }
+        f.write_str(self.as_str())
     }
 }
 
-pub fn setup(config: &Config, profile: Option<Profile>) {
-    let profile = profile.unwrap_or_else(|| t!(interactive_path()));
+impl Step for Profile {
+    type Output = ();
+    const DEFAULT: bool = true;
+
+    fn should_run(mut run: ShouldRun<'_>) -> ShouldRun<'_> {
+        for choice in Profile::all() {
+            run = run.alias(choice.as_str());
+        }
+        run
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        // for Profile, `run.paths` will have 1 and only 1 element
+        // this is because we only accept at most 1 path from user input.
+        // If user calls `x.py setup` without arguments, the interactive TUI
+        // will guide user to provide one.
+        let profile = if run.paths.len() > 1 {
+            // HACK: `builder` runs this step with all paths if no path was passed.
+            t!(interactive_path())
+        } else {
+            run.paths
+                .first()
+                .unwrap()
+                .assert_single_path()
+                .path
+                .as_path()
+                .as_os_str()
+                .to_str()
+                .unwrap()
+                .parse()
+                .unwrap()
+        };
+
+        run.builder.ensure(profile);
+    }
+
+    fn run(self, builder: &Builder<'_>) {
+        setup(&builder.build.config, self)
+    }
+}
+
+pub fn setup(config: &Config, profile: Profile) {
     let stage_path =
         ["build", config.build.rustc_target_arg(), "stage1"].join(&MAIN_SEPARATOR.to_string());
 
     if !rustup_installed() && profile != Profile::User {
         eprintln!("`rustup` is not installed; cannot link `stage1` toolchain");
-    } else if stage_dir_exists(&stage_path[..]) {
+    } else if stage_dir_exists(&stage_path[..]) && !config.dry_run() {
         attempt_toolchain_link(&stage_path[..]);
     }
 
@@ -104,7 +149,9 @@ pub fn setup(config: &Config, profile: Option<Profile>) {
         Profile::User => &["dist", "build"],
     };
 
-    t!(install_git_hook_maybe(&config));
+    if !config.dry_run() {
+        t!(install_git_hook_maybe(&config));
+    }
 
     println!();
 
@@ -144,6 +191,7 @@ fn setup_config_toml(path: &PathBuf, profile: Profile, config: &Config) {
     changelog-seen = {}\n",
         profile, VERSION
     );
+
     t!(fs::write(path, settings));
 
     let include_path = profile.include_path(&config.src);