3 files changed, 86 insertions, 65 deletions

diff --git a/xtask/src/ast_src.rs b/xtask/src/ast_src.rs
index 9c02f7c6f..98c8644e4 100644
--- a/xtask/src/ast_src.rs
+++ b/xtask/src/ast_src.rs
@@ -595,7 +595,7 @@ pub(crate) const AST_SRC: AstSrc = AstSrc {
             qualifier: Path,
         }
         struct PathSegment {
-            T![::], T![<], NameRef, TypeArgList, ParamList, RetType, PathType, T![>]
+            T![::], T![crate], T![<], NameRef, TypeArgList, ParamList, RetType, PathType, T![>]
         }
         struct TypeArgList {
             T![::],
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index ec824a518..2b7a461e5 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -10,23 +10,19 @@ pub mod pre_commit;
 pub mod codegen;
 mod ast_src;
 
-use anyhow::Context;
 use std::{
     env,
-    io::Write,
     path::{Path, PathBuf},
-    process::{Command, Stdio},
 };
+
 use walkdir::{DirEntry, WalkDir};
 
 use crate::{
     codegen::Mode,
-    not_bash::{date_iso, fs2, pushd, rm_rf, run},
+    not_bash::{date_iso, fs2, pushd, pushenv, rm_rf, run},
 };
 
-pub use anyhow::Result;
-
-const TOOLCHAIN: &str = "stable";
+pub use anyhow::{bail, Context as _, Result};
 
 pub fn project_root() -> PathBuf {
     Path::new(
@@ -55,54 +51,44 @@ pub fn rust_files(path: &Path) -> impl Iterator<Item = PathBuf> {
 
 pub fn run_rustfmt(mode: Mode) -> Result<()> {
     let _dir = pushd(project_root());
+    let _e = pushenv("RUSTUP_TOOLCHAIN", "stable");
     ensure_rustfmt()?;
-
-    let check = if mode == Mode::Verify { "--check" } else { "" };
-    run!("rustup run {} -- cargo fmt -- {}", TOOLCHAIN, check)?;
+    match mode {
+        Mode::Overwrite => run!("cargo fmt"),
+        Mode::Verify => run!("cargo fmt -- --check"),
+    }?;
     Ok(())
 }
 
 fn reformat(text: impl std::fmt::Display) -> Result<String> {
+    let _e = pushenv("RUSTUP_TOOLCHAIN", "stable");
     ensure_rustfmt()?;
-    let mut rustfmt = Command::new("rustup")
-        .args(&["run", TOOLCHAIN, "--", "rustfmt", "--config-path"])
-        .arg(project_root().join("rustfmt.toml"))
-        .args(&["--config", "fn_single_line=true"])
-        .stdin(Stdio::piped())
-        .stdout(Stdio::piped())
-        .spawn()?;
-    write!(rustfmt.stdin.take().unwrap(), "{}", text)?;
-    let output = rustfmt.wait_with_output()?;
-    let stdout = String::from_utf8(output.stdout)?;
+    let stdout = run!(
+        "rustfmt --config-path {} --config fn_single_line=true", project_root().join("rustfmt.toml").display();
+        <text.to_string().as_bytes()
+    )?;
     let preamble = "Generated file, do not edit by hand, see `xtask/src/codegen`";
-    Ok(format!("//! {}\n\n{}", preamble, stdout))
+    Ok(format!("//! {}\n\n{}\n", preamble, stdout))
 }
 
 fn ensure_rustfmt() -> Result<()> {
-    match Command::new("rustup")
-        .args(&["run", TOOLCHAIN, "--", "cargo", "fmt", "--version"])
-        .stderr(Stdio::null())
-        .stdout(Stdio::null())
-        .status()
-    {
-        Ok(status) if status.success() => return Ok(()),
-        _ => (),
-    };
-    run!("rustup toolchain install {}", TOOLCHAIN)?;
-    run!("rustup component add rustfmt --toolchain {}", TOOLCHAIN)?;
+    let out = run!("rustfmt --version")?;
+    if !out.contains("stable") {
+        bail!(
+            "Failed to run rustfmt from toolchain 'stable'. \
+             Please run `rustup component add rustfmt --toolchain stable` to install it.",
+        )
+    }
     Ok(())
 }
 
 pub fn run_clippy() -> Result<()> {
-    match Command::new("rustup")
-        .args(&["run", TOOLCHAIN, "--", "cargo", "clippy", "--version"])
-        .stderr(Stdio::null())
-        .stdout(Stdio::null())
-        .status()
-    {
-        Ok(status) if status.success() => (),
-        _ => install_clippy().context("install clippy")?,
-    };
+    if run!("cargo clippy --version").is_err() {
+        bail!(
+            "Failed run cargo clippy. \
+            Please run `rustup component add clippy` to install it.",
+        )
+    }
 
     let allowed_lints = [
         "clippy::collapsible_if",
@@ -110,27 +96,24 @@ pub fn run_clippy() -> Result<()> {
         "clippy::nonminimal_bool",
         "clippy::redundant_pattern_matching",
     ];
-    run!(
-        "rustup run {} -- cargo clippy --all-features --all-targets -- -A {}",
-        TOOLCHAIN,
-        allowed_lints.join(" -A ")
-    )?;
-    Ok(())
-}
-
-fn install_clippy() -> Result<()> {
-    run!("rustup toolchain install {}", TOOLCHAIN)?;
-    run!("rustup component add clippy --toolchain {}", TOOLCHAIN)?;
+    run!("cargo clippy --all-features --all-targets -- -A {}", allowed_lints.join(" -A "))?;
     Ok(())
 }
 
 pub fn run_fuzzer() -> Result<()> {
     let _d = pushd("./crates/ra_syntax");
+    let _e = pushenv("RUSTUP_TOOLCHAIN", "nightly");
     if run!("cargo fuzz --help").is_err() {
         run!("cargo install cargo-fuzz")?;
     };
 
-    run!("rustup run nightly -- cargo fuzz run parser")?;
+    // Expecting nightly rustc
+    let out = run!("rustc --version")?;
+    if !out.contains("nightly") {
+        bail!("fuzz tests require nightly rustc")
+    }
+
+    run!("cargo fuzz run parser")?;
     Ok(())
 }
 
diff --git a/xtask/src/not_bash.rs b/xtask/src/not_bash.rs
index ef1699934..a6431e586 100644
--- a/xtask/src/not_bash.rs
+++ b/xtask/src/not_bash.rs
@@ -3,6 +3,8 @@
 use std::{
     cell::RefCell,
     env,
+    ffi::OsString,
+    io::Write,
     path::{Path, PathBuf},
     process::{Command, Stdio},
 };
@@ -57,7 +59,10 @@ macro_rules! _run {
         run!($($expr),*; echo = true)
     };
     ($($expr:expr),* ; echo = $echo:expr) => {
-        $crate::not_bash::run_process(format!($($expr),*), $echo)
+        $crate::not_bash::run_process(format!($($expr),*), $echo, None)
+    };
+    ($($expr:expr),* ;  <$stdin:expr) => {
+        $crate::not_bash::run_process(format!($($expr),*), false, Some($stdin))
     };
 }
 pub(crate) use _run as run;
@@ -77,6 +82,21 @@ impl Drop for Pushd {
     }
 }
 
+pub struct Pushenv {
+    _p: (),
+}
+
+pub fn pushenv(var: &str, value: &str) -> Pushenv {
+    Env::with(|env| env.pushenv(var.into(), value.into()));
+    Pushenv { _p: () }
+}
+
+impl Drop for Pushenv {
+    fn drop(&mut self) {
+        Env::with(|env| env.popenv())
+    }
+}
+
 pub fn rm_rf(path: impl AsRef<Path>) -> Result<()> {
     let path = path.as_ref();
     if !path.exists() {
@@ -90,15 +110,15 @@ pub fn rm_rf(path: impl AsRef<Path>) -> Result<()> {
 }
 
 #[doc(hidden)]
-pub fn run_process(cmd: String, echo: bool) -> Result<String> {
-    run_process_inner(&cmd, echo).with_context(|| format!("process `{}` failed", cmd))
+pub fn run_process(cmd: String, echo: bool, stdin: Option<&[u8]>) -> Result<String> {
+    run_process_inner(&cmd, echo, stdin).with_context(|| format!("process `{}` failed", cmd))
 }
 
 pub fn date_iso() -> Result<String> {
     run!("date --iso --utc")
 }
 
-fn run_process_inner(cmd: &str, echo: bool) -> Result<String> {
+fn run_process_inner(cmd: &str, echo: bool, stdin: Option<&[u8]>) -> Result<String> {
     let mut args = shelx(cmd);
     let binary = args.remove(0);
     let current_dir = Env::with(|it| it.cwd().to_path_buf());
@@ -107,12 +127,17 @@ fn run_process_inner(cmd: &str, echo: bool) -> Result<String> {
         println!("> {}", cmd)
     }
 
-    let output = Command::new(binary)
-        .args(args)
-        .current_dir(current_dir)
-        .stdin(Stdio::null())
-        .stderr(Stdio::inherit())
-        .output()?;
+    let mut command = Command::new(binary);
+    command.args(args).current_dir(current_dir).stderr(Stdio::inherit());
+    let output = match stdin {
+        None => command.stdin(Stdio::null()).output(),
+        Some(stdin) => {
+            command.stdin(Stdio::piped()).stdout(Stdio::piped());
+            let mut process = command.spawn()?;
+            process.stdin.take().unwrap().write_all(stdin)?;
+            process.wait_with_output()
+        }
+    }?;
     let stdout = String::from_utf8(output.stdout)?;
 
     if echo {
@@ -133,13 +158,15 @@ fn shelx(cmd: &str) -> Vec<String> {
 
 struct Env {
     pushd_stack: Vec<PathBuf>,
+    pushenv_stack: Vec<(OsString, Option<OsString>)>,
 }
 
 impl Env {
     fn with<F: FnOnce(&mut Env) -> T, T>(f: F) -> T {
         thread_local! {
             static ENV: RefCell<Env> = RefCell::new(Env {
-                pushd_stack: vec![env::current_dir().unwrap()]
+                pushd_stack: vec![env::current_dir().unwrap()],
+                pushenv_stack: vec![],
             });
         }
         ENV.with(|it| f(&mut *it.borrow_mut()))
@@ -154,6 +181,17 @@ impl Env {
         self.pushd_stack.pop().unwrap();
         env::set_current_dir(self.cwd()).unwrap();
     }
+    fn pushenv(&mut self, var: OsString, value: OsString) {
+        self.pushenv_stack.push((var.clone(), env::var_os(&var)));
+        env::set_var(var, value)
+    }
+    fn popenv(&mut self) {
+        let (var, value) = self.pushenv_stack.pop().unwrap();
+        match value {
+            None => env::remove_var(var),
+            Some(value) => env::set_var(var, value),
+        }
+    }
     fn cwd(&self) -> &Path {
         self.pushd_stack.last().unwrap()
     }