src/bootstrap/format.rs

   1 //! Runs rustfmt on the repository.
   2
   3 use crate::builder::Builder;
   4 use crate::util::{output, t};
   5 use ignore::WalkBuilder;
   6 use std::collections::VecDeque;
   7 use std::path::{Path, PathBuf};
   8 use std::process::{Command, Stdio};
   9 use std::sync::mpsc::SyncSender;
  10
  11 fn rustfmt(src: &Path, rustfmt: &Path, paths: &[PathBuf], check: bool) -> impl FnMut() {
  12     let mut cmd = Command::new(&rustfmt);
  13     // avoid the submodule config paths from coming into play,
  14     // we only allow a single global config for the workspace for now
  15     cmd.arg("--config-path").arg(&src.canonicalize().unwrap());
  16     cmd.arg("--edition").arg("2021");
  17     cmd.arg("--unstable-features");
  18     cmd.arg("--skip-children");
  19     if check {
  20         cmd.arg("--check");
  21     }
  22     cmd.args(paths);
  23     let cmd_debug = format!("{:?}", cmd);
  24     let mut cmd = cmd.spawn().expect("running rustfmt");
  25     // poor man's async: return a closure that'll wait for rustfmt's completion
  26     move || {
  27         let status = cmd.wait().unwrap();
  28         if !status.success() {
  29             eprintln!(
  30                 "Running `{}` failed.\nIf you're running `tidy`, \
  31                         try again with `--bless`. Or, if you just want to format \
  32                         code, run `./x.py fmt` instead.",
  33                 cmd_debug,
  34             );
  35             std::process::exit(1);
  36         }
  37     }
  38 }
  39
  40 #[derive(serde::Deserialize)]
  41 struct RustfmtConfig {
  42     ignore: Vec<String>,
  43 }
  44
  45 pub fn format(build: &Builder<'_>, check: bool, paths: &[PathBuf]) {
  46     if build.config.dry_run {
  47         return;
  48     }
  49     let mut builder = ignore::types::TypesBuilder::new();
  50     builder.add_defaults();
  51     builder.select("rust");
  52     let matcher = builder.build().unwrap();
  53     let rustfmt_config = build.src.join("rustfmt.toml");
  54     if !rustfmt_config.exists() {
  55         eprintln!("Not running formatting checks; rustfmt.toml does not exist.");
  56         eprintln!("This may happen in distributed tarballs.");
  57         return;
  58     }
  59     let rustfmt_config = t!(std::fs::read_to_string(&rustfmt_config));
  60     let rustfmt_config: RustfmtConfig = t!(toml::from_str(&rustfmt_config));
  61     let mut ignore_fmt = ignore::overrides::OverrideBuilder::new(&build.src);
  62     for ignore in rustfmt_config.ignore {
  63         ignore_fmt.add(&format!("!{}", ignore)).expect(&ignore);
  64     }
  65     let git_available = match Command::new("git")
  66         .arg("--version")
  67         .stdout(Stdio::null())
  68         .stderr(Stdio::null())
  69         .status()
  70     {
  71         Ok(status) => status.success(),
  72         Err(_) => false,
  73     };
  74     if git_available {
  75         let in_working_tree = match Command::new("git")
  76             .arg("rev-parse")
  77             .arg("--is-inside-work-tree")
  78             .stdout(Stdio::null())
  79             .stderr(Stdio::null())
  80             .status()
  81         {
  82             Ok(status) => status.success(),
  83             Err(_) => false,
  84         };
  85         if in_working_tree {
  86             let untracked_paths_output = output(
  87                 Command::new("git")
  88                     .arg("status")
  89                     .arg("--porcelain")
  90                     .arg("--untracked-files=normal"),
  91             );
  92             let untracked_paths = untracked_paths_output
  93                 .lines()
  94                 .filter(|entry| entry.starts_with("??"))
  95                 .map(|entry| {
  96                     entry.split(' ').nth(1).expect("every git status entry should list a path")
  97                 });
  98             for untracked_path in untracked_paths {
  99                 println!("skip untracked path {} during rustfmt invocations", untracked_path);
 100                 // The leading `/` makes it an exact match against the
 101                 // repository root, rather than a glob. Without that, if you
 102                 // have `foo.rs` in the repository root it will also match
 103                 // against anything like `compiler/rustc_foo/src/foo.rs`,
 104                 // preventing the latter from being formatted.
 105                 ignore_fmt.add(&format!("!/{}", untracked_path)).expect(&untracked_path);
 106             }
 107         } else {
 108             println!("Not in git tree. Skipping git-aware format checks");
 109         }
 110     } else {
 111         println!("Could not find usable git. Skipping git-aware format checks");
 112     }
 113     let ignore_fmt = ignore_fmt.build().unwrap();
 114
 115     let rustfmt_path = build.initial_rustfmt().unwrap_or_else(|| {
 116         eprintln!("./x.py fmt is not supported on this channel");
 117         std::process::exit(1);
 118     });
 119     assert!(rustfmt_path.exists(), "{}", rustfmt_path.display());
 120     let src = build.src.clone();
 121     let (tx, rx): (SyncSender<PathBuf>, _) = std::sync::mpsc::sync_channel(128);
 122     let walker = match paths.get(0) {
 123         Some(first) => {
 124             let mut walker = WalkBuilder::new(first);
 125             for path in &paths[1..] {
 126                 walker.add(path);
 127             }
 128             walker
 129         }
 130         None => WalkBuilder::new(src.clone()),
 131     }
 132     .types(matcher)
 133     .overrides(ignore_fmt)
 134     .build_parallel();
 135
 136     // there is a lot of blocking involved in spawning a child process and reading files to format.
 137     // spawn more processes than available concurrency to keep the CPU busy
 138     let max_processes = build.jobs() as usize * 2;
 139
 140     // spawn child processes on a separate thread so we can batch entries we have received from ignore
 141     let thread = std::thread::spawn(move || {
 142         let mut children = VecDeque::new();
 143         while let Ok(path) = rx.recv() {
 144             // try getting a few more paths from the channel to amortize the overhead of spawning processes
 145             let paths: Vec<_> = rx.try_iter().take(7).chain(std::iter::once(path)).collect();
 146
 147             let child = rustfmt(&src, &rustfmt_path, paths.as_slice(), check);
 148             children.push_back(child);
 149
 150             if children.len() >= max_processes {
 151                 // await oldest child
 152                 children.pop_front().unwrap()();
 153             }
 154         }
 155
 156         // await remaining children
 157         for mut child in children {
 158             child();
 159         }
 160     });
 161
 162     walker.run(|| {
 163         let tx = tx.clone();
 164         Box::new(move |entry| {
 165             let entry = t!(entry);
 166             if entry.file_type().map_or(false, |t| t.is_file()) {
 167                 t!(tx.send(entry.into_path()));
 168             }
 169             ignore::WalkState::Continue
 170         })
 171     });
 172
 173     drop(tx);
 174
 175     thread.join().unwrap();
 176 }