src/tools/clippy/src/driver.rs

   1 #![feature(rustc_private)]
   2 #![feature(once_cell)]
   3 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
   4 // warn on lints, that are included in `rust-lang/rust`s bootstrap
   5 #![warn(rust_2018_idioms, unused_lifetimes)]
   6 // warn on rustc internal lints
   7 #![warn(rustc::internal)]
   8
   9 // FIXME: switch to something more ergonomic here, once available.
  10 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
  11 extern crate rustc_driver;
  12 extern crate rustc_errors;
  13 extern crate rustc_interface;
  14 extern crate rustc_session;
  15 extern crate rustc_span;
  16
  17 use rustc_interface::interface;
  18 use rustc_session::parse::ParseSess;
  19 use rustc_span::symbol::Symbol;
  20 use rustc_tools_util::VersionInfo;
  21
  22 use std::borrow::Cow;
  23 use std::env;
  24 use std::ops::Deref;
  25 use std::panic;
  26 use std::path::{Path, PathBuf};
  27 use std::process::{exit, Command};
  28 use std::sync::LazyLock;
  29
  30 /// If a command-line option matches `find_arg`, then apply the predicate `pred` on its value. If
  31 /// true, then return it. The parameter is assumed to be either `--arg=value` or `--arg value`.
  32 fn arg_value<'a, T: Deref<Target = str>>(
  33     args: &'a [T],
  34     find_arg: &str,
  35     pred: impl Fn(&str) -> bool,
  36 ) -> Option<&'a str> {
  37     let mut args = args.iter().map(Deref::deref);
  38     while let Some(arg) = args.next() {
  39         let mut arg = arg.splitn(2, '=');
  40         if arg.next() != Some(find_arg) {
  41             continue;
  42         }
  43
  44         match arg.next().or_else(|| args.next()) {
  45             Some(v) if pred(v) => return Some(v),
  46             _ => {},
  47         }
  48     }
  49     None
  50 }
  51
  52 #[test]
  53 fn test_arg_value() {
  54     let args = &["--bar=bar", "--foobar", "123", "--foo"];
  55
  56     assert_eq!(arg_value(&[] as &[&str], "--foobar", |_| true), None);
  57     assert_eq!(arg_value(args, "--bar", |_| false), None);
  58     assert_eq!(arg_value(args, "--bar", |_| true), Some("bar"));
  59     assert_eq!(arg_value(args, "--bar", |p| p == "bar"), Some("bar"));
  60     assert_eq!(arg_value(args, "--bar", |p| p == "foo"), None);
  61     assert_eq!(arg_value(args, "--foobar", |p| p == "foo"), None);
  62     assert_eq!(arg_value(args, "--foobar", |p| p == "123"), Some("123"));
  63     assert_eq!(arg_value(args, "--foobar", |p| p.contains("12")), Some("123"));
  64     assert_eq!(arg_value(args, "--foo", |_| true), None);
  65 }
  66
  67 fn track_clippy_args(parse_sess: &mut ParseSess, args_env_var: &Option<String>) {
  68     parse_sess.env_depinfo.get_mut().insert((
  69         Symbol::intern("CLIPPY_ARGS"),
  70         args_env_var.as_deref().map(Symbol::intern),
  71     ));
  72 }
  73
  74 struct DefaultCallbacks;
  75 impl rustc_driver::Callbacks for DefaultCallbacks {}
  76
  77 /// This is different from `DefaultCallbacks` that it will inform Cargo to track the value of
  78 /// `CLIPPY_ARGS` environment variable.
  79 struct RustcCallbacks {
  80     clippy_args_var: Option<String>,
  81 }
  82
  83 impl rustc_driver::Callbacks for RustcCallbacks {
  84     fn config(&mut self, config: &mut interface::Config) {
  85         let clippy_args_var = self.clippy_args_var.take();
  86         config.parse_sess_created = Some(Box::new(move |parse_sess| {
  87             track_clippy_args(parse_sess, &clippy_args_var);
  88         }));
  89     }
  90 }
  91
  92 struct ClippyCallbacks {
  93     clippy_args_var: Option<String>,
  94 }
  95
  96 impl rustc_driver::Callbacks for ClippyCallbacks {
  97     // JUSTIFICATION: necessary in clippy driver to set `mir_opt_level`
  98     #[allow(rustc::bad_opt_access)]
  99     fn config(&mut self, config: &mut interface::Config) {
 100         let previous = config.register_lints.take();
 101         let clippy_args_var = self.clippy_args_var.take();
 102         config.parse_sess_created = Some(Box::new(move |parse_sess| {
 103             track_clippy_args(parse_sess, &clippy_args_var);
 104         }));
 105         config.register_lints = Some(Box::new(move |sess, lint_store| {
 106             // technically we're ~guaranteed that this is none but might as well call anything that
 107             // is there already. Certainly it can't hurt.
 108             if let Some(previous) = &previous {
 109                 (previous)(sess, lint_store);
 110             }
 111
 112             let conf = clippy_lints::read_conf(sess);
 113             clippy_lints::register_plugins(lint_store, sess, &conf);
 114             clippy_lints::register_pre_expansion_lints(lint_store, sess, &conf);
 115             clippy_lints::register_renamed(lint_store);
 116         }));
 117
 118         // FIXME: #4825; This is required, because Clippy lints that are based on MIR have to be
 119         // run on the unoptimized MIR. On the other hand this results in some false negatives. If
 120         // MIR passes can be enabled / disabled separately, we should figure out, what passes to
 121         // use for Clippy.
 122         config.opts.unstable_opts.mir_opt_level = Some(0);
 123     }
 124 }
 125
 126 fn display_help() {
 127     println!(
 128         "\
 129 Checks a package to catch common mistakes and improve your Rust code.
 130
 131 Usage:
 132     cargo clippy [options] [--] [<opts>...]
 133
 134 Common options:
 135     -h, --help               Print this message
 136         --rustc              Pass all args to rustc
 137     -V, --version            Print version info and exit
 138
 139 Other options are the same as `cargo check`.
 140
 141 To allow or deny a lint from the command line you can use `cargo clippy --`
 142 with:
 143
 144     -W --warn OPT       Set lint warnings
 145     -A --allow OPT      Set lint allowed
 146     -D --deny OPT       Set lint denied
 147     -F --forbid OPT     Set lint forbidden
 148
 149 You can use tool lints to allow or deny lints from your code, eg.:
 150
 151     #[allow(clippy::needless_lifetimes)]
 152 "
 153     );
 154 }
 155
 156 const BUG_REPORT_URL: &str = "https://github.com/rust-lang/rust-clippy/issues/new";
 157
 158 type PanicCallback = dyn Fn(&panic::PanicInfo<'_>) + Sync + Send + 'static;
 159 static ICE_HOOK: LazyLock<Box<PanicCallback>> = LazyLock::new(|| {
 160     let hook = panic::take_hook();
 161     panic::set_hook(Box::new(|info| report_clippy_ice(info, BUG_REPORT_URL)));
 162     hook
 163 });
 164
 165 fn report_clippy_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str) {
 166     // Invoke our ICE handler, which prints the actual panic message and optionally a backtrace
 167     (*ICE_HOOK)(info);
 168
 169     // Separate the output with an empty line
 170     eprintln!();
 171
 172     let fallback_bundle = rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
 173     let emitter = Box::new(rustc_errors::emitter::EmitterWriter::stderr(
 174         rustc_errors::ColorConfig::Auto,
 175         None,
 176         None,
 177         fallback_bundle,
 178         false,
 179         false,
 180         None,
 181         false,
 182     ));
 183     let handler = rustc_errors::Handler::with_emitter(true, None, emitter);
 184
 185     // a .span_bug or .bug call has already printed what
 186     // it wants to print.
 187     if !info.payload().is::<rustc_errors::ExplicitBug>() {
 188         let mut d = rustc_errors::Diagnostic::new(rustc_errors::Level::Bug, "unexpected panic");
 189         handler.emit_diagnostic(&mut d);
 190     }
 191
 192     let version_info = rustc_tools_util::get_version_info!();
 193
 194     let xs: Vec<Cow<'static, str>> = vec![
 195         "the compiler unexpectedly panicked. this is a bug.".into(),
 196         format!("we would appreciate a bug report: {}", bug_report_url).into(),
 197         format!("Clippy version: {}", version_info).into(),
 198     ];
 199
 200     for note in &xs {
 201         handler.note_without_error(note.as_ref());
 202     }
 203
 204     // If backtraces are enabled, also print the query stack
 205     let backtrace = env::var_os("RUST_BACKTRACE").map_or(false, |x| &x != "0");
 206
 207     let num_frames = if backtrace { None } else { Some(2) };
 208
 209     interface::try_print_query_stack(&handler, num_frames);
 210 }
 211
 212 fn toolchain_path(home: Option<String>, toolchain: Option<String>) -> Option<PathBuf> {
 213     home.and_then(|home| {
 214         toolchain.map(|toolchain| {
 215             let mut path = PathBuf::from(home);
 216             path.push("toolchains");
 217             path.push(toolchain);
 218             path
 219         })
 220     })
 221 }
 222
 223 #[allow(clippy::too_many_lines)]
 224 pub fn main() {
 225     rustc_driver::init_rustc_env_logger();
 226     LazyLock::force(&ICE_HOOK);
 227     exit(rustc_driver::catch_with_exit_code(move || {
 228         let mut orig_args: Vec<String> = env::args().collect();
 229
 230         // Get the sysroot, looking from most specific to this invocation to the least:
 231         // - command line
 232         // - runtime environment
 233         //    - SYSROOT
 234         //    - RUSTUP_HOME, MULTIRUST_HOME, RUSTUP_TOOLCHAIN, MULTIRUST_TOOLCHAIN
 235         // - sysroot from rustc in the path
 236         // - compile-time environment
 237         //    - SYSROOT
 238         //    - RUSTUP_HOME, MULTIRUST_HOME, RUSTUP_TOOLCHAIN, MULTIRUST_TOOLCHAIN
 239         let sys_root_arg = arg_value(&orig_args, "--sysroot", |_| true);
 240         let have_sys_root_arg = sys_root_arg.is_some();
 241         let sys_root = sys_root_arg
 242             .map(PathBuf::from)
 243             .or_else(|| std::env::var("SYSROOT").ok().map(PathBuf::from))
 244             .or_else(|| {
 245                 let home = std::env::var("RUSTUP_HOME")
 246                     .or_else(|_| std::env::var("MULTIRUST_HOME"))
 247                     .ok();
 248                 let toolchain = std::env::var("RUSTUP_TOOLCHAIN")
 249                     .or_else(|_| std::env::var("MULTIRUST_TOOLCHAIN"))
 250                     .ok();
 251                 toolchain_path(home, toolchain)
 252             })
 253             .or_else(|| {
 254                 Command::new("rustc")
 255                     .arg("--print")
 256                     .arg("sysroot")
 257                     .output()
 258                     .ok()
 259                     .and_then(|out| String::from_utf8(out.stdout).ok())
 260                     .map(|s| PathBuf::from(s.trim()))
 261             })
 262             .or_else(|| option_env!("SYSROOT").map(PathBuf::from))
 263             .or_else(|| {
 264                 let home = option_env!("RUSTUP_HOME")
 265                     .or(option_env!("MULTIRUST_HOME"))
 266                     .map(ToString::to_string);
 267                 let toolchain = option_env!("RUSTUP_TOOLCHAIN")
 268                     .or(option_env!("MULTIRUST_TOOLCHAIN"))
 269                     .map(ToString::to_string);
 270                 toolchain_path(home, toolchain)
 271             })
 272             .map(|pb| pb.to_string_lossy().to_string())
 273             .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust");
 274
 275         // make "clippy-driver --rustc" work like a subcommand that passes further args to "rustc"
 276         // for example `clippy-driver --rustc --version` will print the rustc version that clippy-driver
 277         // uses
 278         if let Some(pos) = orig_args.iter().position(|arg| arg == "--rustc") {
 279             orig_args.remove(pos);
 280             orig_args[0] = "rustc".to_string();
 281
 282             // if we call "rustc", we need to pass --sysroot here as well
 283             let mut args: Vec<String> = orig_args.clone();
 284             if !have_sys_root_arg {
 285                 args.extend(vec!["--sysroot".into(), sys_root]);
 286             };
 287
 288             return rustc_driver::RunCompiler::new(&args, &mut DefaultCallbacks).run();
 289         }
 290
 291         if orig_args.iter().any(|a| a == "--version" || a == "-V") {
 292             let version_info = rustc_tools_util::get_version_info!();
 293             println!("{}", version_info);
 294             exit(0);
 295         }
 296
 297         // Setting RUSTC_WRAPPER causes Cargo to pass 'rustc' as the first argument.
 298         // We're invoking the compiler programmatically, so we ignore this/
 299         let wrapper_mode = orig_args.get(1).map(Path::new).and_then(Path::file_stem) == Some("rustc".as_ref());
 300
 301         if wrapper_mode {
 302             // we still want to be able to invoke it normally though
 303             orig_args.remove(1);
 304         }
 305
 306         if !wrapper_mode && (orig_args.iter().any(|a| a == "--help" || a == "-h") || orig_args.len() == 1) {
 307             display_help();
 308             exit(0);
 309         }
 310
 311         // this conditional check for the --sysroot flag is there so users can call
 312         // `clippy_driver` directly
 313         // without having to pass --sysroot or anything
 314         let mut args: Vec<String> = orig_args.clone();
 315         if !have_sys_root_arg {
 316             args.extend(vec!["--sysroot".into(), sys_root]);
 317         };
 318
 319         let mut no_deps = false;
 320         let clippy_args_var = env::var("CLIPPY_ARGS").ok();
 321         let clippy_args = clippy_args_var
 322             .as_deref()
 323             .unwrap_or_default()
 324             .split("__CLIPPY_HACKERY__")
 325             .filter_map(|s| match s {
 326                 "" => None,
 327                 "--no-deps" => {
 328                     no_deps = true;
 329                     None
 330                 },
 331                 _ => Some(s.to_string()),
 332             })
 333             .chain(vec!["--cfg".into(), r#"feature="cargo-clippy""#.into()])
 334             .collect::<Vec<String>>();
 335
 336         // We enable Clippy if one of the following conditions is met
 337         // - IF Clippy is run on its test suite OR
 338         // - IF Clippy is run on the main crate, not on deps (`!cap_lints_allow`) THEN
 339         //    - IF `--no-deps` is not set (`!no_deps`) OR
 340         //    - IF `--no-deps` is set and Clippy is run on the specified primary package
 341         let cap_lints_allow = arg_value(&orig_args, "--cap-lints", |val| val == "allow").is_some()
 342             && arg_value(&orig_args, "--force-warn", |val| val.contains("clippy::")).is_none();
 343         let in_primary_package = env::var("CARGO_PRIMARY_PACKAGE").is_ok();
 344
 345         let clippy_enabled = !cap_lints_allow && (!no_deps || in_primary_package);
 346         if clippy_enabled {
 347             args.extend(clippy_args);
 348             rustc_driver::RunCompiler::new(&args, &mut ClippyCallbacks { clippy_args_var }).run()
 349         } else {
 350             rustc_driver::RunCompiler::new(&args, &mut RustcCallbacks { clippy_args_var }).run()
 351         }
 352     }))
 353 }