[ty] Add a --quiet mode (astral-sh#19233)

Adds a `--quiet` flag which silences diagnostic, warning logs, and
messages like "all checks passed" while retaining summary messages that
indicate problems, e.g., the number of diagnostics.

I'm a bit on the fence regarding filtering out warning logs, because it
can omit important details, e.g., the message that a fatal diagnostic
was encountered. Let's discuss that in
astral-sh#19233 (comment)

The implementation recycles the `Printer` abstraction used in uv, which
is intended to replace all direct usage of `std::io::stdout`. See
astral-sh#19233 (comment)

I ended up futzing with the progress bar more than I probably should
have to ensure it was also using the printer, but it doesn't seem like a
big deal. See
astral-sh#19233 (comment)

Closes astral-sh/ty#772

Author: zanieb

crates/ty/docs/cli.md

@@ -1,19 +1,21 @@
 mod args;
 mod logging;
+mod printer;
 mod python_version;
 mod version;
 
 pub use args::Cli;
 use ty_static::EnvVars;
 
-use std::io::{self, BufWriter, Write, stdout};
+use std::fmt::Write;
 use std::process::{ExitCode, Termination};
 
 use anyhow::Result;
 use std::sync::Mutex;
 
 use crate::args::{CheckCommand, Command, TerminalColor};
 use crate::logging::setup_tracing;
+use crate::printer::Printer;
 use anyhow::{Context, anyhow};
 use clap::{CommandFactory, Parser};
 use colored::Colorize;
@@ -25,7 +27,7 @@ use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
 use salsa::plumbing::ZalsaDatabase;
 use ty_project::metadata::options::ProjectOptionsOverrides;
 use ty_project::watch::ProjectWatcher;
-use ty_project::{Db, DummyReporter, Reporter, watch};
+use ty_project::{Db, watch};
 use ty_project::{ProjectDatabase, ProjectMetadata};
 use ty_server::run_server;
 
@@ -42,14 +44,16 @@ pub fn run() -> anyhow::Result<ExitStatus> {
         Command::Check(check_args) => run_check(check_args),
         Command::Version => version().map(|()| ExitStatus::Success),
         Command::GenerateShellCompletion { shell } => {
+            use std::io::stdout;
+
             shell.generate(&mut Cli::command(), &mut stdout());
             Ok(ExitStatus::Success)
         }
     }
 }
 
 pub(crate) fn version() -> Result<()> {
-    let mut stdout = BufWriter::new(io::stdout().lock());
+    let mut stdout = Printer::default().stream_for_requested_summary().lock();
     let version_info = crate::version::version();
     writeln!(stdout, "ty {}", &version_info)?;
     Ok(())
@@ -61,6 +65,8 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
     let verbosity = args.verbosity.level();
     let _guard = setup_tracing(verbosity, args.color.unwrap_or_default())?;
 
+    let printer = Printer::default().with_verbosity(verbosity);
+
     tracing::warn!(
         "ty is pre-release software and not ready for production use. \
             Expect to encounter bugs, missing features, and fatal errors.",
@@ -125,7 +131,8 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
     }
 
     let project_options_overrides = ProjectOptionsOverrides::new(config_file, options);
-    let (main_loop, main_loop_cancellation_token) = MainLoop::new(project_options_overrides);
+    let (main_loop, main_loop_cancellation_token) =
+        MainLoop::new(project_options_overrides, printer);
 
     // Listen to Ctrl+C and abort the watch mode.
     let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
@@ -143,7 +150,7 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
         main_loop.run(&mut db)?
     };
 
-    let mut stdout = stdout().lock();
+    let mut stdout = printer.stream_for_requested_summary().lock();
     match std::env::var(EnvVars::TY_MEMORY_REPORT).as_deref() {
         Ok("short") => write!(stdout, "{}", db.salsa_memory_dump().display_short())?,
         Ok("mypy_primer") => write!(stdout, "{}", db.salsa_memory_dump().display_mypy_primer())?,
@@ -192,12 +199,16 @@ struct MainLoop {
     /// The file system watcher, if running in watch mode.
     watcher: Option<ProjectWatcher>,
 
+    /// Interface for displaying information to the user.
+    printer: Printer,
+
     project_options_overrides: ProjectOptionsOverrides,
 }
 
 impl MainLoop {
     fn new(
         project_options_overrides: ProjectOptionsOverrides,
+        printer: Printer,
     ) -> (Self, MainLoopCancellationToken) {
         let (sender, receiver) = crossbeam_channel::bounded(10);
 
@@ -207,6 +218,7 @@ impl MainLoop {
                 receiver,
                 watcher: None,
                 project_options_overrides,
+                printer,
             },
             MainLoopCancellationToken { sender },
         )
@@ -223,32 +235,24 @@ impl MainLoop {
 
         // Do not show progress bars with `--watch`, indicatif does not seem to
         // handle cancelling independent progress bars very well.
-        self.run_with_progress::<DummyReporter>(db)?;
+        // TODO(zanieb): We can probably use `MultiProgress` to handle this case in the future.
+        self.printer = self.printer.with_no_progress();
+        self.run(db)?;
 
         Ok(ExitStatus::Success)
     }
 
     fn run(self, db: &mut ProjectDatabase) -> Result<ExitStatus> {
-        self.run_with_progress::<IndicatifReporter>(db)
-    }
-
-    fn run_with_progress<R>(mut self, db: &mut ProjectDatabase) -> Result<ExitStatus>
-    where
-        R: Reporter + Default + 'static,
-    {
         self.sender.send(MainLoopMessage::CheckWorkspace).unwrap();
 
-        let result = self.main_loop::<R>(db);
+        let result = self.main_loop(db);
 
         tracing::debug!("Exiting main loop");
 
         result
     }
 
-    fn main_loop<R>(&mut self, db: &mut ProjectDatabase) -> Result<ExitStatus>
-    where
-        R: Reporter + Default + 'static,
-    {
+    fn main_loop(mut self, db: &mut ProjectDatabase) -> Result<ExitStatus> {
         // Schedule the first check.
         tracing::debug!("Starting main loop");
 
@@ -264,7 +268,7 @@ impl MainLoop {
                     // to prevent blocking the main loop here.
                     rayon::spawn(move || {
                         match salsa::Cancelled::catch(|| {
-                            let mut reporter = R::default();
+                            let mut reporter = IndicatifReporter::from(self.printer);
                             db.check_with_reporter(&mut reporter)
                         }) {
                             Ok(result) => {
@@ -299,10 +303,12 @@ impl MainLoop {
                             return Ok(ExitStatus::Success);
                         }
 
-                        let mut stdout = stdout().lock();
-
                         if result.is_empty() {
-                            writeln!(stdout, "{}", "All checks passed!".green().bold())?;
+                            writeln!(
+                                self.printer.stream_for_success_summary(),
+                                "{}",
+                                "All checks passed!".green().bold()
+                            )?;
 
                             if self.watcher.is_none() {
                                 return Ok(ExitStatus::Success);
@@ -311,14 +317,19 @@ impl MainLoop {
                             let mut max_severity = Severity::Info;
                             let diagnostics_count = result.len();
 
+                            let mut stdout = self.printer.stream_for_details().lock();
                             for diagnostic in result {
-                                write!(stdout, "{}", diagnostic.display(db, &display_config))?;
+                                // Only render diagnostics if they're going to be displayed, since doing
+                                // so is expensive.
+                                if stdout.is_enabled() {
+                                    write!(stdout, "{}", diagnostic.display(db, &display_config))?;
+                                }
 
                                 max_severity = max_severity.max(diagnostic.severity());
                             }
 
                             writeln!(
-                                stdout,
+                                self.printer.stream_for_failure_summary(),
                                 "Found {} diagnostic{}",
                                 diagnostics_count,
                                 if diagnostics_count > 1 { "s" } else { "" }
@@ -378,27 +389,53 @@ impl MainLoop {
 }
 
 /// A progress reporter for `ty check`.
-#[derive(Default)]
-struct IndicatifReporter(Option<indicatif::ProgressBar>);
+enum IndicatifReporter {
+    /// A constructed reporter that is not yet ready, contains the target for the progress bar.
+    Pending(indicatif::ProgressDrawTarget),
+    /// A reporter that is ready, containing a progress bar to report to.
+    ///
+    /// Initialization of the bar is deferred to [`ty_project::ProgressReporter::set_files`] so we
+    /// do not initialize the bar too early as it may take a while to collect the number of files to
+    /// process and we don't want to display an empty "0/0" bar.
+    Initialized(indicatif::ProgressBar),
+}
+
+impl From<Printer> for IndicatifReporter {
+    fn from(printer: Printer) -> Self {
+        Self::Pending(printer.progress_target())
+    }
+}
 
-impl ty_project::Reporter for IndicatifReporter {
+impl ty_project::ProgressReporter for IndicatifReporter {
     fn set_files(&mut self, files: usize) {
-        let progress = indicatif::ProgressBar::new(files as u64);
-        progress.set_style(
+        let target = match std::mem::replace(
+            self,
+            IndicatifReporter::Pending(indicatif::ProgressDrawTarget::hidden()),
+        ) {
+            Self::Pending(target) => target,
+            Self::Initialized(_) => panic!("The progress reporter should only be initialized once"),
+        };
+
+        let bar = indicatif::ProgressBar::with_draw_target(Some(files as u64), target);
+        bar.set_style(
             indicatif::ProgressStyle::with_template(
                 "{msg:8.dim} {bar:60.green/dim} {pos}/{len} files",
             )
             .unwrap()
             .progress_chars("--"),
         );
-        progress.set_message("Checking");
-
-        self.0 = Some(progress);
+        bar.set_message("Checking");
+        *self = Self::Initialized(bar);
     }
 
     fn report_file(&self, _file: &ruff_db::files::File) {
-        if let Some(ref progress_bar) = self.0 {
-            progress_bar.inc(1);
+        match self {
+            IndicatifReporter::Initialized(progress_bar) => {
+                progress_bar.inc(1);
+            }
+            IndicatifReporter::Pending(_) => {
+                panic!("`report_file` called before `set_files`")
+            }
         }
     }
 }

crates/ty/src/lib.rs

@@ -24,15 +24,32 @@ pub(crate) struct Verbosity {
         help = "Use verbose output (or `-vv` and `-vvv` for more verbose output)",
         action = clap::ArgAction::Count,
         global = true,
+        overrides_with = "quiet",
     )]
     verbose: u8,
+
+    #[arg(
+        long,
+        help = "Use quiet output",
+        action = clap::ArgAction::Count,
+        global = true,
+        overrides_with = "verbose",
+    )]
+    quiet: u8,
 }
 
 impl Verbosity {
-    /// Returns the verbosity level based on the number of `-v` flags.
+    /// Returns the verbosity level based on the number of `-v` and `-q` flags.
     ///
     /// Returns `None` if the user did not specify any verbosity flags.
     pub(crate) fn level(&self) -> VerbosityLevel {
+        // `--quiet` and `--verbose` are mutually exclusive in Clap, so we can just check one first.
+        match self.quiet {
+            0 => {}
+            _ => return VerbosityLevel::Quiet,
+            // TODO(zanieb): Add support for `-qq` with a "silent" mode
+        }
+
         match self.verbose {
             0 => VerbosityLevel::Default,
             1 => VerbosityLevel::Verbose,
@@ -42,9 +59,14 @@ impl Verbosity {
     }
 }
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Default)]
 pub(crate) enum VerbosityLevel {
+    /// Quiet output.  Only shows Ruff and ty events up to the [`ERROR`](tracing::Level::ERROR).
+    /// Silences output except for summary information.
+    Quiet,
+
     /// Default output level. Only shows Ruff and ty events up to the [`WARN`](tracing::Level::WARN).
+    #[default]
     Default,
 
     /// Enables verbose output. Emits Ruff and ty events up to the [`INFO`](tracing::Level::INFO).
@@ -62,6 +84,7 @@ pub(crate) enum VerbosityLevel {
 impl VerbosityLevel {
     const fn level_filter(self) -> LevelFilter {
         match self {
+            VerbosityLevel::Quiet => LevelFilter::ERROR,
             VerbosityLevel::Default => LevelFilter::WARN,
             VerbosityLevel::Verbose => LevelFilter::INFO,
             VerbosityLevel::ExtraVerbose => LevelFilter::DEBUG,