Rename Red Knot (#17820)

crates/ty/Cargo.toml

@@ -0,0 +1,49 @@
+[package]
+name = "ty"
+version = "0.0.0"
+edition.workspace = true
+rust-version.workspace = true
+homepage.workspace = true
+documentation.workspace = true
+repository.workspace = true
+authors.workspace = true
+license.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ruff_db = { workspace = true, features = ["os", "cache"] }
+ruff_python_ast = { workspace = true }
+ty_python_semantic = { workspace = true }
+ty_project = { workspace = true, features = ["zstd"] }
+ty_server = { workspace = true }
+
+anyhow = { workspace = true }
+argfile = { workspace = true }
+clap = { workspace = true, features = ["wrap_help"] }
+colored = { workspace = true }
+countme = { workspace = true, features = ["enable"] }
+crossbeam = { workspace = true }
+ctrlc = { version = "3.4.4" }
+jiff = { workspace = true }
+rayon = { workspace = true }
+salsa = { workspace = true }
+tracing = { workspace = true, features = ["release_max_level_debug"] }
+tracing-subscriber = { workspace = true, features = ["env-filter", "fmt"] }
+tracing-flame = { workspace = true }
+tracing-tree = { workspace = true }
+wild = { workspace = true }
+
+[dev-dependencies]
+ruff_db = { workspace = true, features = ["testing"] }
+ruff_python_trivia = { workspace = true }
+
+insta = { workspace = true, features = ["filters"] }
+insta-cmd = { workspace = true }
+filetime = { workspace = true }
+regex = { workspace = true }
+tempfile = { workspace = true }
+toml = { workspace = true }
+
+[lints]
+workspace = true

crates/ty/README.md

@@ -0,0 +1,25 @@
+# ty
+
+ty is an extremely fast type checker.
+Currently, it is a work-in-progress and not ready for user testing.
+
+ty is designed to prioritize good type inference, even in unannotated code,
+and aims to avoid false positives.
+
+While ty will produce similar results to mypy and pyright on many codebases,
+100% compatibility with these tools is a non-goal.
+On some codebases, ty's design decisions lead to different outcomes
+than you would get from running one of these more established tools.
+
+## Contributing
+
+Core type checking tests are written as Markdown code blocks.
+They can be found in [`ty_python_semantic/resources/mdtest`][resources-mdtest].
+See [`ty_test/README.md`][mdtest-readme] for more information
+on the test framework itself.
+
+The list of open issues can be found [here][open-issues].
+
+[mdtest-readme]: ../ty_test/README.md
+[open-issues]: https://github.com/astral-sh/ty/issues
+[resources-mdtest]: ../ty_python_semantic/resources/mdtest

crates/ty/build.rs

@@ -0,0 +1,104 @@
+use std::{
+    fs,
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+fn main() {
+    // The workspace root directory is not available without walking up the tree
+    // https://github.com/rust-lang/cargo/issues/3946
+    let workspace_root = Path::new(&std::env::var("CARGO_MANIFEST_DIR").unwrap())
+        .join("..")
+        .join("..");
+
+    commit_info(&workspace_root);
+
+    #[allow(clippy::disallowed_methods)]
+    let target = std::env::var("TARGET").unwrap();
+    println!("cargo::rustc-env=RUST_HOST_TARGET={target}");
+}
+
+fn commit_info(workspace_root: &Path) {
+    // If not in a git repository, do not attempt to retrieve commit information
+    let git_dir = workspace_root.join(".git");
+    if !git_dir.exists() {
+        return;
+    }
+
+    if let Some(git_head_path) = git_head(&git_dir) {
+        println!("cargo:rerun-if-changed={}", git_head_path.display());
+
+        let git_head_contents = fs::read_to_string(git_head_path);
+        if let Ok(git_head_contents) = git_head_contents {
+            // The contents are either a commit or a reference in the following formats
+            // - "<commit>" when the head is detached
+            // - "ref <ref>" when working on a branch
+            // If a commit, checking if the HEAD file has changed is sufficient
+            // If a ref, we need to add the head file for that ref to rebuild on commit
+            let mut git_ref_parts = git_head_contents.split_whitespace();
+            git_ref_parts.next();
+            if let Some(git_ref) = git_ref_parts.next() {
+                let git_ref_path = git_dir.join(git_ref);
+                println!("cargo:rerun-if-changed={}", git_ref_path.display());
+            }
+        }
+    }
+
+    let output = match Command::new("git")
+        .arg("log")
+        .arg("-1")
+        .arg("--date=short")
+        .arg("--abbrev=9")
+        .arg("--format=%H %h %cd %(describe)")
+        .output()
+    {
+        Ok(output) if output.status.success() => output,
+        _ => return,
+    };
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let mut parts = stdout.split_whitespace();
+    let mut next = || parts.next().unwrap();
+    let _commit_hash = next();
+    println!("cargo::rustc-env=TY_COMMIT_SHORT_HASH={}", next());
+    println!("cargo::rustc-env=TY_COMMIT_DATE={}", next());
+
+    // Describe can fail for some commits
+    // https://git-scm.com/docs/pretty-formats#Documentation/pretty-formats.txt-emdescribeoptionsem
+    if let Some(describe) = parts.next() {
+        let mut describe_parts = describe.split('-');
+        let _last_tag = describe_parts.next().unwrap();
+
+        // If this is the tagged commit, this component will be missing
+        println!(
+            "cargo::rustc-env=TY_LAST_TAG_DISTANCE={}",
+            describe_parts.next().unwrap_or("0")
+        );
+    }
+}
+
+fn git_head(git_dir: &Path) -> Option<PathBuf> {
+    // The typical case is a standard git repository.
+    let git_head_path = git_dir.join("HEAD");
+    if git_head_path.exists() {
+        return Some(git_head_path);
+    }
+    if !git_dir.is_file() {
+        return None;
+    }
+    // If `.git/HEAD` doesn't exist and `.git` is actually a file,
+    // then let's try to attempt to read it as a worktree. If it's
+    // a worktree, then its contents will look like this, e.g.:
+    //
+    //     gitdir: /home/andrew/astral/uv/main/.git/worktrees/pr2
+    //
+    // And the HEAD file we want to watch will be at:
+    //
+    //     /home/andrew/astral/uv/main/.git/worktrees/pr2/HEAD
+    let contents = fs::read_to_string(git_dir).ok()?;
+    let (label, worktree_path) = contents.split_once(':')?;
+    if label != "gitdir" {
+        return None;
+    }
+    let worktree_path = worktree_path.trim();
+    Some(PathBuf::from(worktree_path))
+}

crates/ty/docs/mypy_primer.md

@@ -0,0 +1,60 @@
+# Running `mypy_primer`
+
+## Basics
+
+`mypy_primer` can be run using `uvx --from "…" mypy_primer`. For example, to see the help message, run:
+
+```sh
+uvx --from "git+https://github.com/hauntsaninja/mypy_primer" mypy_primer -h
+```
+
+Alternatively, you can install the forked version of `mypy_primer` using:
+
+```sh
+uv tool install "git+https://github.com/hauntsaninja/mypy_primer"
+```
+
+and then run it using `uvx mypy_primer` or just `mypy_primer`, if your `PATH` is set up accordingly (see: [Tool executables]).
+
+## Showing the diagnostics diff between two Git revisions
+
+To show the diagnostics diff between two Git revisions (e.g. your feature branch and `main`), run:
+
+```sh
+mypy_primer \
+    --type-checker ty \
+    --old origin/main \
+    --new my/feature \
+    --debug \
+    --output concise \
+    --project-selector '/black$'
+```
+
+This will show the diagnostics diff for the `black` project between the `main` branch and your `my/feature` branch. To run the
+diff for all projects we currently enable in CI, use `--project-selector "/($(paste -s -d'|' crates/ty_python_semantic/resources/primer/good.txt))\$"`.
+
+You can also take a look at the [full list of ecosystem projects]. Note that some of them might still need a `ty_paths` configuration
+option to work correctly.
+
+## Avoiding recompilation
+
+If you want to run `mypy_primer` repeatedly, e.g. for different projects, but for the same combination of `--old` and `--new`, you
+can use set the `MYPY_PRIMER_NO_REBUILD` environment variable to avoid recompilation of ty:
+
+```sh
+MYPY_PRIMER_NO_REBUILD=1 mypy_primer …
+```
+
+## Running from a local copy of the repository
+
+If you are working on a local branch, you can use `mypy_primer`'s `--repo` option to specify the path to your local copy of the `ruff` repository.
+This allows `mypy_primer` to check out local branches:
+
+```sh
+mypy_primer --repo /path/to/ruff --old origin/main --new my/local-branch …
+```
+
+Note that you might need to clean up `/tmp/mypy_primer` in order for this to work correctly.
+
+[full list of ecosystem projects]: https://github.com/hauntsaninja/mypy_primer/blob/master/mypy_primer/projects.py
+[tool executables]: https://docs.astral.sh/uv/concepts/tools/#tool-executables

crates/ty/docs/tracing.md

@@ -0,0 +1,128 @@
+# Tracing
+
+Traces are a useful tool to narrow down the location of a bug or, at least, to understand why the compiler is doing a particular thing.
+Note, tracing messages with severity `debug` or greater are user-facing. They should be phrased accordingly.
+Tracing spans are only shown when using `-vvv`.
+
+## Verbosity levels
+
+The CLI supports different verbosity levels.
+
+- default: Only show errors and warnings.
+- `-v` activates `info!`: Show generally useful information such as paths of configuration files, detected platform, etc., but it's not a lot of messages, it's something you'll activate in CI by default. cargo build e.g. shows you which packages are fresh.
+- `-vv` activates `debug!` and timestamps: This should be enough information to get to the bottom of bug reports. When you're processing many packages or files, you'll get pages and pages of output, but each line is link to a specific action or state change.
+- `-vvv` activates `trace!` (only in debug builds) and shows tracing-spans: At this level, you're logging everything. Most of this is wasted, it's really slow, we dump e.g. the entire resolution graph. Only useful to developers, and you almost certainly want to use `TY_LOG` to filter it down to the area your investigating.
+
+## Better logging with `TY_LOG` and `RAYON_NUM_THREADS`
+
+By default, the CLI shows messages from the `ruff` and `ty` crates. Tracing messages from other crates are not shown.
+The `TY_LOG` environment variable allows you to customize which messages are shown by specifying one
+or more [filter directives](https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#directives).
+
+The `RAYON_NUM_THREADS` environment variable, meanwhile, can be used to control the level of concurrency ty uses.
+By default, ty will attempt to parallelize its work so that multiple files are checked simultaneously,
+but this can result in a confused logging output where messages from different threads are intertwined.
+To switch off concurrency entirely and have more readable logs, use `RAYON_NUM_THREADS=1`.
+
+### Examples
+
+#### Show all debug messages
+
+Shows debug messages from all crates.
+
+```bash
+TY_LOG=debug
+```
+
+#### Show salsa query execution messages
+
+Show the salsa `execute: my_query` messages in addition to all ty messages.
+
+```bash
+TY_LOG=ruff=trace,ty=trace,salsa=info
+```
+
+#### Show typing traces
+
+Only show traces for the `ty_python_semantic::types` module.
+
+```bash
+TY_LOG="ty_python_semantic::types"
+```
+
+Note: Ensure that you use `-vvv` to see tracing spans.
+
+#### Show messages for a single file
+
+Shows all messages that are inside of a span for a specific file.
+
+```bash
+TY_LOG=ty[{file=/home/micha/astral/test/x.py}]=trace
+```
+
+**Note**: Tracing still shows all spans because tracing can't know at the time of entering the span
+whether one if its children has the file `x.py`.
+
+**Note**: Salsa currently logs the entire memoized values. In our case, the source text and parsed AST.
+This very quickly leads to extremely long outputs.
+
+## Tracing and Salsa
+
+Be mindful about using `tracing` in Salsa queries, especially when using `warn` or `error` because it isn't guaranteed
+that the query will execute after restoring from a persistent cache. In which case the user won't see the message.
+
+For example, don't use `tracing` to show the user a message when generating a lint violation failed
+because the message would only be shown when linting the file the first time, but not on subsequent analysis
+runs or when restoring from a persistent cache. This can be confusing for users because they
+don't understand why a specific lint violation isn't raised. Instead, change your
+query to return the failure as part of the query's result or use a Salsa accumulator.
+
+## Tracing in tests
+
+You can use `ruff_db::testing::setup_logging` or `ruff_db::testing::setup_logging_with_filter` to set up logging in tests.
+
+```rust
+use ruff_db::testing::setup_logging;
+
+#[test]
+fn test() {
+  let _logging = setup_logging();
+
+  tracing::info!("This message will be printed to stderr");
+}
+```
+
+Note: Most test runners capture stderr and only show its output when a test fails.
+
+Note also that `setup_logging` only sets up logging for the current thread because [`set_global_default`](https://docs.rs/tracing/latest/tracing/subscriber/fn.set_global_default.html) can only be
+called **once**.
+
+## Release builds
+
+`trace!` events are removed in release builds.
+
+## Profiling
+
+ty generates a folded stack trace to the current directory named `tracing.folded` when setting the environment variable `TY_LOG_PROFILE` to `1` or `true`.
+
+```bash
+TY_LOG_PROFILE=1 ty -- --current-directory=../test -vvv
+```
+
+You can convert the textual representation into a visual one using `inferno`.
+
+```shell
+cargo install inferno
+```
+
+```shell
+# flamegraph
+cat tracing.folded | inferno-flamegraph > tracing-flamegraph.svg
+
+# flamechart
+cat tracing.folded | inferno-flamegraph --flamechart > tracing-flamechart.svg
+```
+
+![Example flamegraph](./tracing-flamegraph.png)
+
+See [`tracing-flame`](https://crates.io/crates/tracing-flame) for more details.

crates/ty/src/args.rs

@@ -0,0 +1,297 @@
+use crate::logging::Verbosity;
+use crate::python_version::PythonVersion;
+use clap::{ArgAction, ArgMatches, Error, Parser};
+use ruff_db::system::SystemPathBuf;
+use ty_project::metadata::options::{EnvironmentOptions, Options, TerminalOptions};
+use ty_project::metadata::value::{RangedValue, RelativePathBuf};
+use ty_python_semantic::lint;
+
+#[derive(Debug, Parser)]
+#[command(author, name = "ty", about = "An extremely fast Python type checker.")]
+#[command(version)]
+pub(crate) struct Args {
+    #[command(subcommand)]
+    pub(crate) command: Command,
+}
+
+#[derive(Debug, clap::Subcommand)]
+pub(crate) enum Command {
+    /// Check a project for type errors.
+    Check(CheckCommand),
+
+    /// Start the language server
+    Server,
+
+    /// Display ty's version
+    Version,
+}
+
+#[derive(Debug, Parser)]
+pub(crate) struct CheckCommand {
+    /// List of files or directories to check.
+    #[clap(
+        help = "List of files or directories to check [default: the project root]",
+        value_name = "PATH"
+    )]
+    pub paths: Vec<SystemPathBuf>,
+
+    /// Run the command within the given project directory.
+    ///
+    /// All `pyproject.toml` files will be discovered by walking up the directory tree from the given project directory,
+    /// as will the project's virtual environment (`.venv`) unless the `venv-path` option is set.
+    ///
+    /// Other command-line arguments (such as relative paths) will be resolved relative to the current working directory.
+    #[arg(long, value_name = "PROJECT")]
+    pub(crate) project: Option<SystemPathBuf>,
+
+    /// Path to the Python installation from which ty resolves type information and third-party dependencies.
+    ///
+    /// If not specified, ty will look at the `VIRTUAL_ENV` environment variable.
+    ///
+    /// ty will search in the path's `site-packages` directories for type information and
+    /// third-party imports.
+    ///
+    /// This option is commonly used to specify the path to a virtual environment.
+    #[arg(long, value_name = "PATH")]
+    pub(crate) python: Option<SystemPathBuf>,
+
+    /// Custom directory to use for stdlib typeshed stubs.
+    #[arg(long, value_name = "PATH", alias = "custom-typeshed-dir")]
+    pub(crate) typeshed: Option<SystemPathBuf>,
+
+    /// Additional path to use as a module-resolution source (can be passed multiple times).
+    #[arg(long, value_name = "PATH")]
+    pub(crate) extra_search_path: Option<Vec<SystemPathBuf>>,
+
+    /// Python version to assume when resolving types.
+    #[arg(long, value_name = "VERSION", alias = "target-version")]
+    pub(crate) python_version: Option<PythonVersion>,
+
+    /// Target platform to assume when resolving types.
+    ///
+    /// This is used to specialize the type of `sys.platform` and will affect the visibility
+    /// of platform-specific functions and attributes. If the value is set to `all`, no
+    /// assumptions are made about the target platform. If unspecified, the current system's
+    /// platform will be used.
+    #[arg(long, value_name = "PLATFORM", alias = "platform")]
+    pub(crate) python_platform: Option<String>,
+
+    #[clap(flatten)]
+    pub(crate) verbosity: Verbosity,
+
+    #[clap(flatten)]
+    pub(crate) rules: RulesArg,
+
+    /// The format to use for printing diagnostic messages.
+    #[arg(long)]
+    pub(crate) output_format: Option<OutputFormat>,
+
+    /// Control when colored output is used.
+    #[arg(long, value_name = "WHEN")]
+    pub(crate) color: Option<TerminalColor>,
+
+    /// Use exit code 1 if there are any warning-level diagnostics.
+    #[arg(long, conflicts_with = "exit_zero", default_missing_value = "true", num_args=0..1)]
+    pub(crate) error_on_warning: Option<bool>,
+
+    /// Always use exit code 0, even when there are error-level diagnostics.
+    #[arg(long)]
+    pub(crate) exit_zero: bool,
+
+    /// Watch files for changes and recheck files related to the changed files.
+    #[arg(long, short = 'W')]
+    pub(crate) watch: bool,
+
+    /// Respect file exclusions via `.gitignore` and other standard ignore files.
+    /// Use `--no-respect-gitignore` to disable.
+    #[arg(
+        long,
+        overrides_with("no_respect_ignore_files"),
+        help_heading = "File selection",
+        default_missing_value = "true",
+        num_args = 0..1
+    )]
+    respect_ignore_files: Option<bool>,
+    #[clap(long, overrides_with("respect_ignore_files"), hide = true)]
+    no_respect_ignore_files: bool,
+}
+
+impl CheckCommand {
+    pub(crate) fn into_options(self) -> Options {
+        let rules = if self.rules.is_empty() {
+            None
+        } else {
+            Some(
+                self.rules
+                    .into_iter()
+                    .map(|(rule, level)| (RangedValue::cli(rule), RangedValue::cli(level)))
+                    .collect(),
+            )
+        };
+
+        // --no-respect-gitignore defaults to false and is set true by CLI flag. If passed, override config file
+        // Otherwise, only pass this through if explicitly set (don't default to anything here to
+        // make sure that doesn't take precedence over an explicitly-set config file value)
+        let respect_ignore_files = self
+            .no_respect_ignore_files
+            .then_some(false)
+            .or(self.respect_ignore_files);
+        Options {
+            environment: Some(EnvironmentOptions {
+                python_version: self
+                    .python_version
+                    .map(|version| RangedValue::cli(version.into())),
+                python_platform: self
+                    .python_platform
+                    .map(|platform| RangedValue::cli(platform.into())),
+                python: self.python.map(RelativePathBuf::cli),
+                typeshed: self.typeshed.map(RelativePathBuf::cli),
+                extra_paths: self.extra_search_path.map(|extra_search_paths| {
+                    extra_search_paths
+                        .into_iter()
+                        .map(RelativePathBuf::cli)
+                        .collect()
+                }),
+            }),
+            terminal: Some(TerminalOptions {
+                output_format: self
+                    .output_format
+                    .map(|output_format| RangedValue::cli(output_format.into())),
+                error_on_warning: self.error_on_warning,
+            }),
+            rules,
+            respect_ignore_files,
+            ..Default::default()
+        }
+    }
+}
+
+/// A list of rules to enable or disable with a given severity.
+///
+/// This type is used to parse the `--error`, `--warn`, and `--ignore` arguments
+/// while preserving the order in which they were specified (arguments last override previous severities).
+#[derive(Debug)]
+pub(crate) struct RulesArg(Vec<(String, lint::Level)>);
+
+impl RulesArg {
+    fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
+    fn into_iter(self) -> impl Iterator<Item = (String, lint::Level)> {
+        self.0.into_iter()
+    }
+}
+
+impl clap::FromArgMatches for RulesArg {
+    fn from_arg_matches(matches: &ArgMatches) -> Result<Self, Error> {
+        let mut rules = Vec::new();
+
+        for (level, arg_id) in [
+            (lint::Level::Ignore, "ignore"),
+            (lint::Level::Warn, "warn"),
+            (lint::Level::Error, "error"),
+        ] {
+            let indices = matches.indices_of(arg_id).into_iter().flatten();
+            let levels = matches.get_many::<String>(arg_id).into_iter().flatten();
+            rules.extend(
+                indices
+                    .zip(levels)
+                    .map(|(index, rule)| (index, rule, level)),
+            );
+        }
+
+        // Sort by their index so that values specified later override earlier ones.
+        rules.sort_by_key(|(index, _, _)| *index);
+
+        Ok(Self(
+            rules
+                .into_iter()
+                .map(|(_, rule, level)| (rule.to_owned(), level))
+                .collect(),
+        ))
+    }
+
+    fn update_from_arg_matches(&mut self, matches: &ArgMatches) -> Result<(), Error> {
+        self.0 = Self::from_arg_matches(matches)?.0;
+        Ok(())
+    }
+}
+
+impl clap::Args for RulesArg {
+    fn augment_args(cmd: clap::Command) -> clap::Command {
+        const HELP_HEADING: &str = "Enabling / disabling rules";
+
+        cmd.arg(
+            clap::Arg::new("error")
+                .long("error")
+                .action(ArgAction::Append)
+                .help("Treat the given rule as having severity 'error'. Can be specified multiple times.")
+                .value_name("RULE")
+                .help_heading(HELP_HEADING),
+        )
+        .arg(
+            clap::Arg::new("warn")
+                .long("warn")
+                .action(ArgAction::Append)
+                .help("Treat the given rule as having severity 'warn'. Can be specified multiple times.")
+                .value_name("RULE")
+                .help_heading(HELP_HEADING),
+        )
+        .arg(
+            clap::Arg::new("ignore")
+                .long("ignore")
+                .action(ArgAction::Append)
+                .help("Disables the rule. Can be specified multiple times.")
+                .value_name("RULE")
+                .help_heading(HELP_HEADING),
+        )
+    }
+
+    fn augment_args_for_update(cmd: clap::Command) -> clap::Command {
+        Self::augment_args(cmd)
+    }
+}
+
+/// The diagnostic output format.
+#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
+pub enum OutputFormat {
+    /// Print diagnostics verbosely, with context and helpful hints.
+    ///
+    /// Diagnostic messages may include additional context and
+    /// annotations on the input to help understand the message.
+    #[default]
+    #[value(name = "full")]
+    Full,
+    /// Print diagnostics concisely, one per line.
+    ///
+    /// This will guarantee that each diagnostic is printed on
+    /// a single line. Only the most important or primary aspects
+    /// of the diagnostic are included. Contextual information is
+    /// dropped.
+    #[value(name = "concise")]
+    Concise,
+}
+
+impl From<OutputFormat> for ruff_db::diagnostic::DiagnosticFormat {
+    fn from(format: OutputFormat) -> ruff_db::diagnostic::DiagnosticFormat {
+        match format {
+            OutputFormat::Full => Self::Full,
+            OutputFormat::Concise => Self::Concise,
+        }
+    }
+}
+
+/// Control when colored output is used.
+#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
+pub(crate) enum TerminalColor {
+    /// Display colors if the output goes to an interactive terminal.
+    #[default]
+    Auto,
+
+    /// Always display colors.
+    Always,
+
+    /// Never display colors.
+    Never,
+}

crates/ty/src/logging.rs

@@ -0,0 +1,254 @@
+//! Sets up logging for ty
+
+use anyhow::Context;
+use colored::Colorize;
+use std::fmt;
+use std::fs::File;
+use std::io::BufWriter;
+use tracing::{Event, Subscriber};
+use tracing_subscriber::filter::LevelFilter;
+use tracing_subscriber::fmt::format::Writer;
+use tracing_subscriber::fmt::{FmtContext, FormatEvent, FormatFields};
+use tracing_subscriber::registry::LookupSpan;
+use tracing_subscriber::EnvFilter;
+
+/// Logging flags to `#[command(flatten)]` into your CLI
+#[derive(clap::Args, Debug, Clone, Default)]
+#[command(about = None, long_about = None)]
+pub(crate) struct Verbosity {
+    #[arg(
+        long,
+        short = 'v',
+        help = "Use verbose output (or `-vv` and `-vvv` for more verbose output)",
+        action = clap::ArgAction::Count,
+        global = true,
+    )]
+    verbose: u8,
+}
+
+impl Verbosity {
+    /// Returns the verbosity level based on the number of `-v` flags.
+    ///
+    /// Returns `None` if the user did not specify any verbosity flags.
+    pub(crate) fn level(&self) -> VerbosityLevel {
+        match self.verbose {
+            0 => VerbosityLevel::Default,
+            1 => VerbosityLevel::Verbose,
+            2 => VerbosityLevel::ExtraVerbose,
+            _ => VerbosityLevel::Trace,
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+pub(crate) enum VerbosityLevel {
+    /// Default output level. Only shows Ruff and ty events up to the [`WARN`](tracing::Level::WARN).
+    Default,
+
+    /// Enables verbose output. Emits Ruff and ty events up to the [`INFO`](tracing::Level::INFO).
+    /// Corresponds to `-v`.
+    Verbose,
+
+    /// Enables a more verbose tracing format and emits Ruff and ty events up to [`DEBUG`](tracing::Level::DEBUG).
+    /// Corresponds to `-vv`
+    ExtraVerbose,
+
+    /// Enables all tracing events and uses a tree-like output format. Corresponds to `-vvv`.
+    Trace,
+}
+
+impl VerbosityLevel {
+    const fn level_filter(self) -> LevelFilter {
+        match self {
+            VerbosityLevel::Default => LevelFilter::WARN,
+            VerbosityLevel::Verbose => LevelFilter::INFO,
+            VerbosityLevel::ExtraVerbose => LevelFilter::DEBUG,
+            VerbosityLevel::Trace => LevelFilter::TRACE,
+        }
+    }
+
+    pub(crate) const fn is_trace(self) -> bool {
+        matches!(self, VerbosityLevel::Trace)
+    }
+
+    pub(crate) const fn is_extra_verbose(self) -> bool {
+        matches!(self, VerbosityLevel::ExtraVerbose)
+    }
+}
+
+pub(crate) fn setup_tracing(level: VerbosityLevel) -> anyhow::Result<TracingGuard> {
+    use tracing_subscriber::prelude::*;
+
+    // The `TY_LOG` environment variable overrides the default log level.
+    let filter = if let Ok(log_env_variable) = std::env::var("TY_LOG") {
+        EnvFilter::builder()
+            .parse(log_env_variable)
+            .context("Failed to parse directives specified in TY_LOG environment variable.")?
+    } else {
+        match level {
+            VerbosityLevel::Default => {
+                // Show warning traces
+                EnvFilter::default().add_directive(LevelFilter::WARN.into())
+            }
+            level => {
+                let level_filter = level.level_filter();
+
+                // Show info|debug|trace events, but allow `TY_LOG` to override
+                let filter = EnvFilter::default().add_directive(
+                    format!("ty={level_filter}")
+                        .parse()
+                        .expect("Hardcoded directive to be valid"),
+                );
+
+                filter.add_directive(
+                    format!("ruff={level_filter}")
+                        .parse()
+                        .expect("Hardcoded directive to be valid"),
+                )
+            }
+        }
+    };
+
+    let (profiling_layer, guard) = setup_profile();
+
+    let registry = tracing_subscriber::registry()
+        .with(filter)
+        .with(profiling_layer);
+
+    if level.is_trace() {
+        let subscriber = registry.with(
+            tracing_tree::HierarchicalLayer::default()
+                .with_indent_lines(true)
+                .with_indent_amount(2)
+                .with_bracketed_fields(true)
+                .with_thread_ids(true)
+                .with_targets(true)
+                .with_writer(std::io::stderr)
+                .with_timer(tracing_tree::time::Uptime::default()),
+        );
+
+        subscriber.init();
+    } else {
+        let subscriber = registry.with(
+            tracing_subscriber::fmt::layer()
+                .event_format(TyFormat {
+                    display_level: true,
+                    display_timestamp: level.is_extra_verbose(),
+                    show_spans: false,
+                })
+                .with_writer(std::io::stderr),
+        );
+
+        subscriber.init();
+    }
+
+    Ok(TracingGuard {
+        _flame_guard: guard,
+    })
+}
+
+#[allow(clippy::type_complexity)]
+fn setup_profile<S>() -> (
+    Option<tracing_flame::FlameLayer<S, BufWriter<File>>>,
+    Option<tracing_flame::FlushGuard<BufWriter<File>>>,
+)
+where
+    S: Subscriber + for<'span> LookupSpan<'span>,
+{
+    if let Ok("1" | "true") = std::env::var("TY_LOG_PROFILE").as_deref() {
+        let (layer, guard) = tracing_flame::FlameLayer::with_file("tracing.folded")
+            .expect("Flame layer to be created");
+        (Some(layer), Some(guard))
+    } else {
+        (None, None)
+    }
+}
+
+pub(crate) struct TracingGuard {
+    _flame_guard: Option<tracing_flame::FlushGuard<BufWriter<File>>>,
+}
+
+struct TyFormat {
+    display_timestamp: bool,
+    display_level: bool,
+    show_spans: bool,
+}
+
+/// See <https://docs.rs/tracing-subscriber/0.3.18/src/tracing_subscriber/fmt/format/mod.rs.html#1026-1156>
+impl<S, N> FormatEvent<S, N> for TyFormat
+where
+    S: Subscriber + for<'a> LookupSpan<'a>,
+    N: for<'a> FormatFields<'a> + 'static,
+{
+    fn format_event(
+        &self,
+        ctx: &FmtContext<'_, S, N>,
+        mut writer: Writer<'_>,
+        event: &Event<'_>,
+    ) -> fmt::Result {
+        let meta = event.metadata();
+        let ansi = writer.has_ansi_escapes();
+
+        if self.display_timestamp {
+            let timestamp = jiff::Zoned::now()
+                .strftime("%Y-%m-%d %H:%M:%S.%f")
+                .to_string();
+            if ansi {
+                write!(writer, "{} ", timestamp.dimmed())?;
+            } else {
+                write!(
+                    writer,
+                    "{} ",
+                    jiff::Zoned::now().strftime("%Y-%m-%d %H:%M:%S.%f")
+                )?;
+            }
+        }
+
+        if self.display_level {
+            let level = meta.level();
+            // Same colors as tracing
+            if ansi {
+                let formatted_level = level.to_string();
+                match *level {
+                    tracing::Level::TRACE => {
+                        write!(writer, "{} ", formatted_level.purple().bold())?;
+                    }
+                    tracing::Level::DEBUG => write!(writer, "{} ", formatted_level.blue().bold())?,
+                    tracing::Level::INFO => write!(writer, "{} ", formatted_level.green().bold())?,
+                    tracing::Level::WARN => write!(writer, "{} ", formatted_level.yellow().bold())?,
+                    tracing::Level::ERROR => write!(writer, "{} ", level.to_string().red().bold())?,
+                }
+            } else {
+                write!(writer, "{level} ")?;
+            }
+        }
+
+        if self.show_spans {
+            let span = event.parent();
+            let mut seen = false;
+
+            let span = span
+                .and_then(|id| ctx.span(id))
+                .or_else(|| ctx.lookup_current());
+
+            let scope = span.into_iter().flat_map(|span| span.scope().from_root());
+
+            for span in scope {
+                seen = true;
+                if ansi {
+                    write!(writer, "{}:", span.metadata().name().bold())?;
+                } else {
+                    write!(writer, "{}:", span.metadata().name())?;
+                }
+            }
+
+            if seen {
+                writer.write_char(' ')?;
+            }
+        }
+
+        ctx.field_format().format_fields(writer.by_ref(), event)?;
+
+        writeln!(writer)
+    }
+}

crates/ty/src/main.rs

@@ -0,0 +1,395 @@
+use std::io::{self, stdout, BufWriter, Write};
+use std::process::{ExitCode, Termination};
+
+use anyhow::Result;
+use std::sync::Mutex;
+
+use crate::args::{Args, CheckCommand, Command, TerminalColor};
+use crate::logging::setup_tracing;
+use anyhow::{anyhow, Context};
+use clap::Parser;
+use colored::Colorize;
+use crossbeam::channel as crossbeam_channel;
+use ruff_db::diagnostic::{Diagnostic, DisplayDiagnosticConfig, Severity};
+use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
+use salsa::plumbing::ZalsaDatabase;
+use ty_project::metadata::options::Options;
+use ty_project::watch::ProjectWatcher;
+use ty_project::{watch, Db};
+use ty_project::{ProjectDatabase, ProjectMetadata};
+use ty_server::run_server;
+
+mod args;
+mod logging;
+mod python_version;
+mod version;
+
+#[allow(clippy::print_stdout, clippy::unnecessary_wraps, clippy::print_stderr)]
+pub fn main() -> ExitStatus {
+    run().unwrap_or_else(|error| {
+        use std::io::Write;
+
+        // Use `writeln` instead of `eprintln` to avoid panicking when the stderr pipe is broken.
+        let mut stderr = std::io::stderr().lock();
+
+        // This communicates that this isn't a linter error but ty itself hard-errored for
+        // some reason (e.g. failed to resolve the configuration)
+        writeln!(stderr, "{}", "ty failed".red().bold()).ok();
+        // Currently we generally only see one error, but e.g. with io errors when resolving
+        // the configuration it is help to chain errors ("resolving configuration failed" ->
+        // "failed to read file: subdir/pyproject.toml")
+        for cause in error.chain() {
+            // Exit "gracefully" on broken pipe errors.
+            //
+            // See: https://github.com/BurntSushi/ripgrep/blob/bf63fe8f258afc09bae6caa48f0ae35eaf115005/crates/core/main.rs#L47C1-L61C14
+            if let Some(ioerr) = cause.downcast_ref::<io::Error>() {
+                if ioerr.kind() == io::ErrorKind::BrokenPipe {
+                    return ExitStatus::Success;
+                }
+            }
+
+            writeln!(stderr, "  {} {cause}", "Cause:".bold()).ok();
+        }
+
+        ExitStatus::Error
+    })
+}
+
+fn run() -> anyhow::Result<ExitStatus> {
+    let args = wild::args_os();
+    let args = argfile::expand_args_from(args, argfile::parse_fromfile, argfile::PREFIX)
+        .context("Failed to read CLI arguments from file")?;
+    let args = Args::parse_from(args);
+
+    match args.command {
+        Command::Server => run_server().map(|()| ExitStatus::Success),
+        Command::Check(check_args) => run_check(check_args),
+        Command::Version => version().map(|()| ExitStatus::Success),
+    }
+}
+
+pub(crate) fn version() -> Result<()> {
+    let mut stdout = BufWriter::new(io::stdout().lock());
+    let version_info = crate::version::version();
+    writeln!(stdout, "ty {}", &version_info)?;
+    Ok(())
+}
+
+fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
+    set_colored_override(args.color);
+
+    let verbosity = args.verbosity.level();
+    countme::enable(verbosity.is_trace());
+    let _guard = setup_tracing(verbosity)?;
+
+    tracing::debug!("Version: {}", version::version());
+
+    // The base path to which all CLI arguments are relative to.
+    let cwd = {
+        let cwd = std::env::current_dir().context("Failed to get the current working directory")?;
+        SystemPathBuf::from_path_buf(cwd)
+            .map_err(|path| {
+                anyhow!(
+                    "The current working directory `{}` contains non-Unicode characters. ty only supports Unicode paths.",
+                    path.display()
+                )
+            })?
+    };
+
+    let project_path = args
+        .project
+        .as_ref()
+        .map(|project| {
+            if project.as_std_path().is_dir() {
+                Ok(SystemPath::absolute(project, &cwd))
+            } else {
+                Err(anyhow!(
+                    "Provided project path `{project}` is not a directory"
+                ))
+            }
+        })
+        .transpose()?
+        .unwrap_or_else(|| cwd.clone());
+
+    let check_paths: Vec<_> = args
+        .paths
+        .iter()
+        .map(|path| SystemPath::absolute(path, &cwd))
+        .collect();
+
+    let system = OsSystem::new(cwd);
+    let watch = args.watch;
+    let exit_zero = args.exit_zero;
+
+    let cli_options = args.into_options();
+    let mut project_metadata = ProjectMetadata::discover(&project_path, &system)?;
+    project_metadata.apply_cli_options(cli_options.clone());
+    project_metadata.apply_configuration_files(&system)?;
+
+    let mut db = ProjectDatabase::new(project_metadata, system)?;
+
+    if !check_paths.is_empty() {
+        db.project().set_included_paths(&mut db, check_paths);
+    }
+
+    let (main_loop, main_loop_cancellation_token) = MainLoop::new(cli_options);
+
+    // Listen to Ctrl+C and abort the watch mode.
+    let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
+    ctrlc::set_handler(move || {
+        let mut lock = main_loop_cancellation_token.lock().unwrap();
+
+        if let Some(token) = lock.take() {
+            token.stop();
+        }
+    })?;
+
+    let exit_status = if watch {
+        main_loop.watch(&mut db)?
+    } else {
+        main_loop.run(&mut db)?
+    };
+
+    tracing::trace!("Counts for entire CLI run:\n{}", countme::get_all());
+
+    std::mem::forget(db);
+
+    if exit_zero {
+        Ok(ExitStatus::Success)
+    } else {
+        Ok(exit_status)
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum ExitStatus {
+    /// Checking was successful and there were no errors.
+    Success = 0,
+
+    /// Checking was successful but there were errors.
+    Failure = 1,
+
+    /// Checking failed due to an invocation error (e.g. the current directory no longer exists, incorrect CLI arguments, ...)
+    Error = 2,
+
+    /// Internal ty error (panic, or any other error that isn't due to the user using the
+    /// program incorrectly or transient environment errors).
+    InternalError = 101,
+}
+
+impl Termination for ExitStatus {
+    fn report(self) -> ExitCode {
+        ExitCode::from(self as u8)
+    }
+}
+
+struct MainLoop {
+    /// Sender that can be used to send messages to the main loop.
+    sender: crossbeam_channel::Sender<MainLoopMessage>,
+
+    /// Receiver for the messages sent **to** the main loop.
+    receiver: crossbeam_channel::Receiver<MainLoopMessage>,
+
+    /// The file system watcher, if running in watch mode.
+    watcher: Option<ProjectWatcher>,
+
+    cli_options: Options,
+}
+
+impl MainLoop {
+    fn new(cli_options: Options) -> (Self, MainLoopCancellationToken) {
+        let (sender, receiver) = crossbeam_channel::bounded(10);
+
+        (
+            Self {
+                sender: sender.clone(),
+                receiver,
+                watcher: None,
+                cli_options,
+            },
+            MainLoopCancellationToken { sender },
+        )
+    }
+
+    fn watch(mut self, db: &mut ProjectDatabase) -> Result<ExitStatus> {
+        tracing::debug!("Starting watch mode");
+        let sender = self.sender.clone();
+        let watcher = watch::directory_watcher(move |event| {
+            sender.send(MainLoopMessage::ApplyChanges(event)).unwrap();
+        })?;
+
+        self.watcher = Some(ProjectWatcher::new(watcher, db));
+
+        self.run(db)?;
+
+        Ok(ExitStatus::Success)
+    }
+
+    fn run(mut self, db: &mut ProjectDatabase) -> Result<ExitStatus> {
+        self.sender.send(MainLoopMessage::CheckWorkspace).unwrap();
+
+        let result = self.main_loop(db);
+
+        tracing::debug!("Exiting main loop");
+
+        result
+    }
+
+    fn main_loop(&mut self, db: &mut ProjectDatabase) -> Result<ExitStatus> {
+        // Schedule the first check.
+        tracing::debug!("Starting main loop");
+
+        let mut revision = 0u64;
+
+        while let Ok(message) = self.receiver.recv() {
+            match message {
+                MainLoopMessage::CheckWorkspace => {
+                    let db = db.clone();
+                    let sender = self.sender.clone();
+
+                    // Spawn a new task that checks the project. This needs to be done in a separate thread
+                    // to prevent blocking the main loop here.
+                    rayon::spawn(move || {
+                        match db.check() {
+                            Ok(result) => {
+                                // Send the result back to the main loop for printing.
+                                sender
+                                    .send(MainLoopMessage::CheckCompleted { result, revision })
+                                    .unwrap();
+                            }
+                            Err(cancelled) => {
+                                tracing::debug!("Check has been cancelled: {cancelled:?}");
+                            }
+                        }
+                    });
+                }
+
+                MainLoopMessage::CheckCompleted {
+                    result,
+                    revision: check_revision,
+                } => {
+                    let terminal_settings = db.project().settings(db).terminal();
+                    let display_config = DisplayDiagnosticConfig::default()
+                        .format(terminal_settings.output_format)
+                        .color(colored::control::SHOULD_COLORIZE.should_colorize());
+
+                    if check_revision == revision {
+                        if db.project().files(db).is_empty() {
+                            tracing::warn!("No python files found under the given path(s)");
+                        }
+
+                        let mut stdout = stdout().lock();
+
+                        if result.is_empty() {
+                            writeln!(stdout, "All checks passed!")?;
+
+                            if self.watcher.is_none() {
+                                return Ok(ExitStatus::Success);
+                            }
+                        } else {
+                            let mut max_severity = Severity::Info;
+                            let diagnostics_count = result.len();
+
+                            for diagnostic in result {
+                                write!(stdout, "{}", diagnostic.display(db, &display_config))?;
+
+                                max_severity = max_severity.max(diagnostic.severity());
+                            }
+
+                            writeln!(
+                                stdout,
+                                "Found {} diagnostic{}",
+                                diagnostics_count,
+                                if diagnostics_count > 1 { "s" } else { "" }
+                            )?;
+
+                            if self.watcher.is_none() {
+                                return Ok(match max_severity {
+                                    Severity::Info => ExitStatus::Success,
+                                    Severity::Warning => {
+                                        if terminal_settings.error_on_warning {
+                                            ExitStatus::Failure
+                                        } else {
+                                            ExitStatus::Success
+                                        }
+                                    }
+                                    Severity::Error => ExitStatus::Failure,
+                                    Severity::Fatal => ExitStatus::InternalError,
+                                });
+                            }
+                        }
+                    } else {
+                        tracing::debug!(
+                            "Discarding check result for outdated revision: current: {revision}, result revision: {check_revision}"
+                        );
+                    }
+
+                    tracing::trace!("Counts after last check:\n{}", countme::get_all());
+                }
+
+                MainLoopMessage::ApplyChanges(changes) => {
+                    revision += 1;
+                    // Automatically cancels any pending queries and waits for them to complete.
+                    db.apply_changes(changes, Some(&self.cli_options));
+                    if let Some(watcher) = self.watcher.as_mut() {
+                        watcher.update(db);
+                    }
+                    self.sender.send(MainLoopMessage::CheckWorkspace).unwrap();
+                }
+                MainLoopMessage::Exit => {
+                    // Cancel any pending queries and wait for them to complete.
+                    // TODO: Don't use Salsa internal APIs
+                    //  [Zulip-Thread](https://salsa.zulipchat.com/#narrow/stream/333573-salsa-3.2E0/topic/Expose.20an.20API.20to.20cancel.20other.20queries)
+                    let _ = db.zalsa_mut();
+                    return Ok(ExitStatus::Success);
+                }
+            }
+
+            tracing::debug!("Waiting for next main loop message.");
+        }
+
+        Ok(ExitStatus::Success)
+    }
+}
+
+#[derive(Debug)]
+struct MainLoopCancellationToken {
+    sender: crossbeam_channel::Sender<MainLoopMessage>,
+}
+
+impl MainLoopCancellationToken {
+    fn stop(self) {
+        self.sender.send(MainLoopMessage::Exit).unwrap();
+    }
+}
+
+/// Message sent from the orchestrator to the main loop.
+#[derive(Debug)]
+enum MainLoopMessage {
+    CheckWorkspace,
+    CheckCompleted {
+        /// The diagnostics that were found during the check.
+        result: Vec<Diagnostic>,
+        revision: u64,
+    },
+    ApplyChanges(Vec<watch::ChangeEvent>),
+    Exit,
+}
+
+fn set_colored_override(color: Option<TerminalColor>) {
+    let Some(color) = color else {
+        return;
+    };
+
+    match color {
+        TerminalColor::Auto => {
+            colored::control::unset_override();
+        }
+        TerminalColor::Always => {
+            colored::control::set_override(true);
+        }
+        TerminalColor::Never => {
+            colored::control::set_override(false);
+        }
+    }
+}

crates/ty/src/python_version.rs

@@ -0,0 +1,68 @@
+/// Enumeration of all supported Python versions
+///
+/// TODO: unify with the `PythonVersion` enum in the linter/formatter crates?
+#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
+pub enum PythonVersion {
+    #[value(name = "3.7")]
+    Py37,
+    #[value(name = "3.8")]
+    Py38,
+    #[default]
+    #[value(name = "3.9")]
+    Py39,
+    #[value(name = "3.10")]
+    Py310,
+    #[value(name = "3.11")]
+    Py311,
+    #[value(name = "3.12")]
+    Py312,
+    #[value(name = "3.13")]
+    Py313,
+}
+
+impl PythonVersion {
+    const fn as_str(self) -> &'static str {
+        match self {
+            Self::Py37 => "3.7",
+            Self::Py38 => "3.8",
+            Self::Py39 => "3.9",
+            Self::Py310 => "3.10",
+            Self::Py311 => "3.11",
+            Self::Py312 => "3.12",
+            Self::Py313 => "3.13",
+        }
+    }
+}
+
+impl std::fmt::Display for PythonVersion {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl From<PythonVersion> for ruff_python_ast::PythonVersion {
+    fn from(value: PythonVersion) -> Self {
+        match value {
+            PythonVersion::Py37 => Self::PY37,
+            PythonVersion::Py38 => Self::PY38,
+            PythonVersion::Py39 => Self::PY39,
+            PythonVersion::Py310 => Self::PY310,
+            PythonVersion::Py311 => Self::PY311,
+            PythonVersion::Py312 => Self::PY312,
+            PythonVersion::Py313 => Self::PY313,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::python_version::PythonVersion;
+
+    #[test]
+    fn same_default_as_python_version() {
+        assert_eq!(
+            ruff_python_ast::PythonVersion::from(PythonVersion::default()),
+            ruff_python_ast::PythonVersion::default()
+        );
+    }
+}

crates/ty/src/version.rs

@@ -0,0 +1,104 @@
+//! Code for representing ty's release version number.
+use std::fmt;
+
+/// Information about the git repository where ty was built from.
+pub(crate) struct CommitInfo {
+    short_commit_hash: String,
+    commit_date: String,
+    commits_since_last_tag: u32,
+}
+
+/// ty's version.
+pub(crate) struct VersionInfo {
+    /// ty's version, such as "0.5.1"
+    version: String,
+    /// Information about the git commit we may have been built from.
+    ///
+    /// `None` if not built from a git repo or if retrieval failed.
+    commit_info: Option<CommitInfo>,
+}
+
+impl fmt::Display for VersionInfo {
+    /// Formatted version information: `<version>[+<commits>] (<commit> <date>)`
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.version)?;
+
+        if let Some(ref ci) = self.commit_info {
+            if ci.commits_since_last_tag > 0 {
+                write!(f, "+{}", ci.commits_since_last_tag)?;
+            }
+            write!(f, " ({} {})", ci.short_commit_hash, ci.commit_date)?;
+        }
+
+        Ok(())
+    }
+}
+
+/// Returns information about ty's version.
+pub(crate) fn version() -> VersionInfo {
+    // Environment variables are only read at compile-time
+    macro_rules! option_env_str {
+        ($name:expr) => {
+            option_env!($name).map(|s| s.to_string())
+        };
+    }
+
+    // This version is pulled from Cargo.toml and set by Cargo
+    let version = option_env_str!("CARGO_PKG_VERSION").unwrap();
+
+    // Commit info is pulled from git and set by `build.rs`
+    let commit_info = option_env_str!("TY_COMMIT_SHORT_HASH").map(|short_commit_hash| CommitInfo {
+        short_commit_hash,
+        commit_date: option_env_str!("TY_COMMIT_DATE").unwrap(),
+        commits_since_last_tag: option_env_str!("TY_LAST_TAG_DISTANCE")
+            .as_deref()
+            .map_or(0, |value| value.parse::<u32>().unwrap_or(0)),
+    });
+
+    VersionInfo {
+        version,
+        commit_info,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use insta::assert_snapshot;
+
+    use super::{CommitInfo, VersionInfo};
+
+    #[test]
+    fn version_formatting() {
+        let version = VersionInfo {
+            version: "0.0.0".to_string(),
+            commit_info: None,
+        };
+        assert_snapshot!(version, @"0.0.0");
+    }
+
+    #[test]
+    fn version_formatting_with_commit_info() {
+        let version = VersionInfo {
+            version: "0.0.0".to_string(),
+            commit_info: Some(CommitInfo {
+                short_commit_hash: "53b0f5d92".to_string(),
+                commit_date: "2023-10-19".to_string(),
+                commits_since_last_tag: 0,
+            }),
+        };
+        assert_snapshot!(version, @"0.0.0 (53b0f5d92 2023-10-19)");
+    }
+
+    #[test]
+    fn version_formatting_with_commits_since_last_tag() {
+        let version = VersionInfo {
+            version: "0.0.0".to_string(),
+            commit_info: Some(CommitInfo {
+                short_commit_hash: "53b0f5d92".to_string(),
+                commit_date: "2023-10-19".to_string(),
+                commits_since_last_tag: 24,
+            }),
+        };
+        assert_snapshot!(version, @"0.0.0+24 (53b0f5d92 2023-10-19)");
+    }
+}