Add uv pip check (astral-sh#2397)

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## Summary
Resolves astral-sh#2391
<!-- What's the purpose of the change? What does it do, and why? -->

## Test Plan
Added a few tests to make sure that the exit code returned is 0 when
there's no conflict; 1 when there's any conflict.
<!-- How was it tested? -->

crates/uv/src/commands/mod.rs

@@ -7,6 +7,7 @@ use owo_colors::OwoColorize;
 pub(crate) use cache_clean::cache_clean;
 pub(crate) use cache_dir::cache_dir;
 use distribution_types::InstalledMetadata;
+pub(crate) use pip_check::pip_check;
 pub(crate) use pip_compile::{extra_name_with_clap_error, pip_compile, Upgrade};
 pub(crate) use pip_freeze::pip_freeze;
 pub(crate) use pip_install::pip_install;
@@ -26,6 +27,7 @@ use crate::printer::Printer;
 
 mod cache_clean;
 mod cache_dir;
+mod pip_check;
 mod pip_compile;
 mod pip_freeze;
 mod pip_install;

crates/uv/src/commands/pip_check.rs

@@ -0,0 +1,59 @@
+use std::fmt::Write;
+
+use anyhow::Result;
+use owo_colors::OwoColorize;
+use tracing::debug;
+
+use uv_cache::Cache;
+use uv_fs::Simplified;
+use uv_installer::SitePackages;
+use uv_interpreter::PythonEnvironment;
+
+use crate::commands::ExitStatus;
+use crate::printer::Printer;
+
+/// Show information about one or more installed packages.
+pub(crate) fn pip_check(
+    python: Option<&str>,
+    system: bool,
+    cache: &Cache,
+    printer: Printer,
+) -> Result<ExitStatus> {
+    // Detect the current Python interpreter.
+    let venv = if let Some(python) = python {
+        PythonEnvironment::from_requested_python(python, cache)?
+    } else if system {
+        PythonEnvironment::from_default_python(cache)?
+    } else {
+        match PythonEnvironment::from_virtualenv(cache) {
+            Ok(venv) => venv,
+            Err(uv_interpreter::Error::VenvNotFound) => {
+                PythonEnvironment::from_default_python(cache)?
+            }
+            Err(err) => return Err(err.into()),
+        }
+    };
+
+    debug!(
+        "Using Python {} environment at {}",
+        venv.interpreter().python_version(),
+        venv.python_executable().simplified_display().cyan()
+    );
+
+    // Build the installed index.
+    let site_packages = SitePackages::from_executable(&venv)?;
+
+    let mut is_compatible = true;
+    // This loop is entered if and only if there is at least one conflict.
+    for diagnostic in site_packages.diagnostics()? {
+        is_compatible = false;
+        writeln!(printer.stdout(), "{}", diagnostic.message())?;
+    }
+
+    if !is_compatible {
+        return Ok(ExitStatus::Failure);
+    }
+
+    writeln!(printer.stdout(), "Installed packages pass the check.").unwrap();
+    Ok(ExitStatus::Success)
+}

crates/uv/src/main.rs

@@ -200,6 +200,8 @@ enum PipCommand {
     List(PipListArgs),
     /// Show information about one or more installed packages.
     Show(PipShowArgs),
+    /// Verify installed packages have compatible dependencies.
+    Check(PipCheckArgs),
 }
 
 /// Clap parser for the union of date and datetime
@@ -1095,6 +1097,47 @@ struct PipListArgs {
     system: bool,
 }
 
+#[derive(Args)]
+#[allow(clippy::struct_excessive_bools)]
+struct PipCheckArgs {
+    /// The Python interpreter for which packages should be listed.
+    ///
+    /// By default, `uv` lists packages in the currently activated virtual environment, or a virtual
+    /// environment (`.venv`) located in the current working directory or any parent directory,
+    /// falling back to the system Python if no virtual environment is found.
+    ///
+    /// Supported formats:
+    /// - `3.10` looks for an installed Python 3.10 using `py --list-paths` on Windows, or
+    ///   `python3.10` on Linux and macOS.
+    /// - `python3.10` or `python.exe` looks for a binary with the given name in `PATH`.
+    /// - `/home/ferris/.local/bin/python3.10` uses the exact Python at the given path.
+    #[clap(
+        long,
+        short,
+        verbatim_doc_comment,
+        conflicts_with = "system",
+        group = "discovery"
+    )]
+    python: Option<String>,
+
+    /// List packages for the system Python.
+    ///
+    /// By default, `uv` lists packages in the currently activated virtual environment, or a virtual
+    /// environment (`.venv`) located in the current working directory or any parent directory,
+    /// falling back to the system Python if no virtual environment is found. The `--system` option
+    /// instructs `uv` to use the first Python found in the system `PATH`.
+    ///
+    /// WARNING: `--system` is intended for use in continuous integration (CI) environments and
+    /// should be used with caution.
+    #[clap(
+        long,
+        conflicts_with = "python",
+        env = "UV_SYSTEM_PYTHON",
+        group = "discovery"
+    )]
+    system: bool,
+}
+
 #[derive(Args)]
 #[allow(clippy::struct_excessive_bools)]
 struct PipShowArgs {
@@ -1689,6 +1732,9 @@ async fn run() -> Result<ExitStatus> {
             &cache,
             printer,
         ),
+        Commands::Pip(PipNamespace {
+            command: PipCommand::Check(args),
+        }) => commands::pip_check(args.python.as_deref(), args.system, &cache, printer),
         Commands::Cache(CacheNamespace {
             command: CacheCommand::Clean(args),
         })

crates/uv/tests/pip_check.rs

@@ -0,0 +1,230 @@
+use std::process::Command;
+
+use anyhow::Result;
+use assert_fs::fixture::PathChild;
+use assert_fs::fixture::{FileTouch, FileWriteStr};
+
+use common::uv_snapshot;
+
+use crate::common::{get_bin, TestContext, EXCLUDE_NEWER};
+
+mod common;
+
+/// Create a `pip install` command with options shared across scenarios.
+fn install_command(context: &TestContext) -> Command {
+    let mut command = Command::new(get_bin());
+    command
+        .arg("pip")
+        .arg("install")
+        .arg("--cache-dir")
+        .arg(context.cache_dir.path())
+        .arg("--exclude-newer")
+        .arg(EXCLUDE_NEWER)
+        .env("VIRTUAL_ENV", context.venv.as_os_str())
+        .current_dir(&context.temp_dir);
+
+    if cfg!(all(windows, debug_assertions)) {
+        // TODO(konstin): Reduce stack usage in debug mode enough that the tests pass with the
+        // default windows stack of 1MB
+        command.env("UV_STACK_SIZE", (2 * 1024 * 1024).to_string());
+    }
+
+    command
+}
+
+#[test]
+fn check_compatible_packages() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.touch()?;
+    requirements_txt.write_str("requests==2.31.0")?;
+
+    uv_snapshot!(install_command(&context)
+        .arg("-r")
+        .arg("requirements.txt")
+        .arg("--strict"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 5 packages in [TIME]
+    Downloaded 5 packages in [TIME]
+    Installed 5 packages in [TIME]
+     + certifi==2023.11.17
+     + charset-normalizer==3.3.2
+     + idna==3.4
+     + requests==2.31.0
+     + urllib3==2.1.0
+    "###
+    );
+
+    // Guards against the package names being sorted.
+    uv_snapshot!([], Command::new(get_bin())
+        .arg("pip")
+        .arg("check")
+        .arg("--cache-dir")
+        .arg(context.cache_dir.path())
+        .env("VIRTUAL_ENV", context.venv.as_os_str())
+        .current_dir(&context.temp_dir), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    Installed packages pass the check.
+
+    ----- stderr -----
+    "###
+    );
+
+    Ok(())
+}
+
+// requests 2.31.0 requires idna (<4,>=2.5)
+// this test force-installs idna 2.4 to trigger a failure.
+#[test]
+fn check_incompatible_packages() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.touch()?;
+    requirements_txt.write_str("requests==2.31.0")?;
+
+    uv_snapshot!(install_command(&context)
+        .arg("-r")
+        .arg("requirements.txt")
+        .arg("--strict"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 5 packages in [TIME]
+    Downloaded 5 packages in [TIME]
+    Installed 5 packages in [TIME]
+     + certifi==2023.11.17
+     + charset-normalizer==3.3.2
+     + idna==3.4
+     + requests==2.31.0
+     + urllib3==2.1.0
+    "###
+    );
+
+    let requirements_txt_idna = context.temp_dir.child("requirements_idna.txt");
+    requirements_txt_idna.touch()?;
+    requirements_txt_idna.write_str("idna==2.4")?;
+
+    uv_snapshot!(install_command(&context)
+        .arg("-r")
+        .arg("requirements_idna.txt")
+        .arg("--strict"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 1 package in [TIME]
+    Downloaded 1 package in [TIME]
+    Installed 1 package in [TIME]
+     - idna==3.4
+     + idna==2.4
+    warning: The package `requests` requires `idna <4, >=2.5`, but `2.4` is installed.
+    "###
+    );
+
+    // Guards against the package names being sorted.
+    uv_snapshot!([], Command::new(get_bin())
+        .arg("pip")
+        .arg("check")
+        .arg("--cache-dir")
+        .arg(context.cache_dir.path())
+        .env("VIRTUAL_ENV", context.venv.as_os_str())
+        .current_dir(&context.temp_dir), @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    The package `requests` requires `idna <4, >=2.5`, but `2.4` is installed.
+
+    ----- stderr -----
+    "###
+    );
+
+    Ok(())
+}
+
+// requests 2.31.0 requires idna (<4,>=2.5) and urllib3<3,>=1.21.1
+// this test force-installs idna 2.4 and urllib3 1.20 to trigger a failure
+// with multiple incompatible packages.
+#[test]
+fn check_multiple_incompatible_packages() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.touch()?;
+    requirements_txt.write_str("requests==2.31.0")?;
+
+    uv_snapshot!(install_command(&context)
+        .arg("-r")
+        .arg("requirements.txt")
+        .arg("--strict"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 5 packages in [TIME]
+    Downloaded 5 packages in [TIME]
+    Installed 5 packages in [TIME]
+     + certifi==2023.11.17
+     + charset-normalizer==3.3.2
+     + idna==3.4
+     + requests==2.31.0
+     + urllib3==2.1.0
+    "###
+    );
+
+    let requirements_txt_two = context.temp_dir.child("requirements_two.txt");
+    requirements_txt_two.touch()?;
+    requirements_txt_two.write_str("idna==2.4\nurllib3==1.20")?;
+
+    uv_snapshot!(install_command(&context)
+        .arg("-r")
+        .arg("requirements_two.txt")
+        .arg("--strict"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    Downloaded 2 packages in [TIME]
+    Installed 2 packages in [TIME]
+     - idna==3.4
+     + idna==2.4
+     - urllib3==2.1.0
+     + urllib3==1.20
+    warning: The package `requests` requires `idna <4, >=2.5`, but `2.4` is installed.
+    warning: The package `requests` requires `urllib3 <3, >=1.21.1`, but `1.20` is installed.
+    "###
+    );
+
+    // Guards against the package names being sorted.
+    uv_snapshot!([], Command::new(get_bin())
+        .arg("pip")
+        .arg("check")
+        .arg("--cache-dir")
+        .arg(context.cache_dir.path())
+        .env("VIRTUAL_ENV", context.venv.as_os_str())
+        .current_dir(&context.temp_dir), @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    The package `requests` requires `idna <4, >=2.5`, but `2.4` is installed.
+    The package `requests` requires `urllib3 <3, >=1.21.1`, but `1.20` is installed.
+
+    ----- stderr -----
+    "###
+    );
+
+    Ok(())
+}