Review

crates/uv-install-wheel/Cargo.toml

@@ -29,6 +29,7 @@ uv-normalize = { workspace = true }
 uv-pep440 = { workspace = true }
 uv-pypi-types = { workspace = true }
 uv-shell = { workspace = true }
+uv-trampoline-builder = { workspace = true }
 uv-warnings = { workspace = true }
 
 clap = { workspace = true, optional = true, features = ["derive"] }
@@ -51,8 +52,6 @@ tracing = { workspace = true }
 walkdir = { workspace = true }
 
 [target.'cfg(target_os = "windows")'.dependencies]
-uv-trampoline-builder = { workspace = true }
-
 same-file = { workspace = true }
 self-replace = { workspace = true }
 

crates/uv-install-wheel/src/lib.rs

@@ -80,7 +80,6 @@ pub enum Error {
     MismatchedVersion(Version, Version),
     #[error("Invalid egg-link")]
     InvalidEggLink(PathBuf),
-    #[cfg(windows)]
     #[error(transparent)]
     LauncherError(#[from] uv_trampoline_builder::Error),
     #[error("Scripts must not use the reserved name {0}")]

crates/uv-install-wheel/src/wheel.rs

@@ -17,6 +17,7 @@ use uv_fs::{Simplified, persist_with_retry_sync, relative_to};
 use uv_normalize::PackageName;
 use uv_pypi_types::DirectUrl;
 use uv_shell::escape_posix_for_single_quotes;
+use uv_trampoline_builder::windows_script_launcher;
 use uv_warnings::warn_user_once;
 
 use crate::record::RecordEntry;
@@ -225,18 +226,14 @@ pub(crate) fn write_script_entrypoints(
         );
 
         // If necessary, wrap the launcher script in a Windows launcher binary.
-        #[cfg(windows)]
+        if cfg!(windows) {
-        {
-            use uv_trampoline_builder::windows_script_launcher;
             write_file_recorded(
                 site_packages,
                 &entrypoint_relative,
                 &windows_script_launcher(&launcher_python_script, is_gui, &launcher_executable)?,
                 record,
             )?;
-        }
+        } else {
-        #[cfg(not(windows))]
-        {
             write_file_recorded(
                 site_packages,
                 &entrypoint_relative,

crates/uv-python/Cargo.toml

@@ -34,6 +34,7 @@ uv-pypi-types = { workspace = true }
 uv-redacted = { workspace = true }
 uv-state = { workspace = true }
 uv-static = { workspace = true }
+uv-trampoline-builder = { workspace = true }
 uv-warnings = { workspace = true }
 
 anyhow = { workspace = true }
@@ -68,8 +69,6 @@ which = { workspace = true }
 once_cell = { workspace = true }
 
 [target.'cfg(target_os = "windows")'.dependencies]
-uv-trampoline-builder = { workspace = true }
-
 windows-registry = { workspace = true }
 windows-result = { workspace = true }
 windows-sys = { workspace = true }

crates/uv-python/src/managed.rs

@@ -20,6 +20,7 @@ use uv_platform::{Error as PlatformError, Os};
 use uv_platform::{LibcDetectionError, Platform};
 use uv_state::{StateBucket, StateStore};
 use uv_static::EnvVars;
+use uv_trampoline_builder::{Launcher, LauncherKind};
 
 use crate::downloads::{Error as DownloadError, ManagedPythonDownload};
 use crate::implementation::{
@@ -92,7 +93,6 @@ pub enum Error {
     },
     #[error("Failed to find a directory to install executables into")]
     NoExecutableDirectory,
-    #[cfg(windows)]
     #[error(transparent)]
     LauncherError(#[from] uv_trampoline_builder::Error),
     #[error("Failed to read managed Python directory name: {0}")]
@@ -619,13 +619,9 @@ impl ManagedPythonInstallation {
     /// Returns `true` if the path is a link to this installation's binary, e.g., as created by
     /// [`create_bin_link`].
     pub fn is_bin_link(&self, path: &Path) -> bool {
-        #[cfg(unix)]
+        if cfg!(unix) {
-        {
             same_file::is_same_file(path, self.executable(false)).unwrap_or_default()
-        }
+        } else if cfg!(windows) {
-        #[cfg(windows)]
-        {
-            use uv_trampoline_builder::{Launcher, LauncherKind};
             let Some(launcher) = Launcher::try_from_path(path).unwrap_or_default() else {
                 return false;
             };
@@ -637,9 +633,7 @@ impl ManagedPythonInstallation {
             // directly.
             dunce::canonicalize(&launcher.python_path).unwrap_or(launcher.python_path)
                 == self.executable(false)
-        }
+        } else {
-        #[cfg(not(any(unix, windows)))]
-        {
             unreachable!("Only Windows and Unix are supported")
         }
     }
@@ -882,8 +876,7 @@ pub fn create_link_to_executable(link: &Path, executable: &Path) -> Result<(), E
         err,
     })?;
 
-    #[cfg(unix)]
+    if cfg!(unix) {
-    {
         // Note this will never copy on Unix — we use it here to allow compilation on Windows
         match symlink_or_copy_file(executable, link) {
             Ok(()) => Ok(()),
@@ -896,9 +889,7 @@ pub fn create_link_to_executable(link: &Path, executable: &Path) -> Result<(), E
                 err,
             }),
         }
-    }
+    } else if cfg!(windows) {
-    #[cfg(windows)]
-    {
         use uv_trampoline_builder::windows_python_launcher;
 
         // TODO(zanieb): Install GUI launchers as well
@@ -916,10 +907,8 @@ pub fn create_link_to_executable(link: &Path, executable: &Path) -> Result<(), E
                     err,
                 })
         }
-    }
+    } else {
-    #[cfg(not(any(unix, windows)))]
+        unimplemented!("Only Windows and Unix are supported.")
-    {
-        unimplemented!("Only Windows and Unix systems are supported.")
     }
 }
 

crates/uv-trampoline-builder/src/lib.rs

@@ -51,18 +51,21 @@ pub struct Launcher {
 }
 
 impl Launcher {
+    /// Attempt to read [`Launcher`] metadata from a trampoline executable file.
+    ///
+    /// On Unix, this always returns [`None`]. Trampolines are a Windows-specific feature and cannot
+    /// be read on other platforms.
+    #[cfg(not(windows))]
+    pub fn try_from_path(_path: &Path) -> Result<Option<Self>, Error> {
+        Ok(None)
+    }
+
     /// Read [`Launcher`] metadata from a trampoline executable file.
     ///
     /// Returns `Ok(None)` if the file is not a trampoline executable.
     /// Returns `Err` if the file looks like a trampoline executable but is formatted incorrectly.
-    #[allow(unused_variables)]
-    pub fn try_from_path(path: &Path) -> Result<Option<Self>, Error> {
-        #[cfg(not(windows))]
-        {
-            Err(Error::NotWindows)
-        }
     #[cfg(windows)]
-        {
+    pub fn try_from_path(path: &Path) -> Result<Option<Self>, Error> {
         use std::os::windows::ffi::OsStrExt;
         use windows::Win32::System::LibraryLoader::LOAD_LIBRARY_AS_DATAFILE;
         use windows::Win32::System::LibraryLoader::LoadLibraryExW;
@@ -98,8 +101,7 @@ impl Launcher {
                 return Ok(None);
             };
             let python_path = PathBuf::from(
-                    String::from_utf8(path_data)
+                String::from_utf8(path_data).map_err(|err| Error::InvalidPath(err.utf8_error()))?,
-                        .map_err(|err| Error::InvalidPath(err.utf8_error()))?,
             );
 
             let script_data = read_resource(module, RESOURCE_SCRIPT_DATA);
@@ -120,16 +122,19 @@ impl Launcher {
 
         result
     }
-    }
 
-    #[allow(unused_variables)]
+    /// Write this trampoline launcher to a file.
-    pub fn write_to_file(self, file_path: &Path, is_gui: bool) -> Result<(), Error> {
+    ///
+    /// On Unix, this always returns [`Error::NotWindows`]. Trampolines are a Windows-specific
+    /// feature and cannot be written on other platforms.
     #[cfg(not(windows))]
-        {
+    pub fn write_to_file(self, _file_path: &Path, _is_gui: bool) -> Result<(), Error> {
         Err(Error::NotWindows)
     }
+
+    /// Write this trampoline launcher to a file.
     #[cfg(windows)]
-        {
+    pub fn write_to_file(self, file_path: &Path, is_gui: bool) -> Result<(), Error> {
         use uv_fs::Simplified;
         let python_path = self.python_path.simplified_display().to_string();
 
@@ -154,7 +159,6 @@ impl Launcher {
 
         Ok(())
     }
-    }
 
     #[must_use]
     pub fn with_python_path(self, path: PathBuf) -> Self {
@@ -251,7 +255,6 @@ fn get_launcher_bin(gui: bool) -> Result<&'static [u8], Error> {
 }
 
 /// Helper to write Windows PE resources
-#[allow(unused_variables)]
 #[cfg(windows)]
 fn write_resources(path: &Path, resources: &[(windows::core::PCWSTR, &[u8])]) -> Result<(), Error> {
     // SAFETY: winapi calls; null-terminated strings
@@ -289,8 +292,8 @@ fn write_resources(path: &Path, resources: &[(windows::core::PCWSTR, &[u8])]) ->
     Ok(())
 }
 
-#[cfg(windows)]
 /// Safely reads a resource from a PE file
+#[cfg(windows)]
 fn read_resource(
     handle: windows::Win32::Foundation::HMODULE,
     name: windows::core::PCWSTR,
@@ -327,24 +330,31 @@ fn read_resource(
     }
 }
 
+/// Construct a Windows script launcher.
+///
+/// On Unix, this always returns [`Error::NotWindows`]. Trampolines are a Windows-specific feature
+/// and cannot be created on other platforms.
+#[cfg(not(windows))]
+pub fn windows_script_launcher(
+    _launcher_python_script: &str,
+    _is_gui: bool,
+    _python_executable: impl AsRef<Path>,
+) -> Result<Vec<u8>, Error> {
+    Err(Error::NotWindows)
+}
+
+/// Construct a Windows script launcher.
+///
 /// A Windows script is a minimal .exe launcher binary with the python entrypoint script appended as
 /// stored zip file.
 ///
 /// <https://github.com/pypa/pip/blob/fd0ea6bc5e8cb95e518c23d901c26ca14db17f89/src/pip/_vendor/distlib/scripts.py#L248-L262>
-#[allow(unused_variables)]
+#[cfg(windows)]
 pub fn windows_script_launcher(
     launcher_python_script: &str,
     is_gui: bool,
     python_executable: impl AsRef<Path>,
 ) -> Result<Vec<u8>, Error> {
-    // This method should only be called on Windows, but we avoid function-scope
-    // `#[cfg(windows)]` to retain compilation on all platforms.
-    #[cfg(not(windows))]
-    {
-        Err(Error::NotWindows)
-    }
-    #[cfg(windows)]
-    {
     use std::io::{Cursor, Write};
 
     use zip::ZipWriter;
@@ -397,25 +407,30 @@ pub fn windows_script_launcher(
     fs_err::remove_file(temp_file)?;
 
     Ok(launcher)
-    }
 }
 
+/// Construct a Windows Python launcher.
+///
+/// On Unix, this always returns [`Error::NotWindows`]. Trampolines are a Windows-specific feature
+/// and cannot be created on other platforms.
+#[cfg(not(windows))]
+pub fn windows_python_launcher(
+    _python_executable: impl AsRef<Path>,
+    _is_gui: bool,
+) -> Result<Vec<u8>, Error> {
+    Err(Error::NotWindows)
+}
+
+/// Construct a Windows Python launcher.
+///
 /// A minimal .exe launcher binary for Python.
 ///
 /// Sort of equivalent to a `python` symlink on Unix.
-#[allow(unused_variables)]
+#[cfg(windows)]
 pub fn windows_python_launcher(
     python_executable: impl AsRef<Path>,
     is_gui: bool,
 ) -> Result<Vec<u8>, Error> {
-    // This method should only be called on Windows, but we avoid function-scope
-    // `#[cfg(windows)]` to retain compilation on all platforms.
-    #[cfg(not(windows))]
-    {
-        Err(Error::NotWindows)
-    }
-    #[cfg(windows)]
-    {
     use uv_fs::Simplified;
 
     let launcher_bin: &[u8] = get_launcher_bin(is_gui)?;
@@ -445,7 +460,6 @@ pub fn windows_python_launcher(
     fs_err::remove_file(temp_file)?;
 
     Ok(launcher)
-    }
 }
 
 #[cfg(all(test, windows))]

crates/uv/Cargo.toml

@@ -53,6 +53,7 @@ uv-shell = { workspace = true }
 uv-static = { workspace = true }
 uv-tool = { workspace = true }
 uv-torch = { workspace = true }
+uv-trampoline-builder = { workspace = true }
 uv-types = { workspace = true }
 uv-version = { workspace = true }
 uv-virtualenv = { workspace = true }
@@ -107,13 +108,8 @@ walkdir = { workspace = true }
 which = { workspace = true }
 zip = { workspace = true }
 
-[target.'cfg(target_os = "windows")'.dependencies]
-uv-trampoline-builder = { workspace = true }
-
 arrayvec = { workspace = true }
 self-replace = { workspace = true }
-windows = { workspace = true }
-windows-result = { workspace = true }
 
 [dev-dependencies]
 assert_cmd = { workspace = true }
@@ -135,6 +131,10 @@ whoami = { workspace = true }
 wiremock = { workspace = true }
 zip = { workspace = true }
 
+[target.'cfg(target_os = "windows")'.dependencies]
+windows = { workspace = true }
+windows-result = { workspace = true }
+
 [target.'cfg(unix)'.dependencies]
 nix = { workspace = true }
 

crates/uv/src/commands/python/install.rs

@@ -29,6 +29,7 @@ use uv_python::{
     PythonVersionFile, VersionFileDiscoveryOptions, VersionFilePreference, VersionRequest,
 };
 use uv_shell::Shell;
+use uv_trampoline_builder::{Launcher, LauncherKind};
 use uv_warnings::{warn_user, write_error_chain};
 
 use crate::commands::python::{ChangeEvent, ChangeEventKind};
@@ -1050,32 +1051,22 @@ fn find_matching_bin_link<'a>(
     mut installations: impl Iterator<Item = &'a ManagedPythonInstallation>,
     path: &Path,
 ) -> Option<&'a ManagedPythonInstallation> {
-    #[cfg(not(any(unix, windows)))]
+    if cfg!(unix) {
-    {
-        unreachable!("Only Windows and Unix are supported");
-    }
-
-    #[cfg(unix)]
-    {
         if !path.is_symlink() {
             return None;
         }
         let target = fs_err::canonicalize(path).ok()?;
 
         installations.find(|installation| installation.executable(false) == target)
-    }
+    } else if cfg!(windows) {
-    #[cfg(windows)]
+        let launcher = Launcher::try_from_path(path).ok()??;
-    {
-        let target = {
-            use uv_trampoline_builder::{Launcher, LauncherKind};
-
-            let launcher: Launcher = Launcher::try_from_path(path).ok()??;
         if !matches!(launcher.kind, LauncherKind::Python) {
             return None;
         }
-            dunce::canonicalize(launcher.python_path).ok()?
+        let target = dunce::canonicalize(launcher.python_path).ok()?;
-        };
 
         installations.find(|installation| installation.executable(false) == target)
+    } else {
+        unreachable!("Only Unix and Windows are supported")
     }
 }