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crates/uv-interpreter/src/get_interpreter_info.py

@@ -88,6 +88,7 @@ def format_full_version(info):
     "base_prefix": sys.base_prefix,
     "base_exec_prefix": sys.base_exec_prefix,
     "prefix": sys.prefix,
+    "base_executable": getattr(sys, "_base_executable", None),
     "sys_executable": sys.executable,
     "sysconfig_paths": sysconfig.get_paths(),
 }

crates/uv-interpreter/src/interpreter.rs

@@ -32,6 +32,7 @@ pub struct Interpreter {
     prefix: PathBuf,
     base_exec_prefix: PathBuf,
     base_prefix: PathBuf,
+    base_executable: Option<PathBuf>,
     sys_executable: PathBuf,
     tags: OnceCell<Tags>,
 }
@@ -54,6 +55,7 @@ impl Interpreter {
             prefix: info.prefix,
             base_exec_prefix: info.base_exec_prefix,
             base_prefix: info.base_prefix,
+            base_executable: info.base_executable,
             sys_executable: info.sys_executable,
             tags: OnceCell::new(),
         })
@@ -77,6 +79,7 @@ impl Interpreter {
             prefix: PathBuf::from("/dev/null"),
             base_exec_prefix: PathBuf::from("/dev/null"),
             base_prefix: PathBuf::from("/dev/null"),
+            base_executable: None,
             sys_executable: PathBuf::from("/dev/null"),
             tags: OnceCell::new(),
         }
@@ -355,6 +358,12 @@ impl Interpreter {
         &self.prefix
     }
 
+    /// Return the `sys._base_executable` path for this Python interpreter. Some platforms do not
+    /// have this attribute, so it may be `None`.
+    pub fn base_executable(&self) -> Option<&Path> {
+        self.base_executable.as_deref()
+    }
+
     /// Return the `sys.executable` path for this Python interpreter.
     pub fn sys_executable(&self) -> &Path {
         &self.sys_executable
@@ -455,6 +464,7 @@ struct InterpreterInfo {
     prefix: PathBuf,
     base_exec_prefix: PathBuf,
     base_prefix: PathBuf,
+    base_executable: Option<PathBuf>,
     sys_executable: PathBuf,
 }
 

crates/uv-virtualenv/src/bare.rs

@@ -48,9 +48,17 @@ pub fn create_bare_venv(
     system_site_packages: bool,
     extra_cfg: Vec<(String, String)>,
 ) -> Result<Virtualenv, Error> {
-    // We have to canonicalize the interpreter path, otherwise the home is set to the venv dir instead of the real root.
-    // This would make python-build-standalone fail with the encodings module not being found because its home is wrong.
-    let base_python = fs_err::canonicalize(interpreter.sys_executable())?;
+    let base_python = if cfg!(unix) {
+        fs_err::canonicalize(interpreter.sys_executable())?
+    } else if cfg!(windows) {
+        if let Some(base_executable) = interpreter.base_executable() {
+            base_executable.to_path_buf()
+        } else {
+            fs_err::canonicalize(interpreter.sys_executable())?
+        }
+    } else {
+        unimplemented!("Only Windows and Unix are supported")
+    };
 
     // Validate the existing location.
     match location.metadata() {