Allow --force to overwrite existing virtualenv (#2548)

## Summary

Closes https://github.com/astral-sh/uv/issues/2529.

## Test Plan

- `mkdir .venv`
- `touch .venv/foo`
- `cargo run venv` (ensure failure)
- `cargo run venv --force` (ensure success)
- `cargo run venv --force` (ensure success again)

crates/uv-virtualenv/src/bare.rs

@@ -47,6 +47,7 @@ pub fn create_bare_venv(
     interpreter: &Interpreter,
     prompt: Prompt,
     system_site_packages: bool,
+    force: bool,
 ) -> Result<Virtualenv, Error> {
     // Determine the base Python executable; that is, the Python executable that should be
     // considered the "base" for the virtual environment. This is typically the Python executable
@@ -88,7 +89,9 @@ pub fn create_bare_venv(
                     format!("File exists at `{}`", location.user_display()),
                 )));
             } else if metadata.is_dir() {
-                if location.join("pyvenv.cfg").is_file() {
+                if force {
+                    info!("Overwriting existing directory");
+                } else if location.join("pyvenv.cfg").is_file() {
                     info!("Removing existing directory");
                     fs::remove_dir_all(location)?;
                     fs::create_dir_all(location)?;
@@ -147,19 +150,17 @@ pub fn create_bare_venv(
     })?;
 
     // Different names for the python interpreter
-    fs::create_dir(&scripts)?;
+    fs::create_dir_all(&scripts)?;
     let executable = scripts.join(format!("python{EXE_SUFFIX}"));
 
     #[cfg(unix)]
     {
-        use fs_err::os::unix::fs::symlink;
-
-        symlink(&base_python, &executable)?;
-        symlink(
+        uv_fs::replace_symlink(&base_python, &executable)?;
+        uv_fs::replace_symlink(
             "python",
             scripts.join(format!("python{}", interpreter.python_major())),
         )?;
-        symlink(
+        uv_fs::replace_symlink(
             "python",
             scripts.join(format!(
                 "python{}.{}",

crates/uv-virtualenv/src/lib.rs

@@ -51,9 +51,10 @@ pub fn create_venv(
     interpreter: Interpreter,
     prompt: Prompt,
     system_site_packages: bool,
+    force: bool,
 ) -> Result<PythonEnvironment, Error> {
     // Create the virtualenv at the given location.
-    let virtualenv = create_bare_venv(location, &interpreter, prompt, system_site_packages)?;
+    let virtualenv = create_bare_venv(location, &interpreter, prompt, system_site_packages, force)?;
 
     // Create the corresponding `PythonEnvironment`.
     let interpreter = interpreter.with_virtualenv(virtualenv);

crates/uv-virtualenv/src/main.rs

@@ -46,6 +46,7 @@ fn run() -> Result<(), uv_virtualenv::Error> {
         &interpreter,
         Prompt::from_args(cli.prompt),
         cli.system_site_packages,
+        false,
     )?;
     Ok(())
 }