Avoid erroring when creating `venv` in current working directory (#15537)

## Summary

A strange use-case, but the current behavior is definitely a bug.

Part of https://github.com/astral-sh/uv/issues/15474.

crates/uv-virtualenv/src/virtualenv.rs

@@ -77,6 +77,18 @@ pub(crate) fn create(
         base_python.display()
     );
 
+    // Extract the prompt and compute the absolute path prior to validating the location; otherwise,
+    // we risk deleting (and recreating) the current working directory, which would cause the `CWD`
+    // queries to fail.
+    let prompt = match prompt {
+        Prompt::CurrentDirectoryName => CWD
+            .file_name()
+            .map(|name| name.to_string_lossy().to_string()),
+        Prompt::Static(value) => Some(value),
+        Prompt::None => None,
+    };
+    let absolute = std::path::absolute(location)?;
+
     // Validate the existing location.
     match location.metadata() {
         Ok(metadata) if metadata.is_file() => {
@@ -172,7 +184,8 @@ pub(crate) fn create(
         Err(err) => return Err(Error::Io(err)),
     }
 
-    let location = std::path::absolute(location)?;
+    // Use the absolute path for all further operations.
+    let location = absolute;
 
     let bin_name = if cfg!(unix) {
         "bin"
@@ -182,13 +195,6 @@ pub(crate) fn create(
         unimplemented!("Only Windows and Unix are supported")
     };
     let scripts = location.join(&interpreter.virtualenv().scripts);
-    let prompt = match prompt {
-        Prompt::CurrentDirectoryName => CWD
-            .file_name()
-            .map(|name| name.to_string_lossy().to_string()),
-        Prompt::Static(value) => Some(value),
-        Prompt::None => None,
-    };
 
     // Add the CACHEDIR.TAG.
     cachedir::ensure_tag(&location)?;

crates/uv/tests/it/venv.rs

@@ -1572,3 +1572,26 @@ fn create_venv_nested_symlink_preservation() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn create_venv_current_working_directory() {
+    let context = TestContext::new_with_versions(&["3.12"]);
+
+    uv_snapshot!(context.filters(), context.venv()
+        .arg(".")
+        .arg("--python")
+        .arg("3.12"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Creating virtual environment at: .
+    warning: A directory already exists at `.`. In the future, uv will require `--clear` to replace it
+    Activate with: source bin/activate
+    "
+    );
+
+    context.root.assert(predicates::path::is_dir());
+}