fix: handle Windows paths

Author: alexeagle

test/unit/extra_outdirs/proc_macro.rs

@@ -4,6 +4,8 @@
 use proc_macro::TokenStream;
 use std::env;
 use std::fs;
+use std::fs::OpenOptions;
+use std::io::Write;
 use std::path::PathBuf;
 
 #[proc_macro]
@@ -16,15 +18,44 @@ pub fn write_to_outdirs(_item: TokenStream) -> TokenStream {
     // Write to the output directories declared by Bazel
     for entry in outdirs_paths.split(',') {
         if let Some((_dir, path)) = entry.split_once(':') {
-            let dir_path = PathBuf::from(path.trim());
+            let path_str = path.trim();
+            // PathBuf will normalize the path correctly for the current platform
+            // On Windows, ensure forward slashes are converted to backslashes
+            let dir_path = if cfg!(windows) {
+                // Convert forward slashes to backslashes for Windows
+                let mut path_buf = PathBuf::from(path_str.replace('/', "\\"));
+                // On Windows, ensure the path is absolute if it's not already
+                if path_buf.is_relative() {
+                    // Try to make it absolute by joining with current directory
+                    if let Ok(current_dir) = std::env::current_dir() {
+                        path_buf = current_dir.join(&path_buf);
+                    }
+                }
+                path_buf
+            } else {
+                PathBuf::from(path_str)
+            };
 
             // Create the directory if it doesn't exist
+            // create_dir_all creates all parent directories as needed
             if let Err(e) = fs::create_dir_all(&dir_path) {
                 panic!("Failed to create directory {}: {:?}", dir_path.display(), e);
             }
             // Write a marker file to ensure the directory is created
+            // Use OpenOptions on Windows to ensure proper file creation
             let marker_file = dir_path.join("marker.txt");
-            if let Err(e) = fs::write(&marker_file, "created by proc-macro") {
+            let result = if cfg!(windows) {
+                // On Windows, use OpenOptions for more explicit control
+                OpenOptions::new()
+                    .create(true)
+                    .write(true)
+                    .truncate(true)
+                    .open(&marker_file)
+                    .and_then(|mut file| file.write_all(b"created by proc-macro"))
+            } else {
+                fs::write(&marker_file, "created by proc-macro")
+            };
+            if let Err(e) = result {
                 panic!(
                     "Failed to write marker file to {}: {:?}",
                     marker_file.display(),