refactor(path): build paths with Path::join

Concatenating a directory, MAIN_SEPARATOR and a component reimplements
what Path::join already does. Joining directly also drops the separator
from the intermediate values it used to be baked into, such as
ClassLoader's $pathEnd.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

5 files changed, 46 insertions, 35 deletions

diff --git a/crates/shirabe/src/autoload/class_loader.rs b/crates/shirabe/src/autoload/class_loader.rs
index 21473fb9..023812ce 100644
--- a/crates/shirabe/src/autoload/class_loader.rs
+++ b/crates/shirabe/src/autoload/class_loader.rs
@@ -383,13 +383,13 @@ impl ClassLoader {
                 sub_path = substr(&sub_path, 0, Some(last_pos as i64));
                 let search = format!("{}\\", sub_path);
                 if let Some(dirs) = self.prefix_dirs_psr4.get(&search) {
-                    let path_end = format!(
-                        "{}{}",
-                        std::path::MAIN_SEPARATOR,
-                        substr(&logical_path_psr4, (last_pos + 1) as i64, None)
-                    );
+                    let path_end = substr(&logical_path_psr4, (last_pos + 1) as i64, None);
                     for dir in dirs {
-                        let file = format!("{}{}", dir, path_end);
+                        let file = std::path::Path::new(dir)
+                            .join(&path_end)
+                            .into_os_string()
+                            .into_string()
+                            .unwrap();
                         if file_exists(&file) {
                             return Some(file);
                         }
@@ -400,7 +400,11 @@ impl ClassLoader {
 
         // PSR-4 fallback dirs
         for dir in &self.fallback_dirs_psr4 {
-            let file = format!("{}{}{}", dir, std::path::MAIN_SEPARATOR, logical_path_psr4);
+            let file = std::path::Path::new(dir)
+                .join(&logical_path_psr4)
+                .into_os_string()
+                .into_string()
+                .unwrap();
             if file_exists(&file) {
                 return Some(file);
             }
@@ -432,8 +436,11 @@ impl ClassLoader {
             for (prefix, dirs) in prefixes {
                 if Some(0) == strpos(class, prefix) {
                     for dir in dirs {
-                        let file =
-                            format!("{}{}{}", dir, std::path::MAIN_SEPARATOR, logical_path_psr0);
+                        let file = std::path::Path::new(dir)
+                            .join(&logical_path_psr0)
+                            .into_os_string()
+                            .into_string()
+                            .unwrap();
                         if file_exists(&file) {
                             return Some(file);
                         }
@@ -444,7 +451,11 @@ impl ClassLoader {
 
         // PSR-0 fallback dirs
         for dir in &self.fallback_dirs_psr0 {
-            let file = format!("{}{}{}", dir, std::path::MAIN_SEPARATOR, logical_path_psr0);
+            let file = std::path::Path::new(dir)
+                .join(&logical_path_psr0)
+                .into_os_string()
+                .into_string()
+                .unwrap();
             if file_exists(&file) {
                 return Some(file);
             }
diff --git a/crates/shirabe/src/command/create_project_command.rs b/crates/shirabe/src/command/create_project_command.rs
index 3849d93d..048d7b59 100644
--- a/crates/shirabe/src/command/create_project_command.rs
+++ b/crates/shirabe/src/command/create_project_command.rs
@@ -458,12 +458,11 @@ impl CreateProjectCommand {
         let mut directory = match directory {
             None => {
                 let mut parts = explode_with_limit("/", &name, 2);
-                format!(
-                    "{}{}{}",
-                    Platform::get_cwd(false)?,
-                    std::path::MAIN_SEPARATOR,
-                    array_pop(&mut parts).unwrap_or_default()
-                )
+                std::path::Path::new(&Platform::get_cwd(false)?)
+                    .join(array_pop(&mut parts).unwrap_or_default())
+                    .into_os_string()
+                    .into_string()
+                    .unwrap()
             }
             Some(directory) => directory,
         };
@@ -474,12 +473,11 @@ impl CreateProjectCommand {
         ))));
         let fs = std::rc::Rc::new(std::cell::RefCell::new(Filesystem::new(Some(process))));
         if !fs.borrow().is_absolute_path(&directory) {
-            directory = format!(
-                "{}{}{}",
-                Platform::get_cwd(false)?,
-                std::path::MAIN_SEPARATOR,
-                directory
-            );
+            directory = std::path::Path::new(&Platform::get_cwd(false)?)
+                .join(&directory)
+                .into_os_string()
+                .into_string()
+                .unwrap();
         }
         if directory.is_empty() {
             return Err(UnexpectedValueException::new(
diff --git a/crates/shirabe/src/downloader/gzip_downloader.rs b/crates/shirabe/src/downloader/gzip_downloader.rs
index 3ddca2a4..962c5bb8 100644
--- a/crates/shirabe/src/downloader/gzip_downloader.rs
+++ b/crates/shirabe/src/downloader/gzip_downloader.rs
@@ -90,7 +90,11 @@ impl ArchiveDownloader for GzipDownloader {
             .unwrap_or(""),
             PATHINFO_FILENAME,
         );
-        let target_filepath = format!("{}{}{}", path, std::path::MAIN_SEPARATOR, filename);
+        let target_filepath = std::path::Path::new(path)
+            .join(&filename)
+            .into_os_string()
+            .into_string()
+            .unwrap();
 
         if !Platform::is_windows() {
             let command = vec![
diff --git a/crates/shirabe/src/downloader/path_downloader.rs b/crates/shirabe/src/downloader/path_downloader.rs
index 4be835cd..6a496c6a 100644
--- a/crates/shirabe/src/downloader/path_downloader.rs
+++ b/crates/shirabe/src/downloader/path_downloader.rs
@@ -380,12 +380,11 @@ impl DownloaderInterface for PathDownloader {
                         {
                             let absolute_path =
                                 if !self.inner.filesystem.borrow_mut().is_absolute_path(&path) {
-                                    format!(
-                                        "{}{}{}",
-                                        Platform::get_cwd(false)?,
-                                        std::path::MAIN_SEPARATOR,
-                                        path
-                                    )
+                                    std::path::Path::new(&Platform::get_cwd(false)?)
+                                        .join(&path)
+                                        .into_os_string()
+                                        .into_string()
+                                        .unwrap()
                                 } else {
                                     path.clone()
                                 };
diff --git a/crates/shirabe/src/util/filesystem.rs b/crates/shirabe/src/util/filesystem.rs
index a12c6d64..2c4cbcc6 100644
--- a/crates/shirabe/src/util/filesystem.rs
+++ b/crates/shirabe/src/util/filesystem.rs
@@ -488,12 +488,11 @@ impl Filesystem {
 
         let mut result = true;
         for file in &ri {
-            let target_path = format!(
-                "{}{}{}",
-                target,
-                std::path::MAIN_SEPARATOR,
-                ri.get_sub_pathname()
-            );
+            let target_path = Path::new(&target)
+                .join(ri.get_sub_pathname())
+                .into_os_string()
+                .into_string()
+                .unwrap();
             if file.is_dir() {
                 self.ensure_directory_exists(&target_path)?;
             } else {