refactor(php-shim): use std::path::MAIN_SEPARATOR over a shim constant

The shim's DIRECTORY_SEPARATOR was hardcoded to "/", so every ported
`'\\' === DIRECTORY_SEPARATOR` check compared against a constant that
does not track the target platform. std::path::MAIN_SEPARATOR and
MAIN_SEPARATOR_STR carry the same meaning as PHP's constant and resolve
per platform, so the Windows branches are selected on Windows targets.

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

3 files changed, 17 insertions, 27 deletions

diff --git a/crates/shirabe-external-packages/src/symfony/process/executable_finder.rs b/crates/shirabe-external-packages/src/symfony/process/executable_finder.rs
index 3c44b4ad..a00a302c 100644
--- a/crates/shirabe-external-packages/src/symfony/process/executable_finder.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/executable_finder.rs
@@ -25,7 +25,7 @@ impl ExecutableFinder {
 
     pub fn find(&self, name: &str, default: Option<&str>, extra_dirs: &[String]) -> Option<String> {
         // windows built-in commands that are present in cmd.exe should not be resolved using PATH as they do not exist as exes
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\"
+        if std::path::MAIN_SEPARATOR == '\\'
             && CMD_BUILTINS.contains(&shirabe_php_shim::strtolower(name).as_str())
         {
             return Some(name.to_string());
@@ -39,7 +39,7 @@ impl ExecutableFinder {
         dirs.extend_from_slice(extra_dirs);
 
         let mut suffixes: Vec<String> = vec![];
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             let path_ext =
                 shirabe_php_shim::getenv("PATHEXT").map(|v| v.to_string_lossy().into_owned());
             suffixes = self.suffixes.clone();
@@ -68,13 +68,9 @@ impl ExecutableFinder {
         for suffix in &suffixes {
             for dir in &dirs {
                 let dir = if dir.is_empty() { "." } else { dir.as_str() };
-                let file = format!(
-                    "{dir}{}{name}{suffix}",
-                    shirabe_php_shim::DIRECTORY_SEPARATOR
-                );
+                let file = format!("{dir}{}{name}{suffix}", std::path::MAIN_SEPARATOR);
                 if shirabe_php_shim::is_file(&file)
-                    && (shirabe_php_shim::DIRECTORY_SEPARATOR == "\\"
-                        || shirabe_php_shim::is_executable(&file))
+                    && (std::path::MAIN_SEPARATOR == '\\' || shirabe_php_shim::is_executable(&file))
                 {
                     return Some(file);
                 }
@@ -88,12 +84,9 @@ impl ExecutableFinder {
             }
         }
 
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\"
+        if std::path::MAIN_SEPARATOR == '\\'
             || name.len()
-                != shirabe_php_shim::strcspn(
-                    name,
-                    &format!("/{}", shirabe_php_shim::DIRECTORY_SEPARATOR),
-                )
+                != shirabe_php_shim::strcspn(name, &format!("/{}", std::path::MAIN_SEPARATOR))
         {
             return default.map(ToString::to_string);
         }
diff --git a/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs b/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
index 72a28e7d..c4236743 100644
--- a/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
@@ -17,7 +17,7 @@ pub struct WindowsPipes {
 
 impl WindowsPipes {
     pub fn new(_input: PhpMixed) -> Self {
-        // Windows-only path: never constructed on POSIX (DIRECTORY_SEPARATOR is "/").
+        // Windows-only path: never constructed on POSIX (MAIN_SEPARATOR is '/').
         todo!()
     }
 }
diff --git a/crates/shirabe-external-packages/src/symfony/process/process.rs b/crates/shirabe-external-packages/src/symfony/process/process.rs
index 3e4a818f..64ed3a84 100644
--- a/crates/shirabe-external-packages/src/symfony/process/process.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/process.rs
@@ -245,7 +245,7 @@ impl Process {
 
         this.set_input(input)?;
         this.set_timeout(timeout)?;
-        this.use_file_handles = shirabe_php_shim::DIRECTORY_SEPARATOR == "\\";
+        this.use_file_handles = std::path::MAIN_SEPARATOR == '\\';
 
         Ok(this)
     }
@@ -309,7 +309,7 @@ impl Process {
                     .collect::<Vec<_>>()
                     .join(" ");
 
-                if shirabe_php_shim::DIRECTORY_SEPARATOR != "\\" {
+                if std::path::MAIN_SEPARATOR != '\\' {
                     // exec is mandatory to deal with sending a signal to the process
                     cmd = format!("exec {}", cmd);
                 }
@@ -318,7 +318,7 @@ impl Process {
             CommandLine::String(s) => self.replace_placeholders(s, &env)?,
         };
 
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             commandline = self.prepare_windows_command_line(&commandline, &mut env)?;
         } else if !self.use_file_handles && self.is_sigchild_enabled() {
             // last exit code is output on the fourth pipe and caught to work around --enable-sigchild
@@ -414,12 +414,9 @@ impl Process {
         loop {
             self.check_timeout()?;
             let running = self.is_running()
-                && (shirabe_php_shim::DIRECTORY_SEPARATOR == "\\"
+                && (std::path::MAIN_SEPARATOR == '\\'
                     || self.process_pipes.as_ref().unwrap().are_open());
-            self.read_pipes(
-                running,
-                shirabe_php_shim::DIRECTORY_SEPARATOR != "\\" || !running,
-            );
+            self.read_pipes(running, std::path::MAIN_SEPARATOR != '\\' || !running);
             if !running {
                 break;
             }
@@ -644,7 +641,7 @@ impl Process {
 
     /// Enables or disables the TTY mode.
     pub fn set_tty(&mut self, tty: bool) -> anyhow::Result<&mut Self> {
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" && tty {
+        if std::path::MAIN_SEPARATOR == '\\' && tty {
             return Err(RuntimeException::new(
                 "TTY mode is not supported on Windows platform.".to_string(),
             )
@@ -743,7 +740,7 @@ impl Process {
     /// Creates the descriptors needed by the proc_open.
     fn get_descriptors(&mut self) -> Vec<Descriptor> {
         // TODO(plugin): $this->input instanceof \Iterator -> rewind() is not modeled.
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             self.process_pipes = Some(Box::new(WindowsPipes::new(self.input.clone())));
         } else {
             self.process_pipes = Some(Box::new(UnixPipes::new(
@@ -818,7 +815,7 @@ impl Process {
 
         self.read_pipes(
             running && blocking,
-            shirabe_php_shim::DIRECTORY_SEPARATOR != "\\" || !running,
+            std::path::MAIN_SEPARATOR != '\\' || !running,
         );
 
         if !self.fallback_status.is_empty() && self.is_sigchild_enabled() {
@@ -999,7 +996,7 @@ impl Process {
             Some(pid) => pid,
         };
 
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             let mut output: Vec<String> = Vec::new();
             let mut exit_code: i64 = 0;
             shirabe_php_shim::exec(
@@ -1192,7 +1189,7 @@ impl Process {
             None | Some("") => return "\"\"".to_string(),
             Some(a) => a,
         };
-        if shirabe_php_shim::DIRECTORY_SEPARATOR != "\\" {
+        if std::path::MAIN_SEPARATOR != '\\' {
             return format!("'{}'", argument.replace('\'', "'\\''"));
         }
         let mut argument = argument.to_string();