From fcd197d5962347db2abc21043b806fb0b560820c Mon Sep 17 00:00:00 2001
From: Michael Bolin <mbolin@openai.com>
Date: Mon, 28 Jul 2025 08:52:18 -0700
Subject: [PATCH] fix: use std::env::args_os instead of std::env::args (#1698)

Apparently `std::env::args()` will panic during iteration if any
argument to the process is not valid Unicode:

https://doc.rust-lang.org/std/env/fn.args.html

Let's avoid the risk and just go with `std::env::args_os()`.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/1698).
* #1705
* #1703
* #1702
* __->__ #1698
* #1697
---
 codex-rs/arg0/src/lib.rs                    | 2 +-
 codex-rs/core/src/mcp_connection_manager.rs | 8 +++++++-
 codex-rs/mcp-client/src/main.rs             | 3 ++-
 codex-rs/mcp-client/src/mcp_client.rs       | 5 +++--
 4 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/codex-rs/arg0/src/lib.rs b/codex-rs/arg0/src/lib.rs
index 86b98c7d..624583b8 100644
--- a/codex-rs/arg0/src/lib.rs
+++ b/codex-rs/arg0/src/lib.rs
@@ -30,7 +30,7 @@ where
     Fut: Future<Output = anyhow::Result<()>>,
 {
     // Determine if we were invoked via the special alias.
-    let argv0 = std::env::args().next().unwrap_or_default();
+    let argv0 = std::env::args_os().next().unwrap_or_default();
     let exe_name = Path::new(&argv0)
         .file_name()
         .and_then(|s| s.to_str())
diff --git a/codex-rs/core/src/mcp_connection_manager.rs b/codex-rs/core/src/mcp_connection_manager.rs
index 886e4f8b..2e33c875 100644
--- a/codex-rs/core/src/mcp_connection_manager.rs
+++ b/codex-rs/core/src/mcp_connection_manager.rs
@@ -8,6 +8,7 @@
 
 use std::collections::HashMap;
 use std::collections::HashSet;
+use std::ffi::OsString;
 use std::time::Duration;
 
 use anyhow::Context;
@@ -127,7 +128,12 @@ impl McpConnectionManager {
 
             join_set.spawn(async move {
                 let McpServerConfig { command, args, env } = cfg;
-                let client_res = McpClient::new_stdio_client(command, args, env).await;
+                let client_res = McpClient::new_stdio_client(
+                    command.into(),
+                    args.into_iter().map(OsString::from).collect(),
+                    env,
+                )
+                .await;
                 match client_res {
                     Ok(client) => {
                         // Initialize the client.
diff --git a/codex-rs/mcp-client/src/main.rs b/codex-rs/mcp-client/src/main.rs
index 8d671b83..10cfe389 100644
--- a/codex-rs/mcp-client/src/main.rs
+++ b/codex-rs/mcp-client/src/main.rs
@@ -10,6 +10,7 @@
 //! program. The utility connects, issues a `tools/list` request and prints the
 //! server's response as pretty JSON.
 
+use std::ffi::OsString;
 use std::time::Duration;
 
 use anyhow::Context;
@@ -37,7 +38,7 @@ async fn main() -> Result<()> {
         .try_init();
 
     // Collect command-line arguments excluding the program name itself.
-    let mut args: Vec<String> = std::env::args().skip(1).collect();
+    let mut args: Vec<OsString> = std::env::args_os().skip(1).collect();
 
     if args.is_empty() || args[0] == "--help" || args[0] == "-h" {
         eprintln!("Usage: mcp-client <program> [args..]\n\nExample: mcp-client codex-mcp-server");
diff --git a/codex-rs/mcp-client/src/mcp_client.rs b/codex-rs/mcp-client/src/mcp_client.rs
index 6a9111e6..084d0bf4 100644
--- a/codex-rs/mcp-client/src/mcp_client.rs
+++ b/codex-rs/mcp-client/src/mcp_client.rs
@@ -12,6 +12,7 @@
 //! issue requests and receive strongly-typed results.
 
 use std::collections::HashMap;
+use std::ffi::OsString;
 use std::sync::Arc;
 use std::sync::atomic::AtomicI64;
 use std::sync::atomic::Ordering;
@@ -82,8 +83,8 @@ impl McpClient {
     /// Caller is responsible for sending the `initialize` request. See
     /// [`initialize`](Self::initialize) for details.
     pub async fn new_stdio_client(
-        program: String,
-        args: Vec<String>,
+        program: OsString,
+        args: Vec<OsString>,
         env: Option<HashMap<String, String>>,
     ) -> std::io::Result<Self> {
         let mut child = Command::new(program)