Refactor env settings into config (#1601)

## Summary
- add OpenAI retry and timeout fields to Config
- inject these settings in tests instead of mutating env vars
- plumb Config values through client and chat completions logic
- document new configuration options

## Testing
- `cargo test -p codex-core --no-run`

------
https://chatgpt.com/codex/tasks/task_i_68792c5b04cc832195c03050c8b6ea94

---------

Co-authored-by: Michael Bolin <mbolin@openai.com>

codex-rs/core/tests/cli_stream.rs

@@ -173,7 +173,7 @@ async fn integration_creates_and_checks_session_file() {
     // 5. Sessions are written asynchronously; wait briefly for the directory to appear.
     let sessions_dir = home.path().join("sessions");
     let start = Instant::now();
-    while !sessions_dir.exists() && start.elapsed() < Duration::from_secs(2) {
+    while !sessions_dir.exists() && start.elapsed() < Duration::from_secs(3) {
         std::thread::sleep(Duration::from_millis(50));
     }
 

codex-rs/core/tests/client.rs

@@ -49,13 +49,6 @@ async fn includes_session_id_and_model_headers_in_request() {
         .mount(&server)
         .await;
 
-    // Environment
-    // Update environment – `set_var` is `unsafe` starting with the 2024
-    // edition so we group the calls into a single `unsafe { … }` block.
-    unsafe {
-        std::env::set_var("OPENAI_REQUEST_MAX_RETRIES", "0");
-        std::env::set_var("OPENAI_STREAM_MAX_RETRIES", "0");
-    }
     let model_provider = ModelProviderInfo {
         name: "openai".into(),
         base_url: format!("{}/v1", server.uri()),
@@ -72,6 +65,9 @@ async fn includes_session_id_and_model_headers_in_request() {
                 .collect(),
         ),
         env_http_headers: None,
+        request_max_retries: Some(0),
+        stream_max_retries: Some(0),
+        stream_idle_timeout_ms: None,
     };
 
     // Init session

codex-rs/core/tests/live_agent.rs

@@ -45,22 +45,10 @@ async fn spawn_codex() -> Result<Codex, CodexErr> {
         "OPENAI_API_KEY must be set for live tests"
     );
 
-    // Environment tweaks to keep the tests snappy and inexpensive while still
-    // exercising retry/robustness logic.
-    //
-    // NOTE: Starting with the 2024 edition `std::env::set_var` is `unsafe`
-    // because changing the process environment races with any other threads
-    // that might be performing environment look-ups at the same time.
-    // Restrict the unsafety to this tiny block that happens at the very
-    // beginning of the test, before we spawn any background tasks that could
-    // observe the environment.
-    unsafe {
-        std::env::set_var("OPENAI_REQUEST_MAX_RETRIES", "2");
-        std::env::set_var("OPENAI_STREAM_MAX_RETRIES", "2");
-    }
-
     let codex_home = TempDir::new().unwrap();
-    let config = load_default_config_for_test(&codex_home);
+    let mut config = load_default_config_for_test(&codex_home);
+    config.model_provider.request_max_retries = Some(2);
+    config.model_provider.stream_max_retries = Some(2);
     let (agent, _init_id) = Codex::spawn(config, std::sync::Arc::new(Notify::new())).await?;
 
     Ok(agent)
@@ -79,7 +67,7 @@ async fn live_streaming_and_prev_id_reset() {
 
     let codex = spawn_codex().await.unwrap();
 
-    // ---------- Task 1 ----------
+    // ---------- Task 1 ----------
     codex
         .submit(Op::UserInput {
             items: vec![InputItem::Text {
@@ -113,7 +101,7 @@ async fn live_streaming_and_prev_id_reset() {
         "Agent did not stream any AgentMessage before TaskComplete"
     );
 
-    // ---------- Task 2 (same session) ----------
+    // ---------- Task 2 (same session) ----------
     codex
         .submit(Op::UserInput {
             items: vec![InputItem::Text {

codex-rs/core/tests/previous_response_id.rs

@@ -88,13 +88,8 @@ async fn keeps_previous_response_id_between_tasks() {
         .mount(&server)
         .await;
 
-    // Environment
-    // Update environment – `set_var` is `unsafe` starting with the 2024
-    // edition so we group the calls into a single `unsafe { … }` block.
-    unsafe {
-        std::env::set_var("OPENAI_REQUEST_MAX_RETRIES", "0");
-        std::env::set_var("OPENAI_STREAM_MAX_RETRIES", "0");
-    }
+    // Configure retry behavior explicitly to avoid mutating process-wide
+    // environment variables.
     let model_provider = ModelProviderInfo {
         name: "openai".into(),
         base_url: format!("{}/v1", server.uri()),
@@ -107,6 +102,10 @@ async fn keeps_previous_response_id_between_tasks() {
         query_params: None,
         http_headers: None,
         env_http_headers: None,
+        // disable retries so we don't get duplicate calls in this test
+        request_max_retries: Some(0),
+        stream_max_retries: Some(0),
+        stream_idle_timeout_ms: None,
     };
 
     // Init session

codex-rs/core/tests/stream_no_completed.rs

@@ -32,8 +32,6 @@ fn sse_completed(id: &str) -> String {
 }
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-// this test is flaky (has race conditions), so we ignore it for now
-#[ignore]
 async fn retries_on_early_close() {
     #![allow(clippy::unwrap_used)]
 
@@ -72,19 +70,8 @@ async fn retries_on_early_close() {
         .mount(&server)
         .await;
 
-    // Environment
-    //
-    // As of Rust 2024 `std::env::set_var` has been made `unsafe` because
-    // mutating the process environment is inherently racy when other threads
-    // are running.  We therefore have to wrap every call in an explicit
-    // `unsafe` block.  These are limited to the test-setup section so the
-    // scope is very small and clearly delineated.
-
-    unsafe {
-        std::env::set_var("OPENAI_REQUEST_MAX_RETRIES", "0");
-        std::env::set_var("OPENAI_STREAM_MAX_RETRIES", "1");
-        std::env::set_var("OPENAI_STREAM_IDLE_TIMEOUT_MS", "2000");
-    }
+    // Configure retry behavior explicitly to avoid mutating process-wide
+    // environment variables.
 
     let model_provider = ModelProviderInfo {
         name: "openai".into(),
@@ -98,6 +85,10 @@ async fn retries_on_early_close() {
         query_params: None,
         http_headers: None,
         env_http_headers: None,
+        // exercise retry path: first attempt yields incomplete stream, so allow 1 retry
+        request_max_retries: Some(0),
+        stream_max_retries: Some(1),
+        stream_idle_timeout_ms: Some(2000),
     };
 
     let ctrl_c = std::sync::Arc::new(tokio::sync::Notify::new());