Keep active-turn environments stable across settings updates

codex-rs/core/src/agents_md.rs

@@ -56,7 +56,7 @@ pub(crate) async fn load_project_instructions(
     environments: &TurnEnvironmentSnapshot,
 ) -> Option<LoadedAgentsMd> {
     let mut loaded = LoadedAgentsMd::from_user_instructions(user_instructions);
-    for turn_environment in &environments.turn_environments {
+    for turn_environment in environments.turn_environments() {
         let filesystem = turn_environment.environment.get_filesystem();
         match read_agents_md(
             config,

codex-rs/core/src/agents_md_tests.rs

@@ -2,6 +2,7 @@ use super::*;
 use crate::config::ConfigBuilder;
 use crate::context::ContextualUserFragment;
 use crate::environment_selection::TurnEnvironmentSnapshot;
+use crate::environment_selection::TurnEnvironmentState;
 use crate::session::turn_context::TurnEnvironment;
 use codex_config::ConfigLayerEntry;
 use codex_config::ConfigLayerStack;
@@ -324,10 +325,10 @@ fn resolved_local_environments<const N: usize>(
     environments: [(&str, AbsolutePathBuf); N],
 ) -> TurnEnvironmentSnapshot {
     TurnEnvironmentSnapshot {
-        turn_environments: environments
+        environments: environments
             .into_iter()
             .map(|(environment_id, cwd)| {
-                TurnEnvironment::new(
+                TurnEnvironmentState::Ready(TurnEnvironment::new(
                     environment_id.to_string(),
                     Arc::new(
                         Environment::create_for_tests(/*exec_server_url*/ None)
@@ -336,10 +337,9 @@ fn resolved_local_environments<const N: usize>(
                     PathUri::from_abs_path(&cwd),
                     Vec::new(),
                     /*shell*/ None,
-                )
+                ))
             })
             .collect(),
-        starting: Vec::new(),
     }
 }
 

codex-rs/core/src/codex_delegate_tests.rs

@@ -1,4 +1,5 @@
 use super::*;
+use crate::environment_selection::TurnEnvironmentState;
 use crate::mcp_tool_call::MCP_TOOL_APPROVAL_DECLINE_SYNTHETIC;
 use crate::mcp_tool_call::MCP_TOOL_APPROVAL_QUESTION_ID_PREFIX;
 use async_channel::bounded;
@@ -211,7 +212,11 @@ async fn handle_request_permissions_uses_tool_call_id_for_round_trip() {
         crate::session::tests::make_session_and_context_with_rx().await;
     *parent_session.active_turn.lock().await = Some(crate::state::ActiveTurn::default());
     let parent_ctx_mut = Arc::get_mut(&mut parent_ctx).expect("single turn context ref");
-    parent_ctx_mut.environments.turn_environments[0].environment_id = "remote".to_string();
+    let TurnEnvironmentState::Ready(environment) = &mut parent_ctx_mut.environments.environments[0]
+    else {
+        panic!("expected ready primary environment");
+    };
+    environment.environment_id = "remote".to_string();
 
     let (tx_sub, rx_sub) = bounded(SUBMISSION_CHANNEL_CAPACITY);
     let (_tx_events, rx_events_child) = bounded(SUBMISSION_CHANNEL_CAPACITY);

codex-rs/core/src/context/world_state/environment.rs

@@ -323,8 +323,7 @@ enum EnvironmentStatus {
 
 fn environment_states(snapshot: &TurnEnvironmentSnapshot) -> BTreeMap<String, EnvironmentState> {
     let mut environments = snapshot
-        .turn_environments
-        .iter()
+        .turn_environments()
         .map(|environment| {
             (
                 environment.environment_id.clone(),
@@ -339,7 +338,7 @@ fn environment_states(snapshot: &TurnEnvironmentSnapshot) -> BTreeMap<String, En
             )
         })
         .collect::<BTreeMap<_, _>>();
-    for environment in &snapshot.starting {
+    for environment in snapshot.starting() {
         environments
             .entry(environment.selection.environment_id.clone())
             .or_insert_with(|| EnvironmentState {