TUI: enforce core boundary (#17399)

Problem: The TUI still depended on `codex-core` directly in a number of
places, and we had no enforcement from keeping this problem from getting
worse.

Solution: Route TUI core access through
`codex-app-server-client::legacy_core`, add CI enforcement for that
boundary, and re-export this legacy bridge inside the TUI as
`crate::legacy_core` so the remaining call sites stay readable. There is
no functional change in this PR — just changes to import targets.

Over time, we can whittle away at the remaining symbols in this legacy
namespace with the eventual goal of removing them all. In the meantime,
this linter rule will prevent us from inadvertently importing new
symbols from core.

codex-rs/tui/src/app.rs

@@ -34,6 +34,16 @@ use crate::history_cell;
 use crate::history_cell::HistoryCell;
 #[cfg(not(debug_assertions))]
 use crate::history_cell::UpdateAvailableHistoryCell;
+use crate::legacy_core::append_message_history_entry;
+use crate::legacy_core::config::Config;
+use crate::legacy_core::config::ConfigBuilder;
+use crate::legacy_core::config::ConfigOverrides;
+use crate::legacy_core::config::edit::ConfigEdit;
+use crate::legacy_core::config::edit::ConfigEditsBuilder;
+use crate::legacy_core::config_loader::ConfigLayerStackOrdering;
+use crate::legacy_core::lookup_message_history_entry;
+#[cfg(target_os = "windows")]
+use crate::legacy_core::windows_sandbox::WindowsSandboxLevelExt;
 use crate::model_catalog::ModelCatalog;
 use crate::model_migration::ModelMigrationOutcome;
 use crate::model_migration::migration_copy_for_models;
@@ -88,16 +98,6 @@ use codex_app_server_protocol::TurnError as AppServerTurnError;
 use codex_app_server_protocol::TurnStatus;
 use codex_config::types::ApprovalsReviewer;
 use codex_config::types::ModelAvailabilityNuxConfig;
-use codex_core::append_message_history_entry;
-use codex_core::config::Config;
-use codex_core::config::ConfigBuilder;
-use codex_core::config::ConfigOverrides;
-use codex_core::config::edit::ConfigEdit;
-use codex_core::config::edit::ConfigEditsBuilder;
-use codex_core::config_loader::ConfigLayerStackOrdering;
-use codex_core::lookup_message_history_entry;
-#[cfg(target_os = "windows")]
-use codex_core::windows_sandbox::WindowsSandboxLevelExt;
 use codex_exec_server::EnvironmentManager;
 use codex_features::Feature;
 use codex_models_manager::collaboration_mode_presets::CollaborationModesConfig;
@@ -321,7 +321,8 @@ fn session_summary(
     thread_name: Option<String>,
 ) -> Option<SessionSummary> {
     let usage_line = (!token_usage.is_zero()).then(|| FinalOutput::from(token_usage).to_string());
-    let resume_command = codex_core::util::resume_command(thread_name.as_deref(), thread_id);
+    let resume_command =
+        crate::legacy_core::util::resume_command(thread_name.as_deref(), thread_id);
 
     if usage_line.is_none() && resume_command.is_none() {
         return None;
@@ -479,7 +480,7 @@ fn emit_project_config_warnings(app_event_tx: &AppEventSender, config: &Config)
 
 fn emit_system_bwrap_warning(app_event_tx: &AppEventSender, config: &Config) {
     let Some(message) =
-        codex_core::config::system_bwrap_warning(config.permissions.sandbox_policy.get())
+        crate::legacy_core::config::system_bwrap_warning(config.permissions.sandbox_policy.get())
     else {
         return;
     };
@@ -1083,7 +1084,7 @@ impl App {
     pub fn chatwidget_init_for_forked_or_resumed_thread(
         &self,
         tui: &mut tui::Tui,
-        cfg: codex_core::config::Config,
+        cfg: crate::legacy_core::config::Config,
     ) -> crate::chatwidget::ChatWidgetInit {
         crate::chatwidget::ChatWidgetInit {
             config: cfg,
@@ -4680,8 +4681,9 @@ impl App {
 
                     // If the elevated setup already ran on this machine, don't prompt for
                     // elevation again - just flip the config to use the elevated path.
-                    if codex_core::windows_sandbox::sandbox_setup_is_complete(codex_home.as_path())
-                    {
+                    if crate::legacy_core::windows_sandbox::sandbox_setup_is_complete(
+                        codex_home.as_path(),
+                    ) {
                         tx.send(AppEvent::EnableWindowsSandboxForAgentMode {
                             preset,
                             mode: WindowsSandboxEnableMode::Elevated,
@@ -4693,7 +4695,7 @@ impl App {
                     self.windows_sandbox.setup_started_at = Some(Instant::now());
                     let session_telemetry = self.session_telemetry.clone();
                     tokio::task::spawn_blocking(move || {
-                        let result = codex_core::windows_sandbox::run_elevated_setup(
+                        let result = crate::legacy_core::windows_sandbox::run_elevated_setup(
                             &policy,
                             policy_cwd.as_path(),
                             command_cwd.as_path(),
@@ -4716,7 +4718,7 @@ impl App {
                                 let mut code_tag: Option<String> = None;
                                 let mut message_tag: Option<String> = None;
                                 if let Some((code, message)) =
-                                    codex_core::windows_sandbox::elevated_setup_failure_details(
+                                    crate::legacy_core::windows_sandbox::elevated_setup_failure_details(
                                         &err,
                                     )
                                 {
@@ -4731,7 +4733,7 @@ impl App {
                                     tags.push(("message", message));
                                 }
                                 session_telemetry.counter(
-                                    codex_core::windows_sandbox::elevated_setup_failure_metric_name(
+                                    crate::legacy_core::windows_sandbox::elevated_setup_failure_metric_name(
                                         &err,
                                     ),
                                     /*inc*/ 1,
@@ -4766,13 +4768,15 @@ impl App {
 
                     self.chat_widget.show_windows_sandbox_setup_status();
                     tokio::task::spawn_blocking(move || {
-                        if let Err(err) = codex_core::windows_sandbox::run_legacy_setup_preflight(
-                            &policy,
-                            policy_cwd.as_path(),
-                            command_cwd.as_path(),
-                            &env_map,
-                            codex_home.as_path(),
-                        ) {
+                        if let Err(err) =
+                            crate::legacy_core::windows_sandbox::run_legacy_setup_preflight(
+                                &policy,
+                                policy_cwd.as_path(),
+                                command_cwd.as_path(),
+                                &env_map,
+                                codex_home.as_path(),
+                            )
+                        {
                             session_telemetry.counter(
                                 "codex.windows_sandbox.legacy_setup_preflight_failed",
                                 /*inc*/ 1,
@@ -4813,7 +4817,7 @@ impl App {
 
                     tokio::task::spawn_blocking(move || {
                         let requested_path = PathBuf::from(path);
-                        let event = match codex_core::grant_read_root_non_elevated(
+                        let event = match crate::legacy_core::grant_read_root_non_elevated(
                             &policy,
                             policy_cwd.as_path(),
                             command_cwd.as_path(),
@@ -5565,7 +5569,7 @@ impl App {
             }
             AppEvent::StatusLineSetup { items } => {
                 let ids = items.iter().map(ToString::to_string).collect::<Vec<_>>();
-                let edit = codex_core::config::edit::status_line_items_edit(&ids);
+                let edit = crate::legacy_core::config::edit::status_line_items_edit(&ids);
                 let apply_result = ConfigEditsBuilder::new(&self.config.codex_home)
                     .with_edits([edit])
                     .apply()
@@ -5591,7 +5595,7 @@ impl App {
             }
             AppEvent::TerminalTitleSetup { items } => {
                 let ids = items.iter().map(ToString::to_string).collect::<Vec<_>>();
-                let edit = codex_core::config::edit::terminal_title_items_edit(&ids);
+                let edit = crate::legacy_core::config::edit::terminal_title_items_edit(&ids);
                 let apply_result = ConfigEditsBuilder::new(&self.config.codex_home)
                     .with_edits([edit])
                     .apply()
@@ -5617,7 +5621,7 @@ impl App {
                 self.chat_widget.cancel_terminal_title_setup();
             }
             AppEvent::SyntaxThemeSelected { name } => {
-                let edit = codex_core::config::edit::syntax_theme_edit(&name);
+                let edit = crate::legacy_core::config::edit::syntax_theme_edit(&name);
                 let apply_result = ConfigEditsBuilder::new(&self.config.codex_home)
                     .with_edits([edit])
                     .apply()
@@ -6340,6 +6344,8 @@ mod tests {
     use crate::multi_agents::AgentPickerThreadEntry;
     use assert_matches::assert_matches;
 
+    use crate::legacy_core::config::ConfigBuilder;
+    use crate::legacy_core::config::ConfigOverrides;
     use codex_app_server_protocol::AdditionalFileSystemPermissions;
     use codex_app_server_protocol::AdditionalNetworkPermissions;
     use codex_app_server_protocol::AdditionalPermissionProfile;
@@ -6380,8 +6386,6 @@ mod tests {
     use codex_app_server_protocol::TurnStatus;
     use codex_app_server_protocol::UserInput as AppServerUserInput;
     use codex_config::types::ModelAvailabilityNuxConfig;
-    use codex_core::config::ConfigBuilder;
-    use codex_core::config::ConfigOverrides;
     use codex_otel::SessionTelemetry;
     use codex_protocol::ThreadId;
     use codex_protocol::config_types::CollaborationMode;
@@ -6711,7 +6715,7 @@ mod tests {
         let thread_id = ThreadId::new();
         let initial_prompt = "follow-up after replay".to_string();
         let config = app.config.clone();
-        let model = codex_core::test_support::get_model_offline(config.model.as_deref());
+        let model = crate::legacy_core::test_support::get_model_offline(config.model.as_deref());
         app.chat_widget = ChatWidget::new_with_app_event(ChatWidgetInit {
             config,
             frame_requester: crate::tui::FrameRequester::test_dummy(),
@@ -9232,7 +9236,7 @@ guardian_approval = true
         let (chat_widget, app_event_tx, _rx, _op_rx) = make_chatwidget_manual_with_sender().await;
         let config = chat_widget.config_ref().clone();
         let file_search = FileSearchManager::new(config.cwd.to_path_buf(), app_event_tx.clone());
-        let model = codex_core::test_support::get_model_offline(config.model.as_deref());
+        let model = crate::legacy_core::test_support::get_model_offline(config.model.as_deref());
         let session_telemetry = test_session_telemetry(&config, model.as_str());
 
         App {
@@ -9286,7 +9290,7 @@ guardian_approval = true
         let (chat_widget, app_event_tx, rx, op_rx) = make_chatwidget_manual_with_sender().await;
         let config = chat_widget.config_ref().clone();
         let file_search = FileSearchManager::new(config.cwd.to_path_buf(), app_event_tx.clone());
-        let model = codex_core::test_support::get_model_offline(config.model.as_deref());
+        let model = crate::legacy_core::test_support::get_model_offline(config.model.as_deref());
         let session_telemetry = test_session_telemetry(&config, model.as_str());
 
         (
@@ -9781,7 +9785,8 @@ guardian_approval = true
     }
 
     fn test_session_telemetry(config: &Config, model: &str) -> SessionTelemetry {
-        let model_info = codex_core::test_support::construct_model_info_offline(model, config);
+        let model_info =
+            crate::legacy_core::test_support::construct_model_info_offline(model, config);
         SessionTelemetry::new(
             ThreadId::new(),
             model,
@@ -9810,7 +9815,7 @@ guardian_approval = true
     }
 
     fn all_model_presets() -> Vec<ModelPreset> {
-        codex_core::test_support::all_model_presets().clone()
+        crate::legacy_core::test_support::all_model_presets().clone()
     }
 
     fn model_availability_nux_config(shown_count: &[(&str, u32)]) -> ModelAvailabilityNuxConfig {