Split features into codex-features crate (#15253)

- Split the feature system into a new `codex-features` crate.
- Cut `codex-core` and workspace consumers over to the new config and
warning APIs.

Co-authored-by: Ahmed Ibrahim <219906144+aibrahim-oai@users.noreply.github.com>
Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/tests/common/Cargo.toml

@@ -11,7 +11,9 @@ path = "lib.rs"
 anyhow = { workspace = true }
 assert_cmd = { workspace = true }
 base64 = { workspace = true }
+codex-arg0 = { workspace = true }
 codex-core = { workspace = true }
+codex-features = { workspace = true }
 codex-protocol = { workspace = true }
 codex-utils-absolute-path = { workspace = true }
 codex-utils-cargo-bin = { workspace = true }

codex-rs/core/tests/common/lib.rs

@@ -2,8 +2,10 @@
 
 use anyhow::Context as _;
 use anyhow::ensure;
+use codex_arg0::Arg0PathEntryGuard;
 use codex_utils_cargo_bin::CargoBinError;
 use ctor::ctor;
+use std::sync::OnceLock;
 use tempfile::TempDir;
 
 use codex_core::CodexThread;
@@ -24,12 +26,19 @@ pub mod test_codex_exec;
 pub mod tracing;
 pub mod zsh_fork;
 
+static TEST_ARG0_PATH_ENTRY: OnceLock<Option<Arg0PathEntryGuard>> = OnceLock::new();
+
 #[ctor]
 fn enable_deterministic_unified_exec_process_ids_for_tests() {
     codex_core::test_support::set_thread_manager_test_mode(/*enabled*/ true);
     codex_core::test_support::set_deterministic_process_ids(/*enabled*/ true);
 }
 
+#[ctor]
+fn configure_arg0_dispatch_for_test_binaries() {
+    let _ = TEST_ARG0_PATH_ENTRY.get_or_init(codex_arg0::arg0_dispatch);
+}
+
 #[ctor]
 fn configure_insta_workspace_root_for_snapshot_tests() {
     if std::env::var_os("INSTA_WORKSPACE_ROOT").is_some() {
@@ -155,8 +164,7 @@ pub async fn load_default_config_for_test(codex_home: &TempDir) -> Config {
 fn default_test_overrides() -> ConfigOverrides {
     ConfigOverrides {
         codex_linux_sandbox_exe: Some(
-            codex_utils_cargo_bin::cargo_bin("codex-linux-sandbox")
-                .expect("should find binary for codex-linux-sandbox"),
+            find_codex_linux_sandbox_exe().expect("should find binary for codex-linux-sandbox"),
         ),
         ..ConfigOverrides::default()
     }
@@ -167,6 +175,23 @@ fn default_test_overrides() -> ConfigOverrides {
     ConfigOverrides::default()
 }
 
+#[cfg(target_os = "linux")]
+pub fn find_codex_linux_sandbox_exe() -> Result<PathBuf, CargoBinError> {
+    if let Ok(path) = std::env::current_exe() {
+        return Ok(path);
+    }
+
+    if let Some(path) = TEST_ARG0_PATH_ENTRY
+        .get()
+        .and_then(Option::as_ref)
+        .and_then(|path_entry| path_entry.paths().codex_linux_sandbox_exe.clone())
+    {
+        return Ok(path);
+    }
+
+    codex_utils_cargo_bin::cargo_bin("codex-linux-sandbox")
+}
+
 /// Builds an SSE stream body from a JSON fixture.
 ///
 /// The fixture must contain an array of objects where each object represents a
@@ -482,7 +507,7 @@ macro_rules! codex_linux_sandbox_exe_or_skip {
     () => {{
         #[cfg(target_os = "linux")]
         {
-            match codex_utils_cargo_bin::cargo_bin("codex-linux-sandbox") {
+            match $crate::find_codex_linux_sandbox_exe() {
                 Ok(path) => Some(path),
                 Err(err) => {
                     eprintln!("codex-linux-sandbox binary not available, skipping test: {err}");
@@ -498,7 +523,7 @@ macro_rules! codex_linux_sandbox_exe_or_skip {
     ($return_value:expr $(,)?) => {{
         #[cfg(target_os = "linux")]
         {
-            match codex_utils_cargo_bin::cargo_bin("codex-linux-sandbox") {
+            match $crate::find_codex_linux_sandbox_exe() {
                 Ok(path) => Some(path),
                 Err(err) => {
                     eprintln!("codex-linux-sandbox binary not available, skipping test: {err}");

codex-rs/core/tests/common/test_codex.rs

@@ -11,10 +11,10 @@ use codex_core::ModelProviderInfo;
 use codex_core::ThreadManager;
 use codex_core::built_in_model_providers;
 use codex_core::config::Config;
-use codex_core::features::Feature;
 use codex_core::models_manager::collaboration_mode_presets::CollaborationModesConfig;
 use codex_core::shell::Shell;
 use codex_core::shell::get_shell_by_model_provided_path;
+use codex_features::Feature;
 use codex_protocol::config_types::ServiceTier;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::protocol::AskForApproval;

codex-rs/core/tests/common/zsh_fork.rs

@@ -4,7 +4,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use codex_core::config::Config;
 use codex_core::config::Constrained;
-use codex_core::features::Feature;
+use codex_features::Feature;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::SandboxPolicy;