Simplify contextual user fragment registration (#36742)

## What changed

Replace the type-erased `FragmentRegistration` trait and proxy objects with a
static list of `matches_text` function pointers. Remove the registration types
and their re-exports while preserving the existing contextual fragment matchers.

GitOrigin-RevId: 4e5a296b278984c6e783a67f48fa4bb37646946b

codex-rs/context-fragments/src/fragment.rs

@@ -2,38 +2,6 @@ use codex_protocol::models::ContentItem;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
 
-/// Type-erased registration for a contextual user fragment.
-///
-/// Implementations are used by context filtering code to recognize injected
-/// fragments without constructing the concrete context payload.
-pub trait FragmentRegistration: Sync {
-    fn matches_text(&self, text: &str) -> bool;
-}
-
-pub struct FragmentRegistrationProxy<T> {
-    _marker: std::marker::PhantomData<fn() -> T>,
-}
-
-impl<T> FragmentRegistrationProxy<T> {
-    pub const fn new() -> Self {
-        Self {
-            _marker: std::marker::PhantomData,
-        }
-    }
-}
-
-impl<T> Default for FragmentRegistrationProxy<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T: ContextualUserFragment> FragmentRegistration for FragmentRegistrationProxy<T> {
-    fn matches_text(&self, text: &str) -> bool {
-        T::matches_text(text)
-    }
-}
-
 /// Context payload that is injected as a message fragment.
 ///
 /// Implementations own the response role and provide the exact fragment body.

codex-rs/context-fragments/src/lib.rs

@@ -4,5 +4,3 @@ mod fragment;
 pub use additional_context::AdditionalContextDeveloperFragment;
 pub use additional_context::AdditionalContextUserFragment;
 pub use fragment::ContextualUserFragment;
-pub use fragment::FragmentRegistration;
-pub use fragment::FragmentRegistrationProxy;

codex-rs/core/src/context/contextual_user_message.rs

@@ -3,8 +3,7 @@ use codex_protocol::items::parse_hook_prompt_fragment;
 use codex_protocol::models::ContentItem;
 
 use super::AdditionalContextUserFragment;
-use super::FragmentRegistration;
-use super::FragmentRegistrationProxy;
+use super::ContextualUserFragment;
 use super::InternalModelContextFragment;
 use super::LegacyApplyPatchExecCommandWarning;
 use super::LegacyModelMismatchWarning;
@@ -17,54 +16,25 @@ use super::UserInstructions;
 use super::UserShellCommand;
 use super::world_state::EnvironmentsState;
 
-static USER_INSTRUCTIONS_REGISTRATION: FragmentRegistrationProxy<UserInstructions> =
-    FragmentRegistrationProxy::new();
-static ENVIRONMENT_CONTEXT_REGISTRATION: FragmentRegistrationProxy<EnvironmentsState> =
-    FragmentRegistrationProxy::new();
-static ADDITIONAL_CONTEXT_REGISTRATION: FragmentRegistrationProxy<AdditionalContextUserFragment> =
-    FragmentRegistrationProxy::new();
-static SKILL_INSTRUCTIONS_REGISTRATION: FragmentRegistrationProxy<SkillInstructions> =
-    FragmentRegistrationProxy::new();
-static USER_SHELL_COMMAND_REGISTRATION: FragmentRegistrationProxy<UserShellCommand> =
-    FragmentRegistrationProxy::new();
-static TURN_ABORTED_REGISTRATION: FragmentRegistrationProxy<TurnAborted> =
-    FragmentRegistrationProxy::new();
-static SUBAGENT_NOTIFICATION_REGISTRATION: FragmentRegistrationProxy<SubagentNotification> =
-    FragmentRegistrationProxy::new();
-static INTERNAL_MODEL_CONTEXT_REGISTRATION: FragmentRegistrationProxy<
-    InternalModelContextFragment,
-> = FragmentRegistrationProxy::new();
-static RECOMMENDED_PLUGINS_REGISTRATION: FragmentRegistrationProxy<RecommendedPluginsInstructions> =
-    FragmentRegistrationProxy::new();
-static LEGACY_UNIFIED_EXEC_PROCESS_LIMIT_WARNING_REGISTRATION: FragmentRegistrationProxy<
-    LegacyUnifiedExecProcessLimitWarning,
-> = FragmentRegistrationProxy::new();
-static LEGACY_APPLY_PATCH_EXEC_COMMAND_WARNING_REGISTRATION: FragmentRegistrationProxy<
-    LegacyApplyPatchExecCommandWarning,
-> = FragmentRegistrationProxy::new();
-static LEGACY_MODEL_MISMATCH_WARNING_REGISTRATION: FragmentRegistrationProxy<
-    LegacyModelMismatchWarning,
-> = FragmentRegistrationProxy::new();
-
-static CONTEXTUAL_USER_FRAGMENTS: &[&dyn FragmentRegistration] = &[
-    &USER_INSTRUCTIONS_REGISTRATION,
-    &ENVIRONMENT_CONTEXT_REGISTRATION,
-    &ADDITIONAL_CONTEXT_REGISTRATION,
-    &SKILL_INSTRUCTIONS_REGISTRATION,
-    &USER_SHELL_COMMAND_REGISTRATION,
-    &TURN_ABORTED_REGISTRATION,
-    &SUBAGENT_NOTIFICATION_REGISTRATION,
-    &INTERNAL_MODEL_CONTEXT_REGISTRATION,
-    &RECOMMENDED_PLUGINS_REGISTRATION,
-    &LEGACY_UNIFIED_EXEC_PROCESS_LIMIT_WARNING_REGISTRATION,
-    &LEGACY_APPLY_PATCH_EXEC_COMMAND_WARNING_REGISTRATION,
-    &LEGACY_MODEL_MISMATCH_WARNING_REGISTRATION,
+const CONTEXTUAL_USER_FRAGMENT_MATCHERS: &[fn(&str) -> bool] = &[
+    UserInstructions::matches_text,
+    EnvironmentsState::matches_text,
+    AdditionalContextUserFragment::matches_text,
+    SkillInstructions::matches_text,
+    UserShellCommand::matches_text,
+    TurnAborted::matches_text,
+    SubagentNotification::matches_text,
+    InternalModelContextFragment::matches_text,
+    RecommendedPluginsInstructions::matches_text,
+    LegacyUnifiedExecProcessLimitWarning::matches_text,
+    LegacyApplyPatchExecCommandWarning::matches_text,
+    LegacyModelMismatchWarning::matches_text,
 ];
 
 fn is_standard_contextual_user_text(text: &str) -> bool {
-    CONTEXTUAL_USER_FRAGMENTS
+    CONTEXTUAL_USER_FRAGMENT_MATCHERS
         .iter()
-        .any(|fragment| fragment.matches_text(text))
+        .any(|matches_text| matches_text(text))
 }
 
 pub(crate) fn is_contextual_user_fragment(content_item: &ContentItem) -> bool {

codex-rs/core/src/context/mod.rs

@@ -40,8 +40,6 @@ pub(crate) use available_plugins_instructions::AvailablePluginsInstructions;
 pub(crate) use codex_context_fragments::AdditionalContextDeveloperFragment;
 pub(crate) use codex_context_fragments::AdditionalContextUserFragment;
 pub use codex_context_fragments::ContextualUserFragment;
-pub(crate) use codex_context_fragments::FragmentRegistration;
-pub(crate) use codex_context_fragments::FragmentRegistrationProxy;
 pub(crate) use codex_core_skills::SkillInstructions;
 pub(crate) use contextual_user_message::is_contextual_user_fragment;
 pub(crate) use contextual_user_message::parse_visible_hook_prompt_message;