Publish harness and TUI open-source

initial sync from the monorepo

crates/codegen/xai-chat-state/src/conversation_util.rs

@@ -0,0 +1,117 @@
+//! Pure conversation-shape helpers, kept crate-neutral so both the session
+//! layer (`xai-grok-shell`) and the `ChatStateActor` can share one definition
+//! of "align the leading System message with a prompt".
+
+use std::sync::Arc;
+
+use xai_grok_sampling_types::conversation::ConversationItem;
+
+/// Equal after trimming trailing `\n`/`\r` from both sides. Used for attach
+/// idempotency so a stored head that differs from a client override only by a
+/// trailing newline is treated as already matching (cache-friendly no-op).
+/// Interior and leading whitespace are significant.
+pub fn canonical_system_prompt_eq(a: &str, b: &str) -> bool {
+    a.trim_end_matches(['\n', '\r']) == b.trim_end_matches(['\n', '\r'])
+}
+
+/// Replace the leading `System` message with `prompt`, or insert one at the head
+/// if the conversation has no leading `System`. Returns whether the conversation
+/// changed; a head already equal to `prompt` (modulo trailing newlines) is left
+/// untouched for KV-cache-friendly idempotency.
+///
+/// Single source of truth for the "align System[0] with the client override"
+/// operation, shared by the cold-load pre-apply (on a loaded history `Vec`,
+/// before spawn persists it) and the atomic `ChatStateActor` head swap that
+/// backs the resident-reconnect path.
+#[must_use]
+pub fn replace_or_insert_system_head(
+    conversation: &mut Vec<ConversationItem>,
+    prompt: &str,
+) -> bool {
+    match conversation.first_mut() {
+        Some(ConversationItem::System(sys)) => {
+            if canonical_system_prompt_eq(sys.content.as_ref(), prompt) {
+                return false;
+            }
+            sys.content = Arc::from(prompt);
+            true
+        }
+        _ => {
+            conversation.insert(0, ConversationItem::system(prompt));
+            true
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn system_prompt(conversation: &[ConversationItem]) -> Option<&str> {
+        conversation.first().and_then(|item| match item {
+            ConversationItem::System(s) => Some(s.content.as_ref()),
+            _ => None,
+        })
+    }
+
+    #[test]
+    fn canonical_system_prompt_eq_ignores_trailing_newlines() {
+        assert!(canonical_system_prompt_eq("hello\n", "hello"));
+        assert!(canonical_system_prompt_eq("hello\r\n", "hello"));
+        assert!(!canonical_system_prompt_eq("hello", "world"));
+    }
+
+    #[test]
+    fn canonical_system_prompt_eq_respects_interior_and_leading_whitespace() {
+        assert!(canonical_system_prompt_eq("a\nb\n", "a\nb"));
+        assert!(!canonical_system_prompt_eq("a\nb", "ab"));
+        assert!(!canonical_system_prompt_eq(" hello", "hello"));
+    }
+
+    #[test]
+    fn replace_or_insert_system_head_replaces_stored_head() {
+        let mut history = vec![
+            ConversationItem::system("default system prompt"),
+            ConversationItem::user("hi"),
+        ];
+        assert!(replace_or_insert_system_head(
+            &mut history,
+            "client override"
+        ));
+        assert_eq!(system_prompt(&history), Some("client override"));
+        assert_eq!(history.len(), 2, "must not wipe user turns");
+    }
+
+    #[test]
+    fn replace_or_insert_system_head_noop_when_unchanged() {
+        let mut history = vec![
+            ConversationItem::system("same prompt"),
+            ConversationItem::user("hi"),
+        ];
+        assert!(!replace_or_insert_system_head(
+            &mut history,
+            "same prompt\n"
+        ));
+    }
+
+    #[test]
+    fn replace_or_insert_system_head_inserts_when_first_is_not_system() {
+        let mut history = vec![ConversationItem::user("hi")];
+        assert!(replace_or_insert_system_head(
+            &mut history,
+            "client override"
+        ));
+        assert_eq!(system_prompt(&history), Some("client override"));
+        assert_eq!(history.len(), 2, "inserts at head, keeps existing turns");
+    }
+
+    #[test]
+    fn replace_or_insert_system_head_inserts_into_empty() {
+        let mut history: Vec<ConversationItem> = vec![];
+        assert!(replace_or_insert_system_head(
+            &mut history,
+            "client override"
+        ));
+        assert_eq!(system_prompt(&history), Some("client override"));
+    }
+}