Revert "perf: stop generation on default turn boundaries"

This reverts commit caf4654c0a2a856c8f71dd465d4a4b1d67cde5bc.

crates/inference-server/src/compat.rs

@@ -514,17 +514,7 @@ pub fn build_sampler(req: &ChatCompletionRequest) -> inference_core::SamplerConf
     sampler.temperature = req.temperature.clamp(0.0, 2.0);
     sampler.top_p = req.top_p.clamp(0.0, 1.0);
     sampler.max_tokens = req.max_tokens.max(1);
-    sampler.stop_sequences = if req.stop.is_empty() {
-        vec![
-            "\nUser:".to_owned(),
-            "\nSystem:".to_owned(),
-            "\nDeveloper:".to_owned(),
-            "\nAssistant:".to_owned(),
-            "\nTool:".to_owned(),
-        ]
-    } else {
-        req.stop.clone()
-    };
+    sampler.stop_sequences = req.stop.clone();
     sampler.repeat_penalty = if req.tools.is_empty() { 1.05 } else { 1.0 };
     sampler.seed = req.seed.unwrap_or(0);
     sampler
@@ -575,8 +565,8 @@ pub fn ensure_supported_mode(req: &ChatCompletionRequest) -> Result<()> {
 #[cfg(test)]
 mod tests {
     use super::{
-        authorize_request, build_sampler, finalize_assistant_message, prepare_prompt,
-        validate_request, FinalizedAssistant, ModelCatalog, ServerConfig, StreamingMode,
+        authorize_request, finalize_assistant_message, prepare_prompt, validate_request,
+        FinalizedAssistant, ModelCatalog, ServerConfig, StreamingMode,
     };
     use api_contracts::chat::ChatCompletionRequest;
     use axum::http::{HeaderMap, HeaderValue, StatusCode};
@@ -728,18 +718,4 @@ mod tests {
             Some("Use references and lifetimes.")
         );
     }
-
-    #[test]
-    fn adds_default_turn_stops_when_request_has_none() {
-        let request = parse_request(
-            r#"{
-                "model": "alias-model",
-                "messages": [{"role":"user","content":"hi"}]
-            }"#,
-        );
-
-        let sampler = build_sampler(&request);
-        assert!(sampler.stop_sequences.contains(&"\nUser:".to_owned()));
-        assert!(sampler.stop_sequences.contains(&"\nAssistant:".to_owned()));
-    }
 }