fix: make HarmonyEncoding usable concurrently

the `conversation_has_function_tools` atomic bool makes `HarmonyEncoding` stateful

python/openai_harmony/__init__.py

@@ -425,6 +425,10 @@ class RenderConversationConfig(BaseModel):
     auto_drop_analysis: bool = True
 
 
+class RenderOptions(BaseModel):
+    conversation_has_function_tools: bool = False
+
+
 class HarmonyEncoding:
     """High-level wrapper around the Rust ``PyHarmonyEncoding`` class."""
 
@@ -498,9 +502,20 @@ class HarmonyEncoding:
             config=config_dict,
         )
 
-    def render(self, message: Message) -> List[int]:
+    def render(
+        self, message: Message, render_options: Optional[RenderOptions] = None
+    ) -> List[int]:
         """Render a single message into tokens."""
-        return self._inner.render(message_json=message.to_json())
+        if render_options is None:
+            render_options_dict = {"conversation_has_function_tools": False}
+        else:
+            render_options_dict = {
+                "conversation_has_function_tools": render_options.conversation_has_function_tools
+            }
+
+        return self._inner.render(
+            message_json=message.to_json(), render_options=render_options_dict
+        )
 
     # -- Parsing -------------------------------------------------------
 

src/encoding.rs

@@ -5,10 +5,7 @@ use crate::{
 use anyhow::Context as _;
 use std::{
     collections::{HashMap, HashSet},
-    sync::{
+    sync::Arc,
-        atomic::{AtomicBool, Ordering},
-        Arc,
-    },
     vec,
 };
 
@@ -92,7 +89,6 @@ pub struct HarmonyEncoding {
     pub(crate) format_token_mapping: HashMap<FormattingToken, String>,
     pub(crate) stop_formatting_tokens: HashSet<FormattingToken>,
     pub(crate) stop_formatting_tokens_for_assistant_actions: HashSet<FormattingToken>,
-    pub(crate) conversation_has_function_tools: Arc<AtomicBool>,
 }
 
 impl std::fmt::Debug for HarmonyEncoding {
@@ -191,8 +187,9 @@ impl HarmonyEncoding {
                 }
             })
         });
-        self.conversation_has_function_tools
+        let render_options = RenderOptions {
-            .store(has_function_tools, Ordering::Relaxed);
+            conversation_has_function_tools: has_function_tools,
+        };
         let last_assistant_is_final = messages
             .iter()
             .rev()
@@ -217,9 +214,7 @@ impl HarmonyEncoding {
                     && first_final_idx.is_some_and(|first| *idx < first)
                     && msg.channel.as_deref() == Some("analysis"))
             })
-            .try_for_each(|(_, msg)| self.render_into(msg, into));
+            .try_for_each(|(_, msg)| self.render_into(msg, into, Some(&render_options)));
-        self.conversation_has_function_tools
-            .store(false, Ordering::Relaxed);
         result?;
         Ok(())
     }
@@ -305,18 +300,27 @@ impl HarmonyEncoding {
     }
 
     /// Render a single message into tokens.
-    pub fn render(&self, message: &Message) -> anyhow::Result<Vec<Rank>> {
+    pub fn render(
+        &self,
+        message: &Message,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<Vec<Rank>> {
         let mut out = vec![];
-        Render::<Message>::render(self, message, &mut out)?;
+        Render::<Message>::render(self, message, &mut out, render_options)?;
         Ok(out)
     }
 
     /// Render a single message into the provided buffer.
-    pub fn render_into<B>(&self, message: &Message, into: &mut B) -> anyhow::Result<()>
+    pub fn render_into<B>(
+        &self,
+        message: &Message,
+        into: &mut B,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {
-        Render::<Message>::render(self, message, into)
+        Render::<Message>::render(self, message, into, render_options)
     }
 }
 
@@ -772,14 +776,29 @@ impl HarmonyEncoding {
     }
 }
 
+#[derive(Clone, Copy, Debug, Default)]
+pub struct RenderOptions {
+    pub conversation_has_function_tools: bool,
+}
+
 trait Render<T: ?Sized> {
-    fn render<B>(&self, item: &T, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        item: &T,
+        into: &mut B,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>;
 }
 
 impl Render<Message> for HarmonyEncoding {
-    fn render<B>(&self, message: &Message, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        message: &Message,
+        into: &mut B,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {
@@ -836,7 +855,7 @@ impl Render<Message> for HarmonyEncoding {
                     message.author.role
                 );
             }
-            Render::<Content>::render(self, content, into)?;
+            Render::<Content>::render(self, content, into, render_options)?;
         }
 
         // If there is a tool call we should render a tool call token
@@ -851,15 +870,22 @@ impl Render<Message> for HarmonyEncoding {
 
 // Dispatch Content variants to their specific Render implementations
 impl Render<Content> for HarmonyEncoding {
-    fn render<B>(&self, content: &Content, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        content: &Content,
+        into: &mut B,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {
         match content {
-            Content::Text(text) => Render::<TextContent>::render(self, text, into),
+            Content::Text(text) => Render::<TextContent>::render(self, text, into, render_options),
-            Content::SystemContent(sys) => Render::<SystemContent>::render(self, sys, into),
+            Content::SystemContent(sys) => {
+                Render::<SystemContent>::render(self, sys, into, render_options)
+            }
             Content::DeveloperContent(dev) => {
-                Render::<crate::chat::DeveloperContent>::render(self, dev, into)
+                Render::<crate::chat::DeveloperContent>::render(self, dev, into, render_options)
             }
         }
     }
@@ -867,7 +893,12 @@ impl Render<Content> for HarmonyEncoding {
 
 // Render plain text content
 impl Render<TextContent> for HarmonyEncoding {
-    fn render<B>(&self, text: &TextContent, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        text: &TextContent,
+        into: &mut B,
+        _render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {
@@ -877,7 +908,12 @@ impl Render<TextContent> for HarmonyEncoding {
 
 // Render system-specific content (model identity, instructions, effort)
 impl Render<SystemContent> for HarmonyEncoding {
-    fn render<B>(&self, sys: &SystemContent, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        sys: &SystemContent,
+        into: &mut B,
+        render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {
@@ -923,7 +959,7 @@ impl Render<SystemContent> for HarmonyEncoding {
                 if channel_config.channel_required {
                     channels_header.push_str(" Channel must be included for every message.");
                 }
-                if self.conversation_has_function_tools.load(Ordering::Relaxed) {
+                if render_options.is_some_and(|o| o.conversation_has_function_tools) {
                     channels_header.push('\n');
                     channels_header.push_str(
                         "Calls to these tools must go to the commentary channel: 'functions'.",
@@ -940,7 +976,12 @@ impl Render<SystemContent> for HarmonyEncoding {
 
 // Render developer-specific content (instructions, tools)
 impl Render<crate::chat::DeveloperContent> for HarmonyEncoding {
-    fn render<B>(&self, dev: &crate::chat::DeveloperContent, into: &mut B) -> anyhow::Result<()>
+    fn render<B>(
+        &self,
+        dev: &crate::chat::DeveloperContent,
+        into: &mut B,
+        _render_options: Option<&RenderOptions>,
+    ) -> anyhow::Result<()>
     where
         B: Extend<Rank>,
     {

src/py_module.rs

@@ -178,13 +178,29 @@ impl PyHarmonyEncoding {
     }
 
     /// Render a single message into tokens.
-    fn render(&self, message_json: &str) -> PyResult<Vec<u32>> {
+    fn render(
+        &self,
+        message_json: &str,
+        render_options: Option<Bound<'_, PyDict>>,
+    ) -> PyResult<Vec<u32>> {
         let message: crate::chat::Message = serde_json::from_str(message_json).map_err(|e| {
             PyErr::new::<pyo3::exceptions::PyValueError, _>(format!("invalid message JSON: {e}"))
         })?;
 
+        let rust_options = if let Some(options_dict) = render_options {
+            let conversation_has_function_tools = options_dict
+                .get_item("conversation_has_function_tools")?
+                .and_then(|v| v.extract().ok())
+                .unwrap_or(false);
+            Some(crate::encoding::RenderOptions {
+                conversation_has_function_tools,
+            })
+        } else {
+            None
+        };
+
         self.inner
-            .render(&message)
+            .render(&message, rust_options.as_ref())
             .map_err(|e| PyErr::new::<pyo3::exceptions::PyRuntimeError, _>(e.to_string()))
     }
 

src/registry.rs

@@ -1,6 +1,6 @@
 use std::{
     collections::{HashMap, HashSet},
-    sync::{atomic::AtomicBool, Arc},
+    sync::Arc,
 };
 
 use crate::{
@@ -76,7 +76,6 @@ pub fn load_harmony_encoding(name: HarmonyEncodingName) -> anyhow::Result<Harmon
                     FormattingToken::EndMessageDoneSampling,
                     FormattingToken::EndMessageAssistantToTool,
                 ]),
-                conversation_has_function_tools: Arc::new(AtomicBool::new(false)),
             })
         }
     }

src/tests.rs

@@ -525,7 +525,7 @@ fn test_render_and_render_conversation_roundtrip() {
     let encoding = load_harmony_encoding(HarmonyEncodingName::HarmonyGptOss).unwrap();
     let msg = Message::from_role_and_content(Role::User, "Hello");
     let convo = Conversation::from_messages([msg.clone()]);
-    let tokens_msg = encoding.render(&msg).unwrap();
+    let tokens_msg = encoding.render(&msg, None).unwrap();
     let tokens_convo = encoding.render_conversation(&convo, None).unwrap();
     assert_eq!(tokens_msg, tokens_convo);
     let tokens_completion = encoding

src/wasm_module.rs

@@ -18,6 +18,9 @@ extern "C" {
 
     #[wasm_bindgen(typescript_type = "RenderConversationConfig")]
     pub type JsRenderConversationConfig;
+
+    #[wasm_bindgen(typescript_type = "RenderOptions")]
+    pub type JsRenderOptions;
 }
 
 #[wasm_bindgen(typescript_custom_section)]
@@ -127,12 +130,34 @@ impl JsHarmonyEncoding {
     }
 
     #[wasm_bindgen]
-    pub fn render(&self, message: JsMessage) -> Result<Vec<u32>, JsValue> {
+    pub fn render(
+        &self,
+        message: JsMessage,
+        render_options: JsRenderOptions,
+    ) -> Result<Vec<u32>, JsValue> {
         let message: JsValue = message.into();
         let message: crate::chat::Message = serde_wasm_bindgen::from_value(message)
             .map_err(|e| JsValue::from_str(&format!("invalid message JSON: {e}")))?;
+
+        #[derive(Deserialize)]
+        struct RenderOptions {
+            conversation_has_function_tools: Option<bool>,
+        }
+        let render_options: JsValue = render_options.into();
+        let rust_options = if render_options.is_undefined() || render_options.is_null() {
+            None
+        } else {
+            let cfg: RenderOptions = serde_wasm_bindgen::from_value(render_options)
+                .map_err(|e| JsValue::from_str(&format!("invalid render options: {e}")))?;
+            Some(crate::encoding::RenderOptions {
+                conversation_has_function_tools: cfg
+                    .conversation_has_function_tools
+                    .unwrap_or(false),
+            })
+        };
+
         self.inner
-            .render(&message)
+            .render(&message, rust_options.as_ref())
             .map_err(|e| JsValue::from_str(&e.to_string()))
     }