Decode the LLM event stream as UTF-8

floatchat/llm.py

@@ -77,7 +77,10 @@ def chat_stream(prompt: str, system: str | None = None, temperature: float = 0.2
         return
     try:
         resp = _post(_payload(prompt, system, temperature, max_tokens, json_mode=False, stream=True), stream=True)
-        for line in resp.iter_lines(decode_unicode=True):
+        # Read bytes and decode as UTF-8: event streams often have no charset, and requests would then fall back to
+        # ISO-8859-1 and garble characters such as "µ" or narrow spaces
+        for raw in resp.iter_lines():
+            line = raw.decode("utf-8", errors="replace") if isinstance(raw, bytes) else raw
             if not line or not line.startswith("data: "):
                 continue
             data = line[len("data: "):]

tests/unit/test_llm.py

@@ -74,6 +74,14 @@ def test_stream_yields_tokens(monkeypatch):
     assert sent[0]["stream"] is True
 
 
+def test_stream_decodes_utf8_bytes(monkeypatch):
+    # Event streams usually carry no charset; the bytes must still be read as UTF-8
+    text = "O₂ minimum 0.8 µmol/kg"
+    line = ("data: " + json.dumps({"choices": [{"delta": {"content": text}}]}, ensure_ascii=False)).encode("utf-8")
+    install(monkeypatch, [FakeResponse(lines=[line, b"data: [DONE]"])])
+    assert "".join(llm.chat_stream("q")) == text
+
+
 def test_stream_yields_nothing_without_an_llm(monkeypatch):
     monkeypatch.setattr(config, "LLM_BASE_URL", "")
     assert list(llm.chat_stream("q")) == []