feat: Adapt to new protocol buffer message schema

Adapt to httpstan's new protobuf message schema.
See commit 91964cb073635cd07d38617fdeb6d3f3815fe3eb in
httpstan.

The protocol buffer message now uses protocol buffers `bytes` types
where previously protocol buffers `string` types were used.

pyproject.toml

@@ -23,7 +23,7 @@ classifiers = [
 [tool.poetry.dependencies]
 python = "^3.7"
 aiohttp = "^3.6"
-httpstan = "^2.3.0"
+httpstan = "^3.0.0"
 numpy = "^1.7"
 clikit = "^0.6.2"
 

stan/fit.py

@@ -66,14 +66,14 @@ def __init__(
             for msg in stan_output:
                 if msg.topic == callbacks_writer_pb2.WriterMessage.Topic.Value("SAMPLE"):
                     # Ignore sample message which is mixed together with proper draws.
-                    if msg.feature and msg.feature[0].name == "":
+                    if msg.feature and msg.feature[0].name == b"":
                         continue
 
                     draw_row = []  # a "row" of values from a single draw from Stan C++
 
                     # for the first draw: collect sample and sampler parameter names.
                     if not hasattr(self, "_draws"):
-                        feature_names = tuple(fea.name for fea in msg.feature)
+                        feature_names = tuple(fea.name.decode() for fea in msg.feature)
                         self.sample_and_sampler_param_names = tuple(
                             name for name in feature_names if name.endswith("__")
                         )

stan/model.py

@@ -192,17 +192,17 @@ async def go():
                 def is_nonempty_logger_message(msg):
                     return (
                         msg.topic == callbacks_writer_pb2.WriterMessage.Topic.LOGGER
-                        and msg.feature[0].string_list.value[0].strip() != "info:"
+                        and msg.feature[0].bytes_list.value[0].strip() != b"info:"
                     )
 
                 def is_iteration_or_elapsed_time_logger_message(msg):
                     # Assumes `msg` is a message with topic `LOGGER`.
-                    text = msg.feature[0].string_list.value[0]
+                    text = msg.feature[0].bytes_list.value[0]
                     return (
-                        text.startswith("info:Iteration:")
-                        or text.startswith("info: Elapsed Time:")
+                        text.startswith(b"info:Iteration:")
+                        or text.startswith(b"info: Elapsed Time:")
                         # this detects lines following "Elapsed Time:", part of a multi-line Stan message
-                        or text.startswith("info:" + " " * 15)
+                        or text.startswith(b"info:" + b" " * 15)
                     )
 
                 logger_messages = []
@@ -216,8 +216,8 @@ def is_iteration_or_elapsed_time_logger_message(msg):
                 if non_standard_logger_messages:
                     io.error("\n<info>Messages received during sampling:</info>\n")
                     for msg in non_standard_logger_messages:
-                        text = msg.feature[0].string_list.value[0].replace("info:", "  ")
-                        io.error(f"<info>{text}</info>\n")
+                        text_bytes = msg.feature[0].bytes_list.value[0].replace(b"info:", b"  ")
+                        io.error(f"<info>{text_bytes.decode()}</info>\n")
 
                 # clean up after ourselves when fit is uncacheable (no random seed)
                 if self.random_seed is None: