Transport errors while consuming a stream escape as raw httpx exceptions instead of APITimeoutError / APIConnectionError #1919

import platform
import sys

import anthropic

try:
    import httpx2 as httpx  # anthropic >= 1.0
except ImportError:
    import httpx

FIRST = b'event: message_start\ndata: {"type":"message_start","message":{"id":"msg_1","type":"message","role":"assistant","model":"claude-sonnet-4-6","content":[],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":1,"output_tokens":0}}}\n\n'
requests_seen = 0


class DiesMidStream(httpx.SyncByteStream):
    def __iter__(self):
        yield FIRST
        raise httpx.ReadTimeout("timed out while reading the stream")


def handler(request: httpx.Request) -> httpx.Response:
    global requests_seen
    requests_seen += 1
    return httpx.Response(200, headers={"content-type": "text/event-stream"}, stream=DiesMidStream())


client = anthropic.Anthropic(
    api_key="x", http_client=httpx.Client(transport=httpx.MockTransport(handler)), max_retries=2
)
print(f"python {sys.version.split()[0]} {platform.system()}, anthropic {anthropic.__version__}, httpx {httpx.__version__}")
try:
    with client.messages.stream(model="claude-sonnet-4-6", max_tokens=8, messages=[{"role": "user", "content": "hi"}]) as s:
        for _ in s:
            pass
except Exception as e:  # noqa: BLE001
    print(f"escaped: {type(e).__module__}.{type(e).__name__}: {e}")
    print(f"isinstance(e, anthropic.APIError) = {isinstance(e, anthropic.APIError)}")
print(f"requests made with max_retries=2: {requests_seen}")