anyio.EndOfStream can leak up

[mcclurem]

Originally raised on httpx, referred here

Discussed in encode/httpx#2848

When using httpx as follows:

async with httpx.AsyncClient(verify=client.verify_ssl) as _client:
        response = await _client.request(**kwargs)

with a misbehaving server I will occasionally get an anyio.EndOfStream exception thrown from deep in the call stack.
I would expect that this should have been caught by httpx and converted into one of the applicable httpx exceptions (probably one of the StreamErrors)

call stack that I see this in:

File "/lib/python3.10/site-packages/httpx/_client.py", line 1530, in request
    return await self.send(request, auth-auth, follow_redirects-follow_redirects)
File "/lib/python3.10/site-packages/httpx/_client.py", line 1617, in send
    response = await self._send_handling_auth
File "/lib/python3.10/site-packages/httpx/_client.py", line 1645, in _send_handling_auth
    response = await self._send_handling_redirects
File "/Users/rack-user/minion_venv/1ib/python3.10/site-packages/httpx/_client.py", line 1682, in _send_handling_redirects
    response = await self._send_single_request (request)
File "/lib/python3.10/site-packages/httpx/_client.py", line 1719, in _send_single_request
    response = await transport. handle_async_request(request)
File "/Users/rack-user/minion_venv/lib/python3.10/site-packages/httpx/_transports/default.py", line 353, in handle_async_request
    resp = await self._pool.handle_async_request(reg)
File "/lib/python3.10/site-packages/httpcore/_async/connection_pool.py", line 262, in handle_async_request
    raise exc
File "/lib/python3.10/site-packages/httpcore/_async/connection_pool.py", line 245, in handle_async_request
    response = await connection.handle_async_request(request)
File "/lib/python3.10/site-packages/httpcore/_async/connection.py", line 92, in handle_async_request
    raise exc
File "/lib/python3.10/site-packages/httpcore/_async/connection.py", line 69, in handle_async_request
    stream = await self._connect(request)
File "/lib/python3.10/site-packages/httpcore/_async/connection.py", line 149, in _connect
    stream = await stream.start_tls(**kwargs)
File "/Users/rack_user/minion-venv/lib/python3.10/site-packages/httpcore/_backends/anyio.py", line 78, in start_tls
    raise exc
File "/lib/python3.10/site-packages/httpcore/_backends/anyio.py", line 69, in start_tls
ssl_stream = await anyio.streams.tls.TLSStream.wrap(
File "/lib/python3.10/site-packages/anyio/streams/tls.py", line 125, in wrap
    await wrapper._call_sslobject_method(ss1_object.do_handshake)
File "/lib/python3.10/site-packages/anyio/streams/tls.py", line 165, in _call_sslobject_method
    raise EndOfStream from None

[karpetrosyan]

It seems like we should just add the new exception mapping to the anyio backend module.

EndOfStream class definition:

class EndOfStream(Exception):
    """Raised when trying to read from a stream that has been closed from the other end."""

I believe it would be sufficient to add EndOfStream mapping with ReadError here.

httpcore/httpcore/_backends/anyio.py

Lines 62 to 65 in 6071ea7

	exc_map = {
	TimeoutError: ConnectTimeout,
	anyio.BrokenResourceError: ConnectError,
	}

and here

httpcore/httpcore/_backends/anyio.py

Lines 26 to 30 in 6071ea7

	exc_map = {
	TimeoutError: ReadTimeout,
	anyio.BrokenResourceError: ReadError,
	anyio.ClosedResourceError: ReadError,
	}

[tomchristie]

For bonus points...

• Which exceptions does anyio document may be raised in each circumstance? If a pull request here can reference the anyio docs then we'll have good interlinking, and be confident that we've correctly covered the various possible exception cases. I dug into this from a quick look, but haven't comprehensively listed out which exceptions could be raised from each of our stream operations.
• Can you demo the issue in the most isolated case possible, by working with just the network backend API? Being able to show a case where the exception is raised just using .connect_tcp() and .start_tls() would show that we've properly isolated the issue. (I know we have, but it'd be a neat wrapping up.) Do our docs properly indicate which exceptions may be raised by the network backend operations?

[PrathamSoni]

Hi! Were there any updates to this?

[tomchristie]

This is still up for grabs, pull requests welcome. 🤗

@karpetrosyan's comment above points to where we need a couple of entries adding in our exception mapping.

[jakekaplan]

Really glad to see this issue is closed 🙌!

Any idea when the next release will be that includes this?

[seano314]

Really glad to see this issue is closed 🙌!

Any idea when the next release will be that includes this?

Agree completely and would love to know the answer to this question too :)

[tomchristie]

Welcome to issue a release PR.

For example, see... #892

[okba-boularaoui]

Thank you @tomchristie, Version 1.0.5 (#904) PR is ready for review.