H2

------------------

Bugfixes
~~~~~~~~

- Added debug representations for all events.
- Fixed problems with setup.py that caused trouble on older setuptools/pip
installs.

------------------

API Changes (Backward-Compatible)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

- Added new field to ``DataReceived``: ``flow_controlled_length``. This is the
length of the frame including padded data, allowing users to correctly track
changes to the flow control window.
- Defined new ``UnsupportedFrameError``, thrown when frames that are known to
hyperframe but not supported by hyper-h2 are received. For
backward-compatibility reasons, this is a ``ProtocolError`` *and* a
``KeyError``.

Bugfixes
~~~~~~~~

- Hyper-h2 now correctly accounts for padding when maintaining flow control
windows.
- Resolved a bug where hyper-h2 would mistakenly apply
SETTINGS_INITIAL_WINDOW_SIZE to the connection flow control window in
addition to the stream-level flow control windows.
- Invalid Content-Length headers now throw ``ProtocolError`` exceptions and
correctly tear the connection down, instead of leaving the connection in an
indeterminate state.
- Invalid header blocks now throw ``ProtocolError``, rather than a grab bag of
possible other exceptions.

------------------

API Changes (Breaking)
~~~~~~~~~~~~~~~~~~~~~~

- Attempts to open streams with invalid stream IDs, either by the remote peer
or by the user, are now rejected as a ``ProtocolError``. Previously these
were allowed, and would cause remote peers to error.
- Receiving frames that have invalid padding now causes the connection to be
terminated with a ``ProtocolError`` being raised. Previously these passed
undetected.
- Settings values set by both the user and the remote peer are now validated
when they're set. If they're invalid, a new ``InvalidSettingsValueError`` is
raised and, if set by the remote peer, a connection error is signaled.
Previously, it was possible to set invalid values. These would either be
caught when building frames, or would be allowed to stand.
- Settings changes no longer require user action to be acknowledged: hyper-h2
acknowledges them automatically. This moves the location where some
exceptions may be thrown, and also causes the ``acknowledge_settings`` method
to be removed from the public API.
- Removed a number of methods on the ``H2Connection`` object from the public,
semantically versioned API, by renaming them to have leading underscores.
Specifically, removed:

- ``get_stream_by_id``
- ``get_or_create_stream``
- ``begin_new_stream``
- ``receive_frame``
- ``acknowledge_settings``

- Added full support for receiving CONTINUATION frames, including policing
logic about when and how they are received. Previously, receiving
CONTINUATION frames was not supported and would throw exceptions.
- All public API functions on ``H2Connection`` except for ``receive_data`` no
longer return lists of events, because these lists were always empty. Events
are now only raised by ``receive_data``.
- Calls to ``increment_flow_control_window`` with out of range values now raise
``ValueError`` exceptions. Previously they would be allowed, or would cause
errors when serializing frames.

API Changes (Backward-Compatible)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

- Added ``PriorityUpdated`` event for signaling priority changes.
- Added ``get_next_available_stream_id`` function.
- Receiving DATA frames on streams not in the OPEN or HALF_CLOSED_LOCAL states
now causes a stream reset, rather than a connection reset. The error is now
also classified as a ``StreamClosedError``, rather than a more generic
``ProtocolError``.
- Receiving HEADERS or PUSH_PROMISE frames in the HALF_CLOSED_REMOTE state now
causes a stream reset, rather than a connection reset.
- Receiving frames that violate the max frame size now causes connection errors
with error code FRAME_SIZE_ERROR, not a generic PROTOCOL_ERROR. This
condition now also raises a ``FrameTooLargeError``, a new subclass of
``ProtocolError``.
- Made ``NoSuchStreamError`` a subclass of ``ProtocolError``.
- The ``StreamReset`` event is now also fired whenever a protocol error from
the remote peer forces a stream to close early. This is only fired once.
- The ``StreamReset`` event now carries a flag, ``remote_reset``, that is set
to ``True`` in all cases where ``StreamReset`` would previously have fired
(e.g. when the remote peer sent a RST_STREAM), and is set to ``False`` when
it fires because the remote peer made a protocol error.
- Hyper-h2 now rejects attempts by peers to increment a flow control window by
zero bytes.
- Hyper-h2 now rejects peers sending header blocks that are ill-formed for a
number of reasons as set out in RFC 7540 Section 8.1.2.
- Attempting to send non-PRIORITY frames on closed streams now raises
``StreamClosedError``.
- Remote peers attempting to increase the flow control window beyond
``2**31 - 1``, either by window increment or by settings frame, are now
rejected as ``ProtocolError``.
- Local attempts to increase the flow control window beyond ``2**31 - 1`` by
window increment are now rejected as ``ProtocolError``.
- The bytes that represent individual settings are now available in
``h2.settings``, instead of needing users to import them from hyperframe.

Bugfixes
~~~~~~~~

- RFC 7540 requires that a separate minimum stream ID be used for inbound and
outbound streams. Hyper-h2 now obeys this requirement.
- Hyper-h2 now does a better job of reporting the last stream ID it has
partially handled when terminating connections.
- Fixed an error in the arguments of ``StreamIDTooLowError``.
- Prevent ``ValueError`` leaking from Hyperframe.
- Prevent ``struct.error`` and ``InvalidFrameError`` leaking from Hyperframe.

------------------

Bugfixes
~~~~~~~~

- Forcibly lowercase all header names to improve compatibility with
implementations that demand lower-case header names.

------------------

API Changes (Backward-Compatible)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

- Added a new ``ConnectionTerminated`` event, which fires when GOAWAY frames
are received.
- Added a subclass of ``NoSuchStreamError``, called ``StreamClosedError``, that
fires when actions are taken on a stream that is closed and has had its state
flushed from the system.
- Added ``StreamIDTooLowError``, raised when the user or the remote peer
attempts to create a stream with an ID lower than one previously used in the
dialog. Inherits from ``ValueError`` for backward-compatibility reasons.

Bugfixes
~~~~~~~~

- Do not throw ``ProtocolError`` when attempting to send multiple GOAWAY
frames on one connection.
- We no longer forcefully change the decoder table size when settings changes
are ACKed, instead waiting for remote acknowledgement of the change.
- Improve the performance of checking whether a stream is open.
- We now attempt to lazily garbage collect closed streams, to avoid having the
state hang around indefinitely, leaking memory.
- Avoid further per-stream allocations, leading to substantial performance
improvements when many short-lived streams are used.

------------------

- First production release!