Fix HTTP/2 send when flow-control window is negative - #1083
Open
mbeijen wants to merge 1 commit into
Open
Conversation
`_wait_for_outgoing_flow` previously waited only while the available
flow was exactly zero. Per RFC 7540 §6.9.2, when a peer sends a SETTINGS
frame that reduces INITIAL_WINDOW_SIZE, every existing stream send
window is adjusted by the delta and may become negative. With the
`while flow == 0` guard, a negative window passed straight through and
h2 raised `LocalProtocolError("Cannot send N bytes, flow control window
is -M")` on the next send_data call.
Switching the guard to `while flow <= 0` keeps the stream parked until
WINDOW_UPDATE frames restore positive credit.
Refs: encode#1082
Refs: encode/httpx#3601
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
注册 for free
to join this conversation on GitHub.
Already have an account?
登录 to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
_wait_for_outgoing_flowpreviously waited only while the available flow was exactly zero. Per RFC 7540 §6.9.2, when a peer sends a SETTINGS frame that reduces INITIAL_WINDOW_SIZE, every existing stream send window is adjusted by the delta and may become negative. With thewhile flow == 0guard, a negative window passed straight through and h2 raisedLocalProtocolError("Cannot send N bytes, flow control window is -M")on the next send_data call.Switching the guard to
while flow <= 0keeps the stream parked until WINDOW_UPDATE frames restore positive credit.Refs: #1082
Refs: encode/httpx#3601
Checklist