golang/go

compress/flate: implement partial flush

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#31,514 opened on Apr 17, 2019

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Description

What version of Go are you using (go version)?

go-1.11.5

while trying to implement zlib compression for SSH (by internal Google request, https://github.com/golang/go/issues/31369), I stumbled on lack of support for partial flush.

partial flush is described more precisely here: https://www.bolet.org/~pornin/deflate-flush.html (look for Z_PARTIAL_FLUSH). While this is deprecated functionality, it has also made its way into the SSH RFC.

For the write side, it looks like I can't truncate the sync marker from a full flush to get the same effect.

For the read side, feeding packets from OpenSSH into zlib.Reader leads to errors ("unexpected EOF").

Contributor guide

Research direction
Study the deflate flush mechanism and implement partial flush as described in the linked article. Ensure both writer and reader handle partial flush correctly.
Tech stack
go
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Gocompress/flate
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40