[PATCH 0/6] Refactor fetch negotiation into its own API

Both Stefan and Junio have suggested in [1] that I create a new negotiation API first, then implement a new algorithm, and I perhaps too optimistically said that doing it all at once should be fine. Extracting the API turns out to be more difficult than expected. Here are the patches that do that, without any new algorithms.

The patches include 3 patches that eliminate some minor differences between protocol v0 and protocol v2, then 3 patches that implement the API. I tried to write tests for all of the former 3, but could only do so for one, because I didn't know how to construct situations that show a difference in behavior as an effect of such a code change (or, if such a situation is possible without custom transports). As for the latter 3, these are refactorings with no user-visible changes, and I have tried to write them in such a way that it is clear to a reviewer that the same functionality and logic is present before and after, and that they are just organized better.

Overall, these do not change much functionality, but would be a good base for contributors (myself and even others) to experiment with negotiation algorithms.

[1] https://public-inbox.org/git/20180521204340.260572-1-jonathantanmy@google.com/

Jonathan Tan (6):
  fetch-pack: clear marks before everything_local()
  fetch-pack: truly stop negotiation upon ACK ready
  fetch-pack: in protocol v2, enqueue commons first
  fetch-pack: make negotiation-related vars local
  fetch-pack: move common check and marking together
  fetch-pack: introduce negotiator API

 Makefile              |   2 +
 fetch-negotiator.c    |   7 ++
 fetch-negotiator.h    |  45 +++++++++
 fetch-pack.c          | 222 ++++++++++++------------------------------
 negotiator/default.c  | 173 ++++++++++++++++++++++++++++++++
 negotiator/default.h  |   8 ++
 object.h              |   3 +-
 t/t5500-fetch-pack.sh |  35 +++++++
 8 files changed, 332 insertions(+), 163 deletions(-)
 create mode 100644 fetch-negotiator.c
 create mode 100644 fetch-negotiator.h
 create mode 100644 negotiator/default.c
 create mode 100644 negotiator/default.h