Re: [PATCH] http-protocol.txt: add missing flush to example
From: Jeff King <hidden>
Date: 2021-11-18 16:38:57
On Thu, Nov 18, 2021 at 11:16:43AM +0000, TimTIM via GitGitGadget wrote:
From: TimTim Wong <redacted>
Signed-off-by: Timothy Wong <redacted>
---
Fix example in documentation
wants must be flushed with 0000 before havesThis explanation would probably make more sense in the commit message. I think this is only true for the v0 protocol. In the v2 protocol, we take all of the wants/haves as a single sequence. That may be OK for our purposes here, though. While the v2 docs do refer to http-protocol.txt, it is only for the "Initial Client Request" section. The actual v2 fetch primitive is defined separately in protocol-v2.txt.
quoted hunk ↗ jump to hunk
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt index cc5126cfeda..facb315a993 100644 --- a/Documentation/technical/http-protocol.txt +++ b/Documentation/technical/http-protocol.txt@@ -314,8 +314,9 @@ Clients MUST first perform ref discovery with C: Content-Type: application/x-git-upload-pack-request C: C: 0032want 0a53e9ddeaddad63ad106860237bbf53411d11a7\n - C: 0032have 441b40d833fdfa93eb2908e52742248faf0ee993\n C: 0000 + C: 0032have 441b40d833fdfa93eb2908e52742248faf0ee993\n + C: done
OK, so the "have" lines moves after the flush, which makes sense. There's no longer a trailing flush, though. Instead, we put in a "done" command. This is OK, and what we'd often send in practice, but it is optional (due to "no-done"). I wonder if it is worth keeping things simpler. I dunno. (BTW, if you run with GIT_TRACE_PACKET here, it's a bit misleading. We _do_ send a flush after the "done", but it's the flush to tell remote-curl that it should send the stateless-rpc packet; it doesn't actually go over the wire with the HTTP request).
quoted hunk ↗ jump to hunk
@@ -337,9 +338,9 @@ server advertises capability `allow-tip-sha1-in-want` or `allow-reachable-sha1-in-want`. compute_request = want_list + "0000" have_list - request_end - request_end = "0000" / "done" + "done"
OK, so here we put the flush after want_list, which is good. But this
loses the optionality of "done". I think it's valid to just send the
flush, but this BNF no longer reflects that. Or if I'm wrong, I think
this needs to be discussed in the commit message.
I wondered if the non-http protocol had a similar problem, but it treats
the "want" and "have" phases more independently. E.g., we get:
upload-request = want-list
*shallow-line
*1depth-request
[filter-request]
flush-pkt
and then later:
upload-haves = have-list
compute-end
compute-end = flush-pkt / PKT-LINE("done")
which is OK.
-Peff