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pack-protocol: clarify LF-handling in PKT-LINE()

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The spec is very inconsistent about which PKT-LINE() parts
of the grammar include a LF. On top of that, the code is not
consistent, either (e.g., send-pack does not put newlines
into the ref-update commands it sends).

Let's make explicit the long-standing expectation that we
generally expect pkt-lines to end in a newline, but that
receivers should be lenient. This makes the spec consistent,
and matches what git already does (though it does not always
fulfill the SHOULD).

We do make an exception for the push-cert, where the
receiving code is currently a bit pickier. This is a
reasonable way to be, as the data needs to be byte-for-byte
compatible with what was signed. We _could_ make up some
rules about signing a canonicalized version including
newlines, but that would require a code change, and is out
of scope for this patch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2015-09-03 04:24:09 -04:00 committed by Junio C Hamano
parent 16ffa6443e
commit 1c9b659d98
2 changed files with 30 additions and 21 deletions
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46
Documentation/technical/pack-protocol.txt
View file

@ -14,6 +14,14 @@ data. The protocol functions to have a server tell a client what is
currently on the server, then for the two to negotiate the smallest amount
of data to send in order to fully update one or the other.
pkt-line Format
---------------
The descriptions below build on the pkt-line format described in
protocol-common.txt. When the grammar indicate `PKT-LINE(...)`, unless
otherwise noted the usual pkt-line LF rules apply: the sender SHOULD
include a LF, but the receiver MUST NOT complain if it is not present.
Transports
----------
There are three transports over which the packfile protocol is
@ -143,9 +151,6 @@ with the object name that each reference currently points to.
003fe92df48743b7bc7d26bcaabfddde0a1e20cae47c refs/tags/v1.0^{}
0000
Server SHOULD terminate each non-flush line using LF ("\n") terminator;
client MUST NOT complain if there is no terminator.
The returned response is a pkt-line stream describing each ref and
its current value. The stream MUST be sorted by name according to
the C locale ordering.
@ -165,15 +170,15 @@ MUST peel the ref if it's an annotated tag.
flush-pkt
no-refs = PKT-LINE(zero-id SP "capabilities^{}"
NUL capability-list LF)
NUL capability-list)
list-of-refs = first-ref *other-ref
first-ref = PKT-LINE(obj-id SP refname
NUL capability-list LF)
NUL capability-list)
other-ref = PKT-LINE(other-tip / other-peeled)
other-tip = obj-id SP refname LF
other-peeled = obj-id SP refname "^{}" LF
other-tip = obj-id SP refname
other-peeled = obj-id SP refname "^{}"
shallow = PKT-LINE("shallow" SP obj-id)
@ -216,8 +221,8 @@ out of what the server said it could do with the first 'want' line.
depth-request = PKT-LINE("deepen" SP depth)
first-want = PKT-LINE("want" SP obj-id SP capability-list LF)
additional-want = PKT-LINE("want" SP obj-id LF)
first-want = PKT-LINE("want" SP obj-id SP capability-list)
additional-want = PKT-LINE("want" SP obj-id)
depth = 1*DIGIT
----
@ -284,7 +289,7 @@ so that there is always a block of 32 "in-flight on the wire" at a time.
compute-end
have-list = *have-line
have-line = PKT-LINE("have" SP obj-id LF)
have-line = PKT-LINE("have" SP obj-id)
compute-end = flush-pkt / PKT-LINE("done")
----
@ -348,10 +353,10 @@ Then the server will start sending its packfile data.
----
server-response = *ack_multi ack / nak
ack_multi = PKT-LINE("ACK" SP obj-id ack_status LF)
ack_multi = PKT-LINE("ACK" SP obj-id ack_status)
ack_status = "continue" / "common" / "ready"
ack = PKT-LINE("ACK SP obj-id LF)
nak = PKT-LINE("NAK" LF)
ack = PKT-LINE("ACK" SP obj-id)
nak = PKT-LINE("NAK")
----
A simple clone may look like this (with no 'have' lines):
@ -467,10 +472,10 @@ references.
----
update-request = *shallow ( command-list | push-cert ) [packfile]
shallow = PKT-LINE("shallow" SP obj-id LF)
shallow = PKT-LINE("shallow" SP obj-id)
command-list = PKT-LINE(command NUL capability-list LF)
*PKT-LINE(command LF)
command-list = PKT-LINE(command NUL capability-list)
*PKT-LINE(command)
flush-pkt
command = create / delete / update
@ -521,7 +526,8 @@ Push Certificate
A push certificate begins with a set of header lines. After the
header and an empty line, the protocol commands follow, one per
line.
line. Note that the the trailing LF in push-cert PKT-LINEs is _not_
optional; it must be present.
Currently, the following header fields are defined:
@ -560,12 +566,12 @@ update was successful, or 'ng [refname] [error]' if the update was not.
1*(command-status)
flush-pkt
unpack-status = PKT-LINE("unpack" SP unpack-result LF)
unpack-status = PKT-LINE("unpack" SP unpack-result)
unpack-result = "ok" / error-msg
command-status = command-ok / command-fail
command-ok = PKT-LINE("ok" SP refname LF)
command-fail = PKT-LINE("ng" SP refname SP error-msg LF)
command-ok = PKT-LINE("ok" SP refname)
command-fail = PKT-LINE("ng" SP refname SP error-msg)
error-msg = 1*(OCTECT) ; where not "ok"
----

5
Documentation/technical/protocol-common.txt
View file

@ -62,7 +62,10 @@ A pkt-line MAY contain binary data, so implementors MUST ensure
pkt-line parsing/formatting routines are 8-bit clean.
A non-binary line SHOULD BE terminated by an LF, which if present
MUST be included in the total length.
MUST be included in the total length. Receivers MUST treat pkt-lines
with non-binary data the same whether or not they contain the trailing
LF (stripping the LF if present, and not complaining when it is
missing).
The maximum length of a pkt-line's data component is 65520 bytes.
Implementations MUST NOT send pkt-line whose length exceeds 65524