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sshpeer: initial definition and implementation of new SSH protocol...
sshpeer: initial definition and implementation of new SSH protocol The existing SSH protocol has several design flaws. Future commits will elaborate on these flaws as new features are introduced to combat these flaws. For now, hopefully you can take me for my word that a ground up rewrite of the SSH protocol is needed. This commit lays the foundation for a new SSH protocol by defining a mechanism to upgrade the SSH transport channel away from the default (version 1) protocol to something modern (which we'll call "version 2" for now). This upgrade process is detailed in the internals documentation for the wire protocol. The gist of it is the client sends a request line preceding the "hello" command/line which basically says "I'm requesting an upgrade: here's what I support." If the server recognizes that line, it processes the upgrade request and the transport channel is switched to use the new version of the protocol. If not, it sends an empty response, which is how all Mercurial SSH servers from the beginning of time reacted to unknown commands. The upgrade request is effectively ignored and the client continues to use the existing version of the protocol as if nothing happened. The new version of the SSH protocol is completely identical to version 1 aside from the upgrade dance and the bytes that follow. The immediate bytes that follow the protocol switch are defined to be a length framed "capabilities: " line containing the remote's advertised capabilities. In reality, this looks very similar to what the "hello" response would look like. But it will evolve quickly. The methodology by which the protocol will evolve is important. I'm not going to introduce the new protocol all at once. That would likely lead to endless bike shedding and forward progress would stall. Instead, I intend to tricle out new features and diversions from the existing protocol in small, incremental changes. To support the gradual evolution of the protocol, the on-the-wire advertised protocol name contains an "exp" to denote "experimental" and a 4 digit field to capture the sub-version of the protocol. Whenever we make a BC change to the wire protocol, we can increment this version and lock out all older clients because it will appear as a completely different protocol version. This means we can incur as many breaking changes as we want. We don't have to commit to supporting any one feature or idea for a long period of time. We can even evolve the handshake mechanism, because that is defined as being an implementation detail of the negotiated protocol version! Hopefully this lowers the barrier to accepting changes to the protocol and for experimenting with "radical" ideas during its development. In core, sshpeer received most of the attention. We haven't even implemented the server bits for the new protocol in core yet. Instead, we add very primitive support to our test server, mainly just to exercise the added code paths in sshpeer. Differential Revision: https://phab.mercurial-scm.org/D2061 # no-check-commit because of required foo_bar naming

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test-histedit-non-commute-abort.t
165 lines | 4.5 KiB | text/troff | Tads3Lexer
/ tests / test-histedit-non-commute-abort.t
$ . "$TESTDIR/histedit-helpers.sh"
$ cat >> $HGRCPATH <<EOF
> [extensions]
> histedit=
> EOF
$ initrepo ()
> {
> hg init r
> cd r
> for x in a b c d e f ; do
> echo $x > $x
> hg add $x
> hg ci -m $x
> done
> echo a >> e
> hg ci -m 'does not commute with e'
> cd ..
> }
$ initrepo
$ cd r
log before edit
$ hg log --graph
@ changeset: 6:bfa474341cc9
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: does not commute with e
|
o changeset: 5:652413bf663e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: f
|
o changeset: 4:e860deea161a
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: e
|
o changeset: 3:055a42cdd887
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: d
|
o changeset: 2:177f92b77385
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: c
|
o changeset: 1:d2ae7f538514
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: b
|
o changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
edit the history
$ hg histedit 177f92b77385 --commands - 2>&1 <<EOF | fixbundle
> pick 177f92b77385 c
> pick 055a42cdd887 d
> pick bfa474341cc9 does not commute with e
> pick e860deea161a e
> pick 652413bf663e f
> EOF
merging e
warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
Fix up the change (pick e860deea161a)
(hg histedit --continue to resume)
insert unsupported advisory merge record
$ hg --config extensions.fakemergerecord=$TESTDIR/fakemergerecord.py fakemergerecord -x
$ hg debugmergestate
* version 2 records
local: 8f7551c7e4a2f2efe0bc8c741baf7f227d65d758
other: e860deea161a2f77de56603b340ebbb4536308ae
labels:
local: local
other: histedit
unrecognized entry: x advisory record
file extras: e (ancestorlinknode = 0000000000000000000000000000000000000000)
file: e (record type "F", state "u", hash 58e6b3a414a1e090dfc6029add0f3555ccba127f)
local path: e (flags "")
ancestor path: e (node null)
other path: e (node 6b67ccefd5ce6de77e7ead4f5292843a0255329f)
$ hg resolve -l
U e
insert unsupported mandatory merge record
$ hg --config extensions.fakemergerecord=$TESTDIR/fakemergerecord.py fakemergerecord -X
$ hg debugmergestate
* version 2 records
local: 8f7551c7e4a2f2efe0bc8c741baf7f227d65d758
other: e860deea161a2f77de56603b340ebbb4536308ae
labels:
local: local
other: histedit
file extras: e (ancestorlinknode = 0000000000000000000000000000000000000000)
file: e (record type "F", state "u", hash 58e6b3a414a1e090dfc6029add0f3555ccba127f)
local path: e (flags "")
ancestor path: e (node null)
other path: e (node 6b67ccefd5ce6de77e7ead4f5292843a0255329f)
unrecognized entry: X mandatory record
$ hg resolve -l
abort: unsupported merge state records: X
(see https://mercurial-scm.org/wiki/MergeStateRecords for more information)
[255]
$ hg resolve -ma
abort: unsupported merge state records: X
(see https://mercurial-scm.org/wiki/MergeStateRecords for more information)
[255]
abort the edit (should clear out merge state)
$ hg histedit --abort 2>&1 | fixbundle
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg debugmergestate
no merge state found
log after abort
$ hg resolve -l
$ hg log --graph
@ changeset: 6:bfa474341cc9
| tag: tip
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: does not commute with e
|
o changeset: 5:652413bf663e
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: f
|
o changeset: 4:e860deea161a
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: e
|
o changeset: 3:055a42cdd887
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: d
|
o changeset: 2:177f92b77385
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: c
|
o changeset: 1:d2ae7f538514
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: b
|
o changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
$ cd ..