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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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r34706:23ed47a8 default
r35994:48a3a928 default
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test-pull-update.t
240 lines | 5.9 KiB | text/troff | Tads3Lexer
$ hg init t
$ cd t
$ echo 1 > foo
$ hg ci -Am m
adding foo
$ cd ..
$ hg clone t tt
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd tt
$ echo 1.1 > foo
$ hg ci -Am m
$ cd ../t
$ echo 1.2 > foo
$ hg ci -Am m
Should respect config to disable dirty update
$ hg co -qC 0
$ echo 2 > foo
$ hg --config commands.update.check=abort pull -u ../tt
pulling from ../tt
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 107cefe13e42
abort: uncommitted changes
[255]
$ hg --config extensions.strip= strip --no-backup tip
$ hg co -qC tip
Should not update to the other topological branch:
$ hg pull -u ../tt
pulling from ../tt
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 107cefe13e42
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "800c91d5bfc1: m"
1 other heads for branch "default"
$ cd ../tt
Should not update to the other branch:
$ hg pull -u ../t
pulling from ../t
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 800c91d5bfc1
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "107cefe13e42: m"
1 other heads for branch "default"
$ HGMERGE=true hg merge
merging foo
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -mm
$ cd ../t
Should work:
$ hg pull -u ../tt
pulling from ../tt
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (-1 heads)
new changesets 483b76ad4309
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Similarity between "hg update" and "hg pull -u" in handling bookmark
====================================================================
Test that updating activates the bookmark, which matches with the
explicit destination of the update.
$ echo 4 >> foo
$ hg commit -m "#4"
$ hg bookmark active-after-pull
$ cd ../tt
(1) activating by --rev BOOKMARK
$ hg bookmark -f active-before-pull
$ hg bookmarks
* active-before-pull 3:483b76ad4309
$ hg pull -u -r active-after-pull
pulling from $TESTTMP/t
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
adding remote bookmark active-after-pull
new changesets f815b3da6163
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark active-after-pull)
$ hg parents -q
4:f815b3da6163
$ hg bookmarks
* active-after-pull 4:f815b3da6163
active-before-pull 3:483b76ad4309
(discard pulled changes)
$ hg update -q 483b76ad4309
$ hg rollback -q
(2) activating by URL#BOOKMARK
$ hg bookmark -f active-before-pull
$ hg bookmarks
* active-before-pull 3:483b76ad4309
$ hg pull -u $TESTTMP/t#active-after-pull
pulling from $TESTTMP/t
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
adding remote bookmark active-after-pull
new changesets f815b3da6163
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark active-after-pull)
$ hg parents -q
4:f815b3da6163
$ hg bookmarks
* active-after-pull 4:f815b3da6163
active-before-pull 3:483b76ad4309
(discard pulled changes)
$ hg update -q 483b76ad4309
$ hg rollback -q
Test that updating deactivates current active bookmark, if the
destination of the update is explicitly specified, and it doesn't
match with the name of any existing bookmarks.
$ cd ../t
$ hg bookmark -d active-after-pull
$ hg branch bar -q
$ hg commit -m "#5 (bar #1)"
$ cd ../tt
(1) deactivating by --rev REV
$ hg bookmark -f active-before-pull
$ hg bookmarks
* active-before-pull 3:483b76ad4309
$ hg pull -u -r b5e4babfaaa7
pulling from $TESTTMP/t
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 1 changes to 1 files
new changesets f815b3da6163:b5e4babfaaa7
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(leaving bookmark active-before-pull)
$ hg parents -q
5:b5e4babfaaa7
$ hg bookmarks
active-before-pull 3:483b76ad4309
(discard pulled changes)
$ hg update -q 483b76ad4309
$ hg rollback -q
(2) deactivating by --branch BRANCH
$ hg bookmark -f active-before-pull
$ hg bookmarks
* active-before-pull 3:483b76ad4309
$ hg pull -u -b bar
pulling from $TESTTMP/t
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 1 changes to 1 files
new changesets f815b3da6163:b5e4babfaaa7
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(leaving bookmark active-before-pull)
$ hg parents -q
5:b5e4babfaaa7
$ hg bookmarks
active-before-pull 3:483b76ad4309
(discard pulled changes)
$ hg update -q 483b76ad4309
$ hg rollback -q
(3) deactivating by URL#ANOTHER-BRANCH
$ hg bookmark -f active-before-pull
$ hg bookmarks
* active-before-pull 3:483b76ad4309
$ hg pull -u $TESTTMP/t#bar
pulling from $TESTTMP/t
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 1 changes to 1 files
new changesets f815b3da6163:b5e4babfaaa7
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(leaving bookmark active-before-pull)
$ hg parents -q
5:b5e4babfaaa7
$ hg bookmarks
active-before-pull 3:483b76ad4309
$ cd ..