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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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r33089:9e0d222f default
r35994:48a3a928 default
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test-merge-default.t
175 lines | 3.9 KiB | text/troff | Tads3Lexer
/ tests / test-merge-default.t
$ hg init
$ echo a > a
$ hg commit -A -ma
adding a
$ echo b >> a
$ hg commit -mb
$ echo c >> a
$ hg commit -mc
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo d >> a
$ hg commit -md
created new head
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo e >> a
$ hg commit -me
created new head
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Should fail because not at a head:
$ hg merge
abort: working directory not at a head revision
(use 'hg update' or merge with an explicit revision)
[255]
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "f25cbe84d8b3: e"
2 other heads for branch "default"
Should fail because > 2 heads:
$ HGMERGE=internal:other; export HGMERGE
$ hg merge
abort: branch 'default' has 3 heads - please merge with an explicit rev
(run 'hg heads .' to see heads)
[255]
Should succeed:
$ hg merge 2
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg id -Tjson
[
{
"bookmarks": [],
"branch": "default",
"dirty": "+",
"id": "f25cbe84d8b3+2d95304fed5d+",
"node": "ffffffffffffffffffffffffffffffffffffffff",
"parents": [{"node": "f25cbe84d8b320e298e7703f18a25a3959518c23", "rev": 4}, {"node": "2d95304fed5d89bc9d70b2a0d02f0d567469c3ab", "rev": 2}],
"tags": ["tip"]
}
]
$ hg commit -mm1
Should succeed - 2 heads:
$ hg merge -P
changeset: 3:ea9ff125ff88
parent: 1:1846eede8b68
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: d
$ hg merge
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -mm2
$ hg id -r 1 -Tjson
[
{
"bookmarks": [],
"branch": "default",
"id": "1846eede8b68",
"node": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
"tags": []
}
]
Should fail because at tip:
$ hg merge
abort: nothing to merge
[255]
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Should fail because there is only one head:
$ hg merge
abort: nothing to merge
(use 'hg update' instead)
[255]
$ hg up 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo f >> a
$ hg branch foobranch
marked working directory as branch foobranch
(branches are permanent and global, did you want a bookmark?)
$ hg commit -mf
Should fail because merge with other branch:
$ hg merge
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]
Test for issue2043: ensure that 'merge -P' shows ancestors of 6 that
are not ancestors of 7, regardless of where their common ancestors are.
Merge preview not affected by common ancestor:
$ hg up -q 7
$ hg merge -q -P 6
2:2d95304fed5d
4:f25cbe84d8b3
5:a431fabd6039
6:e88e33f3bf62
Test experimental destination revset
$ hg log -r '_destmerge()'
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]
(on a branch with a two heads)
$ hg up 5
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo f >> a
$ hg commit -mf
created new head
$ hg log -r '_destmerge()'
changeset: 6:e88e33f3bf62
parent: 5:a431fabd6039
parent: 3:ea9ff125ff88
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m2
(from the other head)
$ hg log -r '_destmerge(e88e33f3bf62)'
changeset: 8:b613918999e2
tag: tip
parent: 5:a431fabd6039
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: f
(from unrelated branch)
$ hg log -r '_destmerge(foobranch)'
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]