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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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r34943:2a774cae stable
r35994:48a3a928 default
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test-update-names.t
89 lines | 2.2 KiB | text/troff | Tads3Lexer
Test update logic when there are renames or weird same-name cases between dirs
and files
Update with local changes across a file rename
$ hg init r1 && cd r1
$ echo a > a
$ hg add a
$ hg ci -m a
$ hg mv a b
$ hg ci -m rename
$ echo b > b
$ hg ci -m change
$ hg up -q 0
$ echo c > a
$ hg up
merging a and b to b
warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
Test update when local untracked directory exists with the same name as a
tracked file in a commit we are updating to
$ hg init r2 && cd r2
$ echo root > root && hg ci -Am root # rev 0
adding root
$ echo text > name && hg ci -Am "name is a file" # rev 1
adding name
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkdir name
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test update when local untracked directory exists with some files in it and has
the same name a tracked file in a commit we are updating to. In future this
should be updated to give an friendlier error message, but now we should just
make sure that this does not erase untracked data
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkdir name
$ echo text > name/file
$ hg st
? name/file
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
#if symlink
Test update when two commits have symlinks that point to different folders
$ hg init r3 && cd r3
$ echo root > root && hg ci -Am root
adding root
$ mkdir folder1 && mkdir folder2
$ ln -s folder1 folder
$ hg ci -Am "symlink to folder1"
adding folder
$ rm folder
$ ln -s folder2 folder
$ hg ci -Am "symlink to folder2"
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
#endif
#if rmcwd
Test that warning is printed if cwd is deleted during update
$ hg init r4 && cd r4
$ mkdir dir
$ cd dir
$ echo a > a
$ echo b > b
$ hg add a b
$ hg ci -m "file and dir"
$ hg up -q null
current directory was removed
(consider changing to repo root: $TESTTMP/r1/r4)
#endif