wireproto: define and implement HTTP handshake to upgrade protocol
When clients connect to repositories over HTTP, they issue a request
to the well-known URL "?cmd=capabilities" to fetch the repository
capabilities. This is the handshake portion of the HTTP protocol.
This commit defines a mechanism to use that HTTP request to return
information about modern server features.
If a client sends an X-HgUpgrade-* header containing a list of
client-supported API names, the server responds with a response
containing information about available services. This includes
the normal capabilities string. So if the server doesn't support
any newer services, the client can easily fall back.
By advertising supported services from clients, server operators
can see and log what client support exists in the wild. This will
also help with debugging.
The response contains the base path to API services. We know there
are potential issues with the <repo>/api/ URL space conflicting with
hgwebdir and subrepos. By making the API URL dynamic from the
perspective of the client, the URL for APIs is not subject to backwards
compatibility concerns - at least as long as a ?cmd=capabilities request
is made.
We've also defined the ``cbor`` client capability for the X-HgProto-*
header. This MUST be sent in order to get the modern response from
"?cmd=capabilities". During implementation, I initially always sent
an application/mercurial-cbor response. However, the handshake
mechanism will be more future compatible if the client is in charge
of which formats to request. We already perform content negotiation
from X-HgProto-*, so keying off this for the capabilities response
feels appropriate.
In addition, I initially used application/cbor. However, it is
conceivable that a non-Mercurial server could serve application/cbor.
To rule out this possibility, I've invented a new media type that
is Mercurial specific and can't be confused for generic CBOR.
Differential Revision: https://phab.mercurial-scm.org/D3242
$ cat >> $HGRCPATH <<EOF
> [extensions]
> convert=
> [convert]
> hg.saverev=False
> EOF
$ hg init orig
$ cd orig
$ echo foo > foo
$ echo bar > bar
$ hg ci -qAm 'add foo bar' -d '0 0'
$ echo >> foo
$ hg ci -m 'change foo' -d '1 0'
$ hg up -qC 0
$ hg copy --after --force foo bar
$ hg copy foo baz
$ hg ci -m 'make bar and baz copies of foo' -d '2 0'
created new head
Test that template can print all file copies (issue4362)
$ hg log -r . --template "{file_copies % ' File: {file_copy}\n'}"
File: bar (foo)
File: baz (foo)
$ hg bookmark premerge1
$ hg merge -r 1
merging baz and foo to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge local copy' -d '3 0'
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark premerge1)
$ hg bookmark premerge2
$ hg merge 2
merging foo and baz to baz
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'merge remote copy' -d '4 0'
created new head
Make and delete some tags
$ hg tag that
$ hg tag --remove that
$ hg tag this
#if execbit
$ chmod +x baz
#else
$ echo some other change to make sure we get a rev 5 > baz
#endif
$ hg ci -m 'mark baz executable' -d '5 0'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
initializing destination new repository
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 88586c4e9f02
2 Removed tag that
1 Added tag this for changeset c56a7f387039
0 mark baz executable
updating bookmarks
$ cd new
$ hg out ../orig
comparing with ../orig
searching for changes
no changes found
[1]
#if execbit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:91d107c423ba
#else
Different hash because no x bit
$ hg bookmarks
premerge1 3:973ef48a98a4
premerge2 8:3537b15eaaca
#endif
Test that redoing a convert results in an identical graph
$ cd ../
$ rm new/.hg/shamap
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
8 add foo bar
7 change foo
6 make bar and baz copies of foo
5 merge local copy
4 merge remote copy
3 Added tag that for changeset 88586c4e9f02
2 Removed tag that
1 Added tag this for changeset c56a7f387039
0 mark baz executable
updating bookmarks
$ hg -R new log -G -T '{rev} {desc}'
o 8 mark baz executable
|
o 7 Added tag this for changeset c56a7f387039
|
o 6 Removed tag that
|
o 5 Added tag that for changeset 88586c4e9f02
|
o 4 merge remote copy
|\
+---o 3 merge local copy
| |/
| o 2 make bar and baz copies of foo
| |
o | 1 change foo
|/
o 0 add foo bar
check shamap LF and CRLF handling
$ cat > rewrite.py <<EOF
> import sys
> # Interlace LF and CRLF
> lines = [(l.rstrip() + ((i % 2) and b'\n' or b'\r\n'))
> for i, l in enumerate(open(sys.argv[1], 'rb'))]
> open(sys.argv[1], 'wb').write(b''.join(lines))
> EOF
$ $PYTHON rewrite.py new/.hg/shamap
$ cd orig
$ hg up -qC 1
$ echo foo >> foo
$ hg ci -qm 'change foo again'
$ hg up -qC 2
$ echo foo >> foo
$ hg ci -qm 'change foo again again'
$ cd ..
$ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
scanning source...
sorting...
converting...
1 change foo again again
0 change foo again
updating bookmarks
init broken repository
$ hg init broken
$ cd broken
$ echo a >> a
$ echo b >> b
$ hg ci -qAm init
$ echo a >> a
$ echo b >> b
$ hg copy b c
$ hg ci -qAm changeall
$ hg up -qC 0
$ echo bc >> b
$ hg ci -m changebagain
created new head
$ HGMERGE=internal:local hg -q merge
$ hg ci -m merge
$ hg mv b d
$ hg ci -m moveb
break it
#if reporevlogstore
$ rm .hg/store/data/b.*
#endif
#if reposimplestore
$ rm .hg/store/data/b/*
#endif
$ cd ..
$ hg --config convert.hg.ignoreerrors=True convert broken fixed
initializing destination fixed repository
scanning source...
sorting...
converting...
4 init
ignoring: data/b.i@1e88685f5dde: no match found (reporevlogstore !)
ignoring: data/b/index@1e88685f5dde: no node (reposimplestore !)
3 changeall
2 changebagain
1 merge
0 moveb
$ hg -R fixed verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 5 changesets, 5 total revisions
manifest -r 0
$ hg -R fixed manifest -r 0
a
manifest -r tip
$ hg -R fixed manifest -r tip
a
c
d