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
$ hg init
$ cat << EOF > a
> Small Mathematical Series.
> One
> Two
> Three
> Four
> Five
> Hop we are done.
> EOF
$ hg add a
$ hg commit -m ancestor
$ cat << EOF > a
> Small Mathematical Series.
> 1
> 2
> 3
> 4
> 5
> Hop we are done.
> EOF
$ hg commit -m branch1
$ hg co 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cat << EOF > a
> Small Mathematical Series.
> 1
> 2
> 3
> 6
> 8
> Hop we are done.
> EOF
$ hg commit -m branch2
created new head
$ hg merge 1
merging a
warning: conflicts while merging a! (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 or 'hg merge --abort' to abandon
[1]
$ hg id
618808747361+c0c68e4fe667+ tip
$ echo "[commands]" >> $HGRCPATH
$ echo "status.verbose=true" >> $HGRCPATH
$ hg status
M a
? a.orig
# The repository is in an unfinished *merge* state.
# Unresolved merge conflicts:
#
# a
#
# To mark files as resolved: hg resolve --mark FILE
# To continue: hg commit
# To abort: hg update --clean . (warning: this will discard uncommitted changes)
$ cat a
Small Mathematical Series.
1
2
3
<<<<<<< working copy: 618808747361 - test: branch2
6
8
=======
4
5
>>>>>>> merge rev: c0c68e4fe667 - test: branch1
Hop we are done.
$ hg status --config commands.status.verbose=0
M a
? a.orig
Verify custom conflict markers
$ hg up -q --clean .
$ cat <<EOF >> .hg/hgrc
> [ui]
> mergemarkertemplate = '{author} {rev}'
> EOF
$ hg merge 1
merging a
warning: conflicts while merging a! (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 or 'hg merge --abort' to abandon
[1]
$ cat a
Small Mathematical Series.
1
2
3
<<<<<<< working copy: test 2
6
8
=======
4
5
>>>>>>> merge rev: test 1
Hop we are done.
Verify line splitting of custom conflict marker which causes multiple lines
$ hg up -q --clean .
$ cat >> .hg/hgrc <<EOF
> [ui]
> mergemarkertemplate={author} {rev}\nfoo\nbar\nbaz
> EOF
$ hg -q merge 1
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
[1]
$ cat a
Small Mathematical Series.
1
2
3
<<<<<<< working copy: test 2
6
8
=======
4
5
>>>>>>> merge rev: test 1
Hop we are done.
Verify line trimming of custom conflict marker using multi-byte characters
$ hg up -q --clean .
$ $PYTHON <<EOF
> fp = open('logfile', 'wb')
> fp.write(b'12345678901234567890123456789012345678901234567890' +
> b'1234567890') # there are 5 more columns for 80 columns
>
> # 2 x 4 = 8 columns, but 3 x 4 = 12 bytes
> fp.write(u'\u3042\u3044\u3046\u3048'.encode('utf-8'))
>
> fp.close()
> EOF
$ hg add logfile
$ hg --encoding utf-8 commit --logfile logfile
$ cat >> .hg/hgrc <<EOF
> [ui]
> mergemarkertemplate={desc|firstline}
> EOF
$ hg -q --encoding utf-8 merge 1
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
[1]
$ cat a
Small Mathematical Series.
1
2
3
<<<<<<< working copy: 1234567890123456789012345678901234567890123456789012345...
6
8
=======
4
5
>>>>>>> merge rev: branch1
Hop we are done.
Verify basic conflict markers
$ hg up -q --clean 2
$ printf "\n[ui]\nmergemarkers=basic\n" >> .hg/hgrc
$ hg merge 1
merging a
warning: conflicts while merging a! (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 or 'hg merge --abort' to abandon
[1]
$ cat a
Small Mathematical Series.
1
2
3
<<<<<<< working copy
6
8
=======
4
5
>>>>>>> merge rev
Hop we are done.
internal:merge3
$ hg up -q --clean .
$ hg merge 1 --tool internal:merge3
merging a
warning: conflicts while merging a! (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 or 'hg merge --abort' to abandon
[1]
$ cat a
Small Mathematical Series.
<<<<<<< working copy
1
2
3
6
8
||||||| base
One
Two
Three
Four
Five
=======
1
2
3
4
5
>>>>>>> merge rev
Hop we are done.
Add some unconflicting changes on each head, to make sure we really
are merging, unlike :local and :other
$ hg up -C
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "e0693e20f496: 123456789012345678901234567890123456789012345678901234567890????"
1 other heads for branch "default"
$ printf "\n\nEnd of file\n" >> a
$ hg ci -m "Add some stuff at the end"
$ hg up -r 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ printf "Start of file\n\n\n" > tmp
$ cat a >> tmp
$ mv tmp a
$ hg ci -m "Add some stuff at the beginning"
Now test :merge-other and :merge-local
$ hg merge
merging a
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
1 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ hg resolve --tool :merge-other a
merging a
(no more unresolved files)
$ cat a
Start of file
Small Mathematical Series.
1
2
3
6
8
Hop we are done.
End of file
$ hg up -C
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
updated to "18b51d585961: Add some stuff at the beginning"
1 other heads for branch "default"
$ hg merge --tool :merge-local
merging a
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat a
Start of file
Small Mathematical Series.
1
2
3
4
5
Hop we are done.
End of file