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 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 ..