exchangev2: fetch and apply phases data
Now that the server supports emitting phases data, we can request it
and apply it on the client.
Because we may receive phases-only updates from the server, we no
longer conditionally perform the "changesetdata" command depending
on whether there are revisions to fetch. In the previous wire
protocol, this case would result in us falling back to performing
"listkeys" commands to look up phases, bookmarks, etc data. But
since "changesetdata" is smart enough to handle metadata only
fetches, we can keep things consistent.
It's worth noting that because of the unified approach to changeset
data retrieval, phase handling code in wire proto v2 exchange is
drastically simpler. Contrast with all the code in exchange.py
dealing with all the variations for obtaining phases data.
Differential Revision: https://phab.mercurial-scm.org/D4484
$ hg init repo
$ cd repo
$ touch a.html b.html c.py d.py
$ cat > frontend.sparse << EOF
> [include]
> *.html
> EOF
$ hg -q commit -A -m initial
$ echo 1 > a.html
$ echo 1 > c.py
$ hg commit -m 'commit 1'
Enable sparse profile
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
$ hg debugsparse --config extensions.sparse= --enable-profile frontend.sparse
$ ls
a.html
b.html
Requirement for sparse added when sparse is enabled
$ cat .hg/requires
dotencode
exp-sparse
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
Client without sparse enabled reacts properly
$ hg files
abort: repository is using sparse feature but sparse is not enabled; enable the "sparse" extensions to access!
[255]
Requirement for sparse is removed when sparse is disabled
$ hg debugsparse --reset --config extensions.sparse=
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
testonly-simplestore (reposimplestore !)
And client without sparse can access
$ hg files
a.html
b.html
c.py
d.py
frontend.sparse