Now that servers expose a capability indicating they support
application/mercurial-0.2 and compression, clients can key off
this to say they support responses that are compressed with
various compression formats.
After this commit, the HTTP wire protocol client now sends an
"X-HgProto-<N>" request header indicating its support for
"application/mercurial-0.2" media type and various compression
formats.
This commit also implements support for handling
"application/mercurial-0.2" responses. It simply reads the header
compression engine identifier then routes the remainder of the
response to the appropriate decompressor.
There were some test changes, but only to logging. That points to
an obvious gap in our test coverage. This will be addressed in a
subsequent commit once server support is in place (it is hard to
test without server support).
Currently, exchange.getbundle() returns either a cg1unpacker or a
util.chunkbuffer (in the case of bundle2). This is kinda OK, as
both expose a .read() to consumers. However, localpeer.getbundle()
has code inferring what the response type is based on arguments and
converts the util.chunkbuffer returned in the bundle2 case to a
bundle2.unbundle20 instance. This is a sign that the API for
exchange.getbundle() is not ideal because it doesn't consistently
return an "unbundler" instance.
In addition, unbundlers mask the fact that there is an underlying
generator of changegroup data. In both cg1 and bundle2, this generator
is being fed into a util.chunkbuffer so it can be re-exposed as a
file object.
util.chunkbuffer is a nice abstraction. However, it should only be
used "at the edges." This is because keeping data as a generator is
more efficient than converting it to a chunkbuffer, especially if we
convert that chunkbuffer back to a generator (as is the case in some
code paths currently).
This patch refactors exchange.getbundle() into
exchange.getbundlechunks(). The new API returns an iterator of chunks
instead of a file-like object.
Callers of exchange.getbundle() have been updated to use the new API.
There is a minor change of behavior in test-getbundle.t. This is
because `hg debuggetbundle` isn't defining bundlecaps. As a result,
a cg1 data stream and unpacker is being produced. This is getting fed
into a new bundle20 instance via bundle2.writebundle(), which uses
a backchannel mechanism between changegroup generation to add the
"nbchanges" part parameter. I never liked this backchannel mechanism
and I plan to remove it someday. `hg bundle` still produces the
"nbchanges" part parameter, so there should be no user-visible
change of behavior. I consider this "regression" a bug in
`hg debuggetbundle`. And that bug is captured by an existing
"TODO" in the code to use bundle2 capabilities.
The bundle2 changegroup part has an advisory param saying how many
changesets are in the part. Before this patch, we were setting
this part when generating bundle2 parts via the wire protocol but
not when generating local bundle2 files.
A side effect of not setting the changeset count part is that progress
bars don't work when applying changesets. As the tests show, this
impacted clone bundles, shelve, backup bundles, `hg unbundle`, and
anything touching bundle2 files.
This patch adds a backdoor to allow us to pass state from
changegroup generation into the unbundler. We store the number
of changesets in the changegroup in this state and use it to
populate the aforementioned advisory part parameter when generating
the bundle2 bundle.
I concede that I'm not thrilled by how state is being passed in
changegroup.py (it feels a bit hacky). I would love to overhaul the
rather confusing set of functions in changegroup.py with something that
passes rich objects around instead of e.g. low-level generators.
However, given the code freeze for 3.9 is imminent, I'd rather not
undertake this endeavor right now. This feels like the easiest way
to get the parameter added to the changegroup part.
`hg debugbundle` is calling repr() on bundle2 part params, which are
now util.sortdict instances. Unfortunately, repr() doesn't appear
to be deterministic for util.sortdict. So, we implement one.
We include the type name because that's the common convention for
__repr__ implementations. Having the type name in `hg debugbundle`
is a bit ugly. But it's a debug command and I don't care enough to
fix it.
It is finally time to freeze the bundle2 format! To do so we:
- rename HG2Y to HG20,
- drop "b2x:" prefix from all part names,
- rename capability to "bundle2-exp" to "bundle2"
- rename the hook flag from 'bundle2-exp' to 'bundle2'
This diff adds support to writebundle to generate a bundle2 wrapper; upcoming
diffs will add an option to write a v2 changegroup part instead of v1 in these
bundles.
This drops the options to run arbitrary shell commands within
commits and the option to create a file that gets appended to
in every revision. It now supports to not write file data at
all, which is very fast for generating a pure 00changelog.i
(useful for discovery tests, for instance).
Timings for 1000 linear nodes:
* Old `hg debugbuilddag -o '+1000'` took 4.5 secs.
* New `hg debugbuilddag -o '+1000'` takes 2 secs.
* New `hg debugbuilddag '+1000'` takes 0.8 secs.
(The last one creates only 00changelog.i).
Send the command arguments in the HTTP headers. The command is still part
of the URL. If the server does not have the 'httpheader' capability, the
client will send the command arguments in the URL as it did previously.
Web servers typically allow more data to be placed within the headers than
in the URL, so this approach will:
- Avoid HTTP errors due to using a URL that is too large.
- Allow Mercurial to implement a more efficient wire protocol.
An alternate approach is to send the arguments as part of the request body.
This approach has been rejected because it requires the use of POST
requests, so it would break any existing configuration that relies on the
request type for authentication or caching.
Extensibility:
- The header size is provided by the server, which makes it possible to
introduce an hgrc setting for it.
- The client ignores the capability value after the first comma, which
allows more information to be included in the future.
getbundle(common, heads) -> bundle
Returns the changegroup for all ancestors of heads which are not ancestors of common. For both
sets, the heads are included in the set.
Intended to eventually supercede changegroupsubset and changegroup. Uses heads of common region
to exclude unwanted changesets instead of bases of desired region, which is more useful and
easier to implement.
Designed to be extensible with new optional arguments (which will have to be guarded by
corresponding capabilities).
