Adds a new discovery method based on repeatedly sampling the still
undecided subset of the local node graph to determine the set of nodes
common to both the client and the server.
For small differences between client and server, it uses about the same
or slightly fewer roundtrips than the old tree-based discovery. For
larger differences, it typically reduces the number of roundtrips
drastically (from 150 to 4, for instance).
The old discovery code now lives in treediscovery.py, the new code is
in setdiscovery.py.
Still missing is a hook for extensions to contribute nodes to the
initial sample. For instance, Augie's remotebranches could contribute
the last known state of the server's heads.
Credits for the actual sampler and computing common heads instead of
bases go to Benoit Boissinot.
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).
Add missing calls to close() to many places where files are
opened. Relying on reference counting to catch them soon-ish is not
portable and fails in environments with a proper GC, such as PyPy.
Now that the nodemap is lazily created, we use linear scanning back
from tip for typical node to rev mapping. Given that nodemap creation
is O(n log n) and revisions searched for are usually very close to
tip, this is often a significant performance win for a small number of
searches.
When we do end up building a nodemap for bulk lookups, the scanning
function is replaced with a hash lookup.
We were not returning the correct result if nullrev was in revs, as we
are checking parent(currentrev) != nullrev before yielding currentrev
test-convert-hg-startrev was wrong: if we start converting from rev -1 and
onwards, all the descendants of -1 (full repo) should be converted.
When parentdelta is enabled, we choose the delta that has the minimum
distance to its base. Otherwise, base may be sufficiently far away to
require a full version, resulting in greatly reduced compression.
While reading changegroup if a node with missing parents is encountered,
we add a punched entry in the index with null parents for the missing
parent node.
