Merge

tests: reduce spurious failures when run with generaldelta Quite a few tests fail in noisy but meaningless ways when the test suite is run with generaldelta enabled: ./run-tests.py --extra-config-opt=format.generaldelta=1 This reduces the amount of noise introduced by the debugindex command, the main source of differences. In my environment, when testing with generaldelta enabled, this change reduces the number of completely failing tests from 21 to 8.

histedit: add extension docstring from external README Made a couple of tweaks to try and fit better with the hg docstring style and fix up some ReST errors in the README.

histedit: don't crash if the result of fixing up a fold is empty

histedit: replace hexshort lambda with node.short

revlog: make compress a method This allows an extension to optionally use a new compression type based on the options applied by the repo to the revlog's opener. (decompress doesn't need the same treatment, as it can be replaced using extensions.wrapfunction, and can figure out which compression algorithm is in use based on the first byte of the compressed payload.)

largefiles: batch statlfile requests when pushing a largefiles repo (issue3386) This implements a part of issue 3386. It batches the request for the status of all largefiles in the revisions that are about to be pushed into a single request, instead of doing N separate requests. In a real world test case, this change was verified to save 1,116 round-trips to the server. It only requires a client-side change; it is backwards-compatible with an older version of the server.

obsolete: write obsolete marker inside a transaction Marker are now written as soon as possible but within a transaction. Using a transaction ensure a proper behavior on error and rollback compatibility. Flush logic are not necessary anymore and are dropped from lock release. With this changeset, the obsstore is open, written and closed for every single added marker. This is expected to be highly inefficient and batched write should be implemented "quickly". Another issue is that every flush of the file will invalidate the obsstore filecache and trigger a full re instantiation of the repo.obsstore attribute (including, reading and parsing entry). This is also expected to be highly inefficient and proper filecache operation should be implemented "quickly" too. A side benefit of the filecache issue is that repo.obsstore object is properly invalidated on transaction abortion.

obsolete: append new markers to obsstore file instead of rewriting everything This is the second step toward incremental writing of marker inside a transaction. The obsstore file is now handled append only. Header writing have been extracted from _writemarkers. Because the _writemarkers method have been dropped, the push code directly reuse the serialised content of local repo `listkeys`. This is not very pretty, but this part of the protocol still need major improvement anyway.

obsolete: move obsolete markers read/write logic to obsstore object This is the first step toward incremental writing of obsolete marker within a transaction. For this purpose, obsstore is now given its repo sopener. This make it able to handles read and write to the obsstore file itself. Most IO logic is removed from localrepo and handled by obsstore object directly.