revlog: update data file record before index rename When migrating from inline to non-inline data storage, the data file is recorded initially as zero sized so that it is removed on failure. But the record has to be updated before the index is renamed, otherwise data is lost on rollback. Differential Revision: https://phab.mercurial-scm.org/D10725

revlog: fix index computation during inline->non-inline transition The computation in 63edc384d3b7 failed to factor in the index entries themselve as revlog.start() doesn't count them. Found by Valtenin Gatienbaron with a more precise test case from me. Differential Revision: https://phab.mercurial-scm.org/D10724

dirstate-v2: Change the on-disk format to be tree-shaped Nodes are stored not only for tracked files but also for their ancestor directories. A node has "pointers" (byte count from the start of the file) to its direct child nodes. Everything can be accessed with zero copy. Differential Revision: https://phab.mercurial-scm.org/D10722

dirstate-tree: Extract into a method sorting children of a given node A later changset will use this in another place. This is an associated function (that Python would call static method) instead of a free function so it doesn’t need to be imported separately. It’s on `Node` rather than `ChildNodes` because the latter is a type alias to an external type (`HashMap`) so that would require an extension trait which needs to be imported separately. Differential Revision: https://phab.mercurial-scm.org/D10721

dirstate-v2: Add a variant of some tests, that uses the new format With this, the new format receives some testing every time someone runs tests with Rust extensions enabled, including on CI. Differential Revision: https://phab.mercurial-scm.org/D10720

dirstate-v2: Change the on-disk format when the requirement is enabled For now, the format is the same except with an additional marker at the start. This marker is redundant: for existing repositories it is `.hg/requires` that determines which format to use. For new repositories, it is the new `format.exp-dirstate-v2` config. There is no upgrade or downgrade so far. Most of the changes are about plumbing a boolean through layers of APIs to indicate which format should be used. Differential Revision: https://phab.mercurial-scm.org/D10719

dirstate-v2: Update the expected output of some tests for new requirement Fix most test failures (except in test-narrow-debugrebuilddirstate.t and test-upgrade-repo.t) caused by the new entry in config or in .hg/requires when running `run-tests.py --extra-config-opt format.exp-dirstate-v2=1` There is no CI so far for this configuration. Differential Revision: https://phab.mercurial-scm.org/D10718

tests: More cleanly separate expected hexdump output There are more lines that differ than are in common, and dirstate-v2 will complicate that further. Differential Revision: https://phab.mercurial-scm.org/D10717