view relnotes/5.2 @ 44333:50ad851efd9b

nodemap: introduce append-only incremental update of the persistent data

Rewriting the full nodemap for each transaction has a cost we would like to
avoid. We introduce a new way to write persistent nodemap data by adding new
information at the end for file. Any new and updated block as added at the end
of the file. The last block is the new root node.

With this method, some of the block already on disk get "dereferenced" and
become dead data. In later changesets, We'll start tracking the amount of dead
data to eventually re-generate a full nodemap.

Differential Revision: https://phab.mercurial-scm.org/D7886

== New Features ==

 * The amend extension supports the `--currentuser` argument.

 * The amend extension supports the `--close-branch` argument.

 * The amend extension supports the `--secret` argument.

 * The uncommit extension supports the `rewrite.update-timestamp` config option.

== New Experimental Features ==


== Bug Fixes  ==


== Backwards Compatibility Changes ==

 * A shell that supports `$(command)`` syntax for command substitution is now
   required for running the test suite. The test runner normally uses
   `sh`, so if that is a shell that doesn't support `$(command)` syntax,
   you can override it by setting `$HGTEST_SHELL` or by passing it to
   `run-tests.py --shell <shell>`.

 * The (experimental) narrow extension's wire protocol changed. If
   you're using it, you'll need to make sure to upgrade server and
   client at the same time.

== Internal API Changes ==