This is an overview of the 5.7 release.
There is a new config section for templates used by hg commands. It called [command-templates]. Some existing config options have been deprecated in favor of config options in the new section. These are:
ui.logtemplate to command-templates.log,
ui.graphnodetemplate to command-templates.graphnode,
ui.mergemarkertemplate to command-templates.mergemarker,
ui.pre-merge-tool-output-template to command-templates.pre-merge-tool-output.
There is a new set of config options for the template used for the one-line commit summary displayed by various commands, such as hg rebase. The main one is command-templates.oneline-summary. That can be overridden per command with command-templates.oneline-summary.<command>, where <command> can be e.g. rebase. As part of this effort, the default format from hg rebase was reorganized a bit.
hg purge is now a core command using --confirm by default.
hg diff and hg extdiff now support --from <rev> and --to <rev> arguments as clearer alternatives to -r <revs>. -r <revs> has been deprecated.
- The memory footprint per changeset during pull/unbundle operations has been further reduced.
There is a new internal merge tool called internal:mergediff (can be set as the value for the merge config in the [ui] section). It resolves merges the same was as internal:merge and internal:merge3, but it shows conflicts differently. Instead of showing 2 or 3 snapshots of the conflicting pieces of code, it shows one snapshot and a diff. This may be useful when at least one side of the conflict is similar to the base. The new marker style is also supported by "premerge" as merge-tools.<tool>.premerge=keep-mergediff.
External hooks are now called with HGPLAIN=1 preset. This has the side effect of ignoring aliases, templates, revsetaliases, and a few other config options in any hg command spawned by the hook. The previous behavior can be restored by setting HGPLAINEXCEPT appropriately in the parent process.
See hg help environment for the list of items, and how to set it.
The branchmap cache is updated more intelligently and can be significantly faster for repositories with many branches and changesets.
The rev-branch-cache is now updated incrementally whenever changesets are added.
New Experimental Features
experimental.single-head-per-branch:public-changes-only can be used restrict the single head check to public revision. This is useful for overlay repository that have both a publishing and non-publishing view of the same storage.
Backwards Compatibility Changes
--force-lock and --force-wlock options on hg debuglock command are renamed to --force-free-lock and --force-free-wlock respectively.
Internal API Changes
changelog.branchinfo is deprecated and will be removed after 5.8. It is superseded by changelogrevision.branchinfo.