relnotes/5.1

ui: refactor `readconfig()` into a form that can consume resources

The old form can't completely go away, because files outside of packages still
need to be read.  The name passed in here is a tuple of `package name, resource`
as needed by the resource API.

I like the idea of stating the config file is embedded in the executable by
listing is as `exe!package.resource`.  This would be consistent with how
`debuginstall` points to the executable for the python executable, lib, and
installed modules.  While in practice the filesystem path is available from the
backing ResourceReader when the resource is opened, it is a relative path on py2
and absolute on py3.  Further, while this would show in the `hg config` output
for each option if set as such here, it doesn't show in the `reading from...`
line when `--debug` is used.  The file isn't actually open where that prints, so
there's no way I see to get that info there.  So I opted for the simple prefix
to distinguish resources from files.

Differential Revision: https://phab.mercurial-scm.org/D7775

== New Features ==

 * New config `commands.commit.post-status` shows status after successful
 commit.

 * `hg root` now has templating support, including support for showing
   where a repo share's source is. See `hg help -v root` for details.

 * New `--force-close-branch` flag for `hg commit` to forcibly close
   branch from a non-head changeset.

 * The curses-based interface for commands like `hg commit -i` now supports
   a range-select mechanism. Select the first line using space like before,
   navigate to the last line, and press X (capital x) to set all items in
   the range at once. Lowercase x has been added as a synonym for space to
   help reinforce the mechanism, and pressing enter/return continues to be a
   synonym for "toggle the current line and move down to the next item in
   this section."

== New Experimental Features ==

 * New config `experimental.log.topo` makes `hg log -G` use
   topological sorting. This is especially useful for aliases since it
   lets the alias accept an `-r` option while still using topological
   sorting with or without the `-r` (unlike if you use the `sort(...,
   topo)` revset).


== Bug Fixes  ==

 * issue4292: "hg log and {files} {file_adds} {file_mods} {file_dels}
   in template show wrong files on merged revision". See details in
   "Backwards Compatibility Changes".


== Backwards Compatibility Changes ==

 * Removed (experimental) support for log graph lines mixing
   parent/grandparent styles. Setting
   e.g. `experimental.graphstyle.parent = !` and
   `experimental.graphstyle.grandparent = 3.` would use `!` for the
   first three lines of the graph and then `.`. This is no longer
   supported.

 * If `ui.origbackuppath` had been (incorrectly) configured to point
   to a file, we will now replace that file by a directory and put
   backups in that directory. This is similar to how we would
   previously replace files *in* the configured directory by
   subdirectories.

* Template keyword `{file_mods}`, `{file_adds}`, and `{file_dels}`
   have changed behavior on merge commits. They used to be relative to
   the first parent, but they now consider both parents. `{file_adds}`
   shows files that exists in the commit but did not exist in either
   parent. `{file_dels}` shows files that do not exist in the commit
   but existed in either parent. `{file_mods}` show the remaining
   files from `{files}` that were not in the other two
   sets.


== Internal API Changes ==

 * Matchers are no longer iterable. Use `match.files()` instead.

 * `match.visitdir()` and `match.visitchildrenset()` now expect the
   empty string instead of '.' to indicate the root directory.

 * `util.dirs()` and `util.finddirs()` now include an entry for the
   root directory (empty string).

 * shelve is no longer an extension now. it will be turned on by default.

 * New API to manage unfinished operations: Earlier there were distinct APIs
   which dealt with unfinished states and separate lists maintaining them
   that are `cmdutil.afterresolvestates`, `cmdutil.unfinishedstates` and
   `cmdutil.STATES`. Now these have been unified to a single
   API which handles the various states and their utilities. This API
   has been added to `state.py`. Now instead of adding to these 3 lists
   independently a state for a new operation can be registered using
   `addunfinished()` in `state` module.

 * `cmdutil.checkunfinished()` now includes detection for merge too.

 * merge abort has been disallowed in case an operation of higher
   precedence is in progress to avoid cases of partial abort of
   operations.

 * We used to automatically attempt to make extensions compatible with
   Python 3 (by translating their source code while loading it). We no
   longer do that.