relnotes/5.4

packaging: use PyOxidizer for producing WiX MSI installer

We recently taught our in-tree PyOxidizer configuration file to
produce MSI installers with WiX using PyOxidizer's built-in
support for doing so.

This commit changes our WiX + PyOxidizer installer generation
code to use this functionality.

After this change, all the Python packaging code is doing is the
following:

* Building HTML documentation
* Making gettext available to the build process.
* Munging CLI arguments to variables for the `pyoxidizer` execution.
* Invoking `pyoxidizer build`.
* Copying the produced `.msi` to the `dist/` directory.

Applying this stack on stable and rebuilding the 5.8 MSI installer
produced the following differences from the official 5.8 installer:

* .exe and .pyd files aren't byte identical (this is expected).
* Various .dist-info/ directories have different names due to older
  versions of PyOxidizer being buggy and not properly normalizing
  package names. (The new behavior is correct.)
* Various *.dist-info/RECORD files are different due to content
  divergence of files (this is expected).
* The python38.dll differs due to newer PyOxidizer shipping a newer
  version of Python 3.8.
* We now ship python3.dll because PyOxidizer now includes this file
  by default.
* The vcruntime140.dll differs because newer PyOxidizer installs a newer
  version. We also now ship a vcruntime140_1.dll because newer versions
  of the redistributable ship 2 files now.

The WiX GUIDs and IDs of installed files have likely changed as a
result of PyOxidizer's different mechanism for generating those
identifiers. This means that an upgrade install of the MSI will
replace files instead of doing an incremental update. This is
likely harmless and we've incurred this kind of breakage before.

As far as I can tell, the new PyOxidizer-built MSI is functionally
equivalent to the old method. Once we drop support for Python 2.7
MSI installers, we can delete the WiX code from the repository.

This commit temporarily drops support for extra `.wxs` files. We
raise an exception instead of silently not using them, which I think
is appropriate. We should be able to add support back in by injecting
state into pyoxidizer.bzl via `--var`. I just didn't want to expend
cognitive load to think about the solution as part of this series.

Differential Revision: https://phab.mercurial-scm.org/D10688

== New Features ==

 * `hg purge`/`hg clean` can now delete ignored files instead of
   untracked files, with the new -i flag.

 * `hg pull` now has a `--confirm` flag to prompt before applying changes.
   Config option `pull.confirm` is also added for that.

 * `hg log` now defaults to using an '%' symbol for commits involved
    in unresolved merge conflicts. That includes unresolved conflicts
    caused by e.g. `hg update --merge` and `hg graft`. '@' still takes
    precedence, so what used to be marked '@' still is.

 * New `conflictlocal()` and `conflictother()` revsets return the
   commits that are being merged, when there are conflicts. Also works
   for conflicts caused by e.g. `hg graft`.

 * `hg copy --forget` can be used to unmark a file as copied.

 * The `format.revlog-compression` configuration entry now accept a list. The
   first available option will be used. for example setting::

     [format]
     revlog-compression=zstd, zlib

   Will use `zstd` compression for new repositories is available, and will
   simply fall back to `zlib` if not.

 * `hg debugmergestate` output is now templated, which may be useful
   e.g. for IDEs that want to help the user resolve merge conflicts.


== New Experimental Features ==

 * `hg copy` now supports a `--at-rev` argument to mark files as
   copied in the specified commit. It only works with `--after` for
   now (i.e., it's only useful for marking files copied using non-hg
   `cp` as copied).

 * Use `hg copy --forget --at-rev REV` to unmark already committed
   copies.

== Bug Fixes  ==

 * Fix server exception when concurrent pushes delete the same bookmark

 * Prevent pushes of divergent bookmarks (foo@remote)

 * The push error "remote repository changed while pushing - please
   try again" now only happens when a concurrent push changed related
   heads (instead of when a concurrent pushed any revision).


== Backwards Compatibility Changes ==

 * When `hg rebase` pauses for merge conflict resolution, the working
   copy will no longer have the rebased node as a second parent. You
   can use the new `conflictparents()` revset for finding the other
   parent during a conflict.

 * `hg rebase` now accepts repeated `--source` and `--base`
   arguments. For example, `hg rebase --source 'A + B'` is equivalent
   to `hg rebase --source A --source B`. This is a
   backwards-incompatible change because it will break overriding an
   alias `myrebase = rebase --source A` by `hg myrebase --source B`
   (it will now rebase `(A + B)::` instead of `B::`).

 * `hg recover` does not verify the validity of the whole repository
   anymore. You can pass `--verify` or call `hg verify` if necessary.

 * `hg debugmergestate` output format changed. Let us know if that is
   causing you problems and we'll roll it back.

 * Resolved merge conflicts are now cleared by `hg commit` even if the
   working copy has no changes.


== Internal API Changes ==

 * The deprecated `ui.progress()` has now been deleted. Please use
   `ui.makeprogress()` instead.

 * `hg.merge()` now takes a `ctx` instead of the previous `repo` and
   `node` arguments.

 * `hg.merge()` has lost its `abort` argument. Please call
   `hg.abortmerge()` directly instead.

 * `hg.merge()` has lost its `mergeforce` argument. It should have
   only ever been called with the same value as the `force` argument.

 * The `*others` argument of `cmdutil.check_incompatible_arguments()`
   changed from being varargs argument to being a single collection.