push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
== 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.