commit: use `dirstate.change_files` to scope the associated `addremove`
This was significantly more complicated than I expected, because multiple
extensions get in the way.
I introduced a context that lazily open the transaction and associated context
to work around these complication. See the inline documentation for details.
Introducing the wrapping transaction remove the need for dirstate-guard (one of
the ultimate goal of all this), and slightly affect the result of a `hg
rollback` after a `hg commit --addremove`. That last part is deemed fine. It
aligns the behavior with what happens after a failed `hg commit --addremove` and
nobody should be using `hg rollback` anyway.
The small output change in the test come from the different transaction timing
and fact the transaction now backup the dirstate before the addremove, which
might mean "no file to backup" when the repository starts from an empty state.
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
new changesets d326ae2d01ee (1 drafts)
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
new changesets d326ae2d01ee (1 drafts)
4 files updated, 0 files merged, 0 files removed, 0 files unresolved