graftcopies: document why the function is useful at all Despite having spent a significant amount on time on the copy-tracing code, I thought `graftcopies()` (formerly known as `duplicatecopies()`) was needed to duplicate copies after calling `merge.update()` to do a merge (as `merge.graft()` does), but it's actually usually not needed; `merge.update()` takes care of most copies. This patch documents what the function is for. Differential Revision: https://phab.mercurial-scm.org/D7861

graftcopies: remove `skip` and `repo` arguments The `skip` argument was added in 2ba6c9b4e0eb (rebase: fix bug that caused transitive copy records to disappear (issue4192), 2014-06-07) in order to fix https://bz.mercurial-scm.org/show_bug.cgi?id=4192. I ran tests at that commit without the `skiprev` argument and the only difference I noticed was that `test-rebase-collapse.t` failed differently, in the call that is now on line 501. Without the `skiprev` argument, that call would end up creating another commit because it tried to record an invalid copy. With the previous patch in this series, such invalid copies are no longer recorded, so it seems we don't need the `skip` argument anymore. I also removed the `repo` argument since that also becomes unused with the removal of the `skip` argument. Differential Revision: https://phab.mercurial-scm.org/D7860

graftcopies: use _filter() for filtering out invalid copies `graftcopies()` (formerly called `duplicatecopies()`) checked that the copy destination existed in the working copy, but it didn't check that copy source existed in the parent of the working copy. In `test-graft.t` we can see that as warnings about not finding ancestors of the copied files, and also empty commits getting created. This patch uses the existing `_filter()` function for filtering out invalid copies. In addition to the aforementioned types, that also includes copies where source and destination is the same. Differential Revision: https://phab.mercurial-scm.org/D7859

copies: replace duplicatecopies() by function that takes contexts The callers mostly have context objects, so let's avoid looking up the same context objects inside `duplicatecopies()`. I also renamed the function to `graftcopies()` since I think that better matches its purpose. I did it in the same commit so it's easier for extensions to switch between the functions. Differential Revision: https://phab.mercurial-scm.org/D7858

graft: extract repo[None] to a variable I plan to allow the caller pass in an overlayworkingctx, so this prepares for that. Differential Revision: https://phab.mercurial-scm.org/D7857

rust-core: fix typo in comment Differential Revision: https://phab.mercurial-scm.org/D7895