copies: move short-circuiting of dirstate copies out of _forwardcopies() I'd like to move the filtering of copies we do after chaining to the end of all chaining (in a single place in pathcopies()). One problem that came up when trying that was that we allow things like `hg cp -f <file> <existing file>` so the user can later amend that in. Filtering at the end would mean that we remove those copies. That would break `hg st -C`. This patch therefore moves the short-circuiting of dirstate copies into pathcopies() so we can more easily handle the dirstate-only case differently. I initially thought this might change some behavior when the user does `hg status --rev 'wdir()' --rev .` during an uncommitted merge, since _backwardrenames() would reverse the copies in that case. However, I couldn't come up with a test case where it made a difference. Differential Revision: https://phab.mercurial-scm.org/D6600

tests: add more tests of copy tracing with removed and re-added files We had a test where the destination of a copy was removed and then added back. This patch adds similar cases where the break in history instead happens to the source file. There are three versions of this: 1. The break happens before the rename. 2. The break happens on a branch parallel to the rename (where copy tracing is done via the merge base) 3. The source is added on each side of the merge base. The break in history is thus in the form of a deletion when going backwards to the merge base and the re-add happens on the other branch. I've also added calls to `hg graft` in these cases to show the breakage in issue 6163. Another factor in these cases is matching nodeid (checked in copies._tracefile()). I've made two copies each of the cases to show the impact of that. One of these is the same as a test in test-rename-merge1.t, so I also deleted that test from there. Some of these tests currently fail, where "fail" is based on my current thinking of how things should work. I had initially thought that we should be more strict about not tracing copies across commits where the file did not exist, but issue 6163 made me reconsider. The only test case here that behaved differently in 4.9 is the exact case reported in issue 6163. Differential Revision: https://phab.mercurial-scm.org/D6599

tests: split out tests for unrelated copy source/target into separate file I've realized only recently how many cases there are where a file is treated differently if it's considered "related" to another file (not deleted and re-added). I'll add more tests for some of these cases soon. Differential Revision: https://phab.mercurial-scm.org/D6598

subrepos: make last line of prompts <40 english chars (issue6158) Differential Revision: https://phab.mercurial-scm.org/D6572

largefiles: make last line of prompts <40 english chars (issue6158) Differential Revision: https://phab.mercurial-scm.org/D6571

rust-dirstate: add helper to iterate ancestor paths This is modeled after std::path::Path::ancestors(). find_dirs(b"") yields b"" because Mercurial's util.finddirs() works in that way, and the test case for DirsMultiset expects such behavior.