copies: make mergecopies() distinguish between copies on each side I find it confusing that most of the dicts returned from `mergecopies()` have entries specific to one branch of the merge, but they're still combined into dict. For example, you can't tell if `copy = {"bar": "foo"}` means that "foo" was copied to "bar" on the first branch or the second. It also feels like there are bugs lurking here because we may mistake which side the copy happened on. However, for most of the dicts, it's not possible that there is disagreement. For example, `renamedelete` keeps track of renames that happened on one side of the merge where the other side deleted the file. There can't be a disagreement there (because we record that in the `diverge` dict instead). For regular copies/renames, there can be a disagreement. Let's say file "foo" was copied to "bar" on one branch and file "baz" was copied to "bar" on the other. Beacause we only return one `copy` dict, we end up replacing the `{"bar": "foo"}` entry by `{"bar": "baz"}`. The merge code (`manifestmerge()`) will then decide that that means "both renamed from 'baz'". We should probably treat it as a conflict instead. The next few patches will make `mergecopies()` return two instances of most of the returned copies. That will lead to a bit more code (~40 lines), but I think it makes both `copies.mergecopies()` and `merge.manifestmerge()` clearer. Differential Revision: https://phab.mercurial-scm.org/D7986

pathutil: mark parent directories as audited as we go Before 0b7ce0b16d8a (pathauditor: change parts verification order to be root first, 2016-02-11), we used to validate child directories before parents. It was then important to only mark the child audited only after we had audited its parent (ancestors). I'm pretty sure we don't need to do that any more, now that we audit parents before children. Differential Revision: https://phab.mercurial-scm.org/D8002

cmdutil: change check_incompatible_arguments() *arg to single iterable This makes it clearer on the call-sites that the first argument is special. Thanks to Yuya for the suggestion. Differential Revision: https://phab.mercurial-scm.org/D8018

rust: remove an unnecessary set of parentheses My build complained about this. I guess it started after I upgraded rustc. Differential Revision: https://phab.mercurial-scm.org/D8020

profiling: flush stdout before writing profile to stderr On py3, stdout and stderr appear to be buffered and this causes my command's output to be intermixed with the profiling output. Differential Revision: https://phab.mercurial-scm.org/D8024

rust: re-format with nightly rustfmt This fixes test-check-rust-format.t. Differential Revision: https://phab.mercurial-scm.org/D8025

tests: stablize test-rename-merge1.t on Windows This goes with d7622fdec3b5. Differential Revision: https://phab.mercurial-scm.org/D8036

rust-cpython: make sure PySharedRef::borrow_mut() never panics Since it returns a Result, it shouldn't panic depending on where the borrowing fails. PySharedRef::borrow_mut() will be renamed to try_borrow_mut() by the next patch.