merge: if DELETED_CHANGED and GET are in actions, choose DELETED_CHANGED ACTION_GET represents that either the file is created on remote or it's newer on the remote side. However, since we have a ACTION_DELETE_CHANGED too, it means the file is not present locally and ACTION_GET is representing that file was created on remote. Having both ACTION_GET and ACTION_DELETED_CHANGED is conflicting because one says that file was created on remote and other says file has delete-changed conflicts. Let's choose ACTION_DELETED_CHANGED which will result in conflicts and make user choose the right way forward.

tests: add newfilenode test case in test-merge-changedelete.t

rust: leverage improved match ergonomics Differential Revision: https://phab.mercurial-scm.org/D9137

rust: update minimum supported Rust compiler version Debian stable backported `rustc 1.41.1` for a Firefox release that needed it, so we can finally update the compiler version to something that isn't more than a year old. This means that (among other things [1]), `async await` syntax is usable! Differential Revision: https://phab.mercurial-scm.org/D9138

changing-files: add a utility to compute the merged files post-commit We will need it in `_getsidedata` as soon as we start persisting that set. Differential Revision: https://phab.mercurial-scm.org/D9089

changing-files: record merged files at commit time The data is easy to gather at commit time, and we need it for changeset centric copy tracing. Right now, it is not persisted so we cannot use it. However we will fix this part very soon, gathering something to persist was necessary first. Differential Revision: https://phab.mercurial-scm.org/D9088

changing-files: add the ability to track merged files too The set of merged files is used when doing changeset centric copy tracing (cf `is_merged` in `mercurial/copies.py`. So tracking (and persisting) this set will be useful. We start with adding the attribute on the new object. Differential Revision: https://phab.mercurial-scm.org/D9087

rust: start plugging the dirstate tree behind a feature gate The previous patch added the `dirstate-tree` feature gate to enable the two dirstate implementations to co-habit while the tree-based one gets better. This patch copies over the code that differs, be it because the algorithm changed or because the borrowing rules are different. Indeed, `DirstateTree` is not observationally equivalent to the std `HashMap` in the APIs we use: it does not have the `Entry` API (yet?) and its iterator returns owned values instead of references. This last point is because the implementation needs to be changed to a more clever and efficient solution. Differential Revision: https://phab.mercurial-scm.org/D9133

rust: introduce `dirstate-tree` cargo feature This feature gates (at compile-time) the use of the newly-added dirstate tree. The motivation for this is that the dirstate tree is currently *very* slow; replacing the current hashmap-based dirstate is not a viable solution in terms of performance... and why would you be using the Rust implementation if not for performance? The feature will also help reviewers better understand the differences that will slowly appear as the dirstate tree gets better. Differential Revision: https://phab.mercurial-scm.org/D9132

rust: fix formatting Maybe there is a small divergence in the nightly formatter? This didn't seem to trip the CI. Differential Revision: https://phab.mercurial-scm.org/D9131

rust-matchers: make `Matcher` trait object-safe Before this patch, it is not possible to create a `Matcher` trait-object (like `Box<dyn Matcher>`), because of the use of a generic parameters in some methods, namely `impl AsRef<HgPath>`. While this makes the interface less flexible for callers in theory, it does not change anything in the current codebase. Until something like [1] is implemented, this is a "tradeoff" that we need to make anyway. [1] https://internals.rust-lang.org/t/pre-rfc-expand-object-safety/12693 Differential Revision: https://phab.mercurial-scm.org/D9071

rust: clippy pass This removes some justified warnings and one hard error that, while technically not a bug, was an ugly oversight on my part. Differential Revision: https://phab.mercurial-scm.org/D9094

updaterepo: add deprecation warning We just moved all in-tree callers off of the function, but we're leaving it here for a bit to help extension writers. Differential Revision: https://phab.mercurial-scm.org/D9110

rhg: use `.or(Err(Error))` not `.map_err(|_| Error)` (D9100#inline-15067) Differential Revision: https://phab.mercurial-scm.org/D9109

hg-core: use `.or(Err(Error))` not `.map_err(|_| Error)` (D9100#inline-15067) Differential Revision: https://phab.mercurial-scm.org/D9108

hg-core: return Err if `offset != bytes.len()` (D8958#inline-14994 followup 2/2) [X] make `Index` owner of its bytes [X] make `Index::new` return an error if `offset != bytes.len()` Differential Revision: https://phab.mercurial-scm.org/D9107

hg-core: make `Index` owner of its bytes (D8958#inline-14994 followup 1/2) Prevent building `Index` every time it is needed. It was a bad idea anyway. When `Index::new` will return `Result` it will avoid things like `Revlog::len` returning `Result<usize>` instead of `usize`. [X] make `Index` owner of its bytes [ ] make `Index::new` return an error if `offset != bytes.len()` Differential Revision: https://phab.mercurial-scm.org/D9106

hg-core: renaming of `Chunk` offset methods (D8958#inline-15002 followup) Differential Revision: https://phab.mercurial-scm.org/D9105

hg-core: minor rewording in docstring (D8958#inline-15005 followup) Differential Revision: https://phab.mercurial-scm.org/D9104

hg-core: use anonymous lifetime for `impl Chunk` (D8958#inline-15003 followup) Differential Revision: https://phab.mercurial-scm.org/D9103

hg-core: use `u32` instead of `i32` in `Chunk` (D8958#inline-15001 followup) Differential Revision: https://phab.mercurial-scm.org/D9102

hg-core: use the term `chunk` instead of `frag` (D8958#inline-15000 followup) Differential Revision: https://phab.mercurial-scm.org/D9101

hg-core: return `Err` on decompression error (D8958#inline-15004 followup) Differential Revision: https://phab.mercurial-scm.org/D9100

hg-core: remove useless code (D8958#inline-14988 followup) Differential Revision: https://phab.mercurial-scm.org/D9099

hg-core: minor docstring update (D8958#inline-14991 followup) Differential Revision: https://phab.mercurial-scm.org/D9097

hg-core: minor code style change (D8958#inline-14986 followup) Differential Revision: https://phab.mercurial-scm.org/D9096

hg-core: Explain offset override of first revision (D8958#inline-14992 followup) Differential Revision: https://phab.mercurial-scm.org/D9095

hg-core: minor code style change (D8958#inline-14993 followup) Differential Revision: https://phab.mercurial-scm.org/D9083

changing-files: move default constructor value to None According to Augie Fackler, using tuple as default value confuse PyType when actual values are passed at init time. Differential Revision: https://phab.mercurial-scm.org/D9086

rust: format with rustfmt I suppose I ran the formatter on the tip but not on every patch. Differential Revision: https://phab.mercurial-scm.org/D9093