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.

rust-cpython: remove useless wrappers from PyLeaked, just move by map() This series prepares for migrating to the upstreamed version of PySharedRef. I found this last batch wasn't queued while rewriting the callers. While Option<T> was historically needed, it shouldn't be required anymore. I wasn't aware that each filed can be just moved.

rust-node: avoid meaningless read at the end of odd prefix This should be heavily factored out by the CPU branch predictor anyway. Differential Revision: https://phab.mercurial-scm.org/D8019

rust-nodemap: generic NodeTreeVisitor This iterator will help avoid code duplication when we'll implement `insert()`, in which we will need to traverse the node tree, and to remember the visited blocks. The structured iterator item will allow different usages from `lookup()` and the upcoming `insert()`. Differential Revision: https://phab.mercurial-scm.org/D7794

rust-nodemap: mutable NodeTree data structure Thanks to the previously indexing abstraction, the only difference in the lookup algorithm is that we don't need the special case for an empty NodeTree any more. We've considered making the mutable root an `Option<Block>`, but that leads to unpleasant checks and `unwrap()` unless we abstract it as typestate patterns (`NodeTree<Immutable>` and `NodeTree<Mutated>`) which seem exaggerated in that case. The initial copy of the root block is a very minor performance penalty, given that it typically occurs just once per transaction. Differential Revision: https://phab.mercurial-scm.org/D7793

rust-nodemap: abstracting the indexing In the forthcoming mutable implementation, we'll have to visit node trees that are more complex than a single slice, although the algorithm will still be expressed in simple indexing terms. We still refrain using `#[inline]` indications as being premature optimizations, but we strongly hope the compiler will indeed inline most of the glue. Differential Revision: https://phab.mercurial-scm.org/D7792

rust-nodemap: NodeMap trait with simplest implementation We're defining here only a small part of the immutable methods it will have at the end. This is so we can focus in the following changesets on the needed abstractions for a mutable append-only serializable version. The first implementor exposes the actual lookup algorithm in its simplest form. It will have to be expanded to account for the missing methods, and the special cases related to NULL_NODE. Differential Revision: https://phab.mercurial-scm.org/D7791

rust-node: handling binary Node prefix Parallel to the inner signatures of the nodetree functions in revlog.c, we'll have to handle prefixes of `Node` in binary form. Another motivation is that it allows to convert from full Node references to `NodePrefixRef` without copy. This is expected to be by far the most common case in practice. There's a slight complication due to the fact that we'll be sometimes interested in prefixes with an odd number of hexadecimal digits, which translates in binary form by a last byte in which only the highest weight 4 bits are considered. This is totally transparent for callers and could be revised once we have proper means to measure performance. The C implementation does the same, passing the length in nybbles as function arguments. Because Rust byte slices already have a length, we carry the even/odd informaton as a boolean, to avoid introducing logical redundancies and the related potential inconsistency bugs. There are a few candidates for inlining here, but we refrain from such premature optimizations, letting the compiler decide. Differential Revision: https://phab.mercurial-scm.org/D7790

rust-revlog: a trait for the revlog index As explained in the doc comment, this is the minimum needed for our immediate concern, which is to implement a nodemap in Rust. The trait will be later implemented in `hg-cpython` by the index Python object implemented in C, thanks to exposition of the corresponding functions as a capsule. The `None` return cases in `node()` match what the `index_node()` C function does. Differential Revision: https://phab.mercurial-scm.org/D7789

pathauditor: drop a redundant call to bytes.lower() `_lowerclean(s)` calls `s.lower()`, so we don't need to do that before calling it. Differential Revision: https://phab.mercurial-scm.org/D8001

merge: replace a repo.lookup('.') by more typical repo['.'].node() The `repo.lookup('.')` form comes from b3311e26f94f (merge: fix --preview to show all nodes that will be merged (issue2043)., 2010-02-15). I don't know why that commit changed from `repo['.']`, but I don't think there's any reason to do that. Note that performance should not be a reason (anymore?), because repo.lookup() is implemented by first creating a context object. Differential Revision: https://phab.mercurial-scm.org/D7998

merge: drop now-unused "abort" argument from hg.merge() Differential Revision: https://phab.mercurial-scm.org/D7997

merge: don't auto-pick destination with `hg merge 'wdir()'` If the user doesn't specify a commit to merge with, we'll have `node==None` in `commands.merge()`. We'll then try to find a good commit to merge with. However, if the user, for some strange reason, runs `hg merge 'wdir()'`, we'll also have `node==None` and we'll do that same. That's clearly not the intent, so let's not do that. It turns out we'd instead crash on that command after this patch, so I added special handling of it too. Differential Revision: https://phab.mercurial-scm.org/D7996

merge: call hg.abortmerge() directly and return early It's seem really weird to go through a lot of unrelated code before we call `hg.merge(..., abort=True)` when we can just call `hg.abortmerge()` and return early. Differential Revision: https://phab.mercurial-scm.org/D7995

merge: check that there are no conflicts after --abort Same idea as in abcc82bf0717 (clean: check that there are no conflicts after, 2020-01-24). We should reuse more code here, but that will come later. Differential Revision: https://phab.mercurial-scm.org/D7994

merge: use check_incompatible_arguments() for --abort Differential Revision: https://phab.mercurial-scm.org/D7993

wix: use original version string for MSI filename Version string normalization is mostly to placate MSI requirements. I think it makes sense to use the original version string in filenames. Since we can have distinct versions normalizing to the same MSI version string, this will allow us to distinguish between different actual version strings based on the filename. Differential Revision: https://phab.mercurial-scm.org/D8005

wix: always normalize version string Before, it was possible to pass in a custom version string which would not be valid in MSI. So we always normalize the version string. While we're here, also print when we normalize the version string, for better visibility. Differential Revision: https://phab.mercurial-scm.org/D8004

wix: more robust normalization of RC version components MSI has strict version requirements where the format is `A.B.C[.D]` and all fields must be numeric (https://docs.microsoft.com/en-us/windows/win32/msi/productversion?redirectedfrom=MSDN). Only the first 3 are used by the installer itself. Mercurial's version strings can have `rcN` and an optional `+<commit>-<date>` fragment at the end. This commit teaches the MSI version normalization to handle both of these more robustly. Before, we would throw away the `.rcN` component completely. e.g. `5.3rc1` would get normalized to `5.3.0`. And worse, `5.3rc0+5-abcdef` would get normalized to `5.3.5`. After this commit, presence of an `.rcN` provides the value for a 4th field. e.g. `5.3rc1` -> `5.3.0.1`. In addition, the commit count from the `+` suffix gets normalized into the 4th version component, but only if the original version string didn't have a 4th version component or if no `rcN` is present. e.g. `5.3+5-abcdef` is `5.3.0.5`. Differential Revision: https://phab.mercurial-scm.org/D8003

copyright: update to 2020 Differential Revision: https://phab.mercurial-scm.org/D8006

phabricator: fix a crash when submitting binaries (issue6260) I think this assumed that `p1()` returned the changectx instead of the previous filelog entry. Differential Revision: https://phab.mercurial-scm.org/D8010

rebase: move some variables after an error cases where they're not needed Differential Revision: https://phab.mercurial-scm.org/D7905

rebase: clarify a little by calculating a set in Python instead of in revset By calculating the set in Python, we can give it a name, which helps readability. Differential Revision: https://phab.mercurial-scm.org/D7904

merge: avoid a negation in the definition of updatedirstate We only use `partial` in one place: the definition of `updatedirstate`. Let's simplify that a little. Differential Revision: https://phab.mercurial-scm.org/D7900

merge: move definition of `partial` closer to where it's used Differential Revision: https://phab.mercurial-scm.org/D7983

copies: extract function for finding directory renames The directory rename code is logically quite isolated, so it makes sense to make it physically isolated as well. Differential Revision: https://phab.mercurial-scm.org/D7977

copies: avoid calculating debug-only stuff without --debug `renamedeleteset` and `divergeset` is only used with `repo.ui.debugflag`, so let's avoid calculating them otherwise. While at it, I also added a `del renamedeleteset` for consistency. Differential Revision: https://phab.mercurial-scm.org/D7976

copies: move early return in mergecopies() earlier It wasn't obvious that the early return happened only when there are no copies. That is the case, however, because if `fullcopy` is empty, then so is `copies1` and `copies2`, and then so is `inversecopies1` and `inversecopies2`, and then so is `allsources`, and then so is `copy`, `diverge` and `renamedelete`. By moving the early return earlier, we also avoid calculating the set of added files from the base to each side. Differential Revision: https://phab.mercurial-scm.org/D7975

tests: test merge of renames of different sources to same target This is a really obscure scenario, but let's still have it tested so we know when it changes. Differential Revision: https://phab.mercurial-scm.org/D7985

clean: check that there are no conflicts after As noted by Pulkit, there should never be any conflicts after doing a clean update, so `hg.clean()` should never return `True`. Let's check that assertion instead to clarify the code. The callers will now get a `None` instead of a `False` returned, but that should be fine (both result in a 0 exit status). Differential Revision: https://phab.mercurial-scm.org/D7984

progress: delete deprecated ui.progress() Differential Revision: https://phab.mercurial-scm.org/D7991

rust-dependencies: update rayon This is just to make sure we use the latest version and also makes it easier to peruse the docs. Differential Revision: https://phab.mercurial-scm.org/D7926