dirstate-tree: optimize HashMap lookups with raw_entry_mut This switches to using `HashMap` from the hashbrown crate, in order to use its `raw_entry_mut` method. The standard library’s `HashMap` is also based on this same crate, but `raw_entry_mut` is not yet stable there: https://github.com/rust-lang/rust/issues/56167 Using version 0.9 because 0.10 is yanked and 0.11 requires Rust 1.49 This replaces in `DirstateMap::get_or_insert_node` a call to `HashMap<K, V>::entry` with `K = WithBasename<Cow<'on_disk, HgPath>>`. `entry` takes and consumes an "owned" `key: K` parameter, in case a new entry ends up inserted. This key is converted by `to_cow` from a value that borrows the `'path` lifetime. When this function is called by `Dirstate::new_v1`, `'path` is in fact the same as `'on_disk` so `to_cow` can return an owned key that contains `Cow::Borrowed`. For other callers, `to_cow` needs to create a `Cow::Owned` and thus make a costly heap memory allocation. This is wasteful if this key was already present in the map. Even when inserting a new node this is typically the case for its ancestor nodes (assuming most directories have numerous descendants). Differential Revision: https://phab.mercurial-scm.org/D12317

syntax: glob

*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/artifacts/cache/big-file-churn.hg
tests/.coverage*
tests/.testtimes*
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/exceptions
tests/python3
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.vscode/*
.idea/*
.asv/*
.pytype/*
.mypy_cache
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py

rust/target/
rust/*/target/

# Generated wheels
wheelhouse/

syntax: rootglob
# See Profiling in rust/README.rst
.cargo/config

syntax: regexp
^\.pc/
^\.(pydev)?project

# hackable windows distribution additions
^hg-python
^hg.py$