= Mercurial 6.9rc0 =

/!\ These are release notes for a release candidate version. Any and all points can be reverted before the final release.

== New Features ==

 * exchange: improve computation of relevant markers for large repos
 * Add a Rust fast-path to speed up update (also for `clone`) from null (up to 4x faster) 
 * Introduced a new rev-branch-cache version (v2) that is mmap-resistant
 * The branchmap's performance was improved
 * Improved the performance of the fix for issue6528
 * clonebundles: allow manifest to specify sha256 digest of bundles
 * merge: improve working-copy mtime race handling
 * profiling: add a py-spy profiling backend
 * revlog: use an explicit config option to enable mmap usage for index
 * revlog: use mmap by default is pre-population is available
 * mmap: populate the mapping by default
 * mmap: populate mapping in a background thread

== Experimental features ==

 * merge: add a config to allow conflict-free merge of changes on adjacent lines

== Bug Fixes ==

 * `config.server.validate` now also works on narrowed repositories
 * convert: fix various leaked file descriptors
 * stream: prefer keeping an open file handle to volatile file instead of copy
 * dummysmtpd: fix EOF handling on newer versions of OpenSSL
 * cext: correct the argument handling of `b85encode()`
 * branchmap-v3: make sure we write the cache after detecting pure-topo mode
 * rust: apply clippy lints
 * copies: make sure deleted copy info do not overwriting unrelated ones
 * rebase: don't call rewriteutil.precheck() with to-be-skipped commits
 * phabricator: correct the default value of `phabhunk.corpus`
 * linelog: correct the default value of `annotateresult.lines`
 * largefiles: avoid a potentially undefined variable in exception case
 * httppeer: move a variable to avoid a bad reference before assignment warning
 * httppeer: avoid another bad reference before assignment warning
 * tests: use packaging from setuptools instead of deprecated distutils
 * manifest: type and fix unhexlify
 * manifest: align some vfs option access on the fact we might not have options
 * scmutils: read the requires file before writing to avoid unnecessary rewrite
 * debugsparse: stop taking the store lock
 * sparse: reliably avoid writing to store without a lock
 * largefiles: sync up `largefilesdirstate` methods with `dirstate` base class
 * shelve: raise an error when loading a corrupt state file in an impossible case
 * monotone: replace %s interpolation with appropriate numeric specifiers
 * shelve: consistently convert exception to bytes via `stringutil.forcebytestr`
 * remotefilelog: honor the `--format` arg of the `debugindex` command
 * remotefilelog: adapt the `debugindex` command to past API changes
 * run-tests: add color to the progress output
 * archive: defer opening the output until a file is matched
 * help: add :config-doc:`section.key` shorthand to insert documentation
 * censor: document the censor.policy option (issue6909)
 * rust-revlog: don't try to open the data file if the index is empty
 * bundlerepo: fix mismatches with repository and revlog classes
 * revlog: make `clearcaches()` signature consistent with ManifestRevlog
 * unionrepo: fix mismatches with revlog classes
 * keepalive: fix a signature mismatch for a http.client.HTTPResponse subclass
 * lfs: fix various signature mismatches for vfs subclasses
 * store: fix a signature mismatch for a vfs subclass
 * util: avoid a leaked file descriptor in `util.makelock()` exceptional case
 * statichttprepo: fix `httprangereader.read()` for py3
 * util: make `mmapread()` work on Windows again
 * mdiff: tweak calls into `bdiff.fixws` to match its type hints
 * base85: avoid a spurious use-before-initialized warning in `pure` module
 * install: static data moved from setup.py to pyproject.toml
 * upgrade: disable using the parallel workers optimization on macOS
 * doc: generate separate commands/topics/extension pages
 * extdiff: don't run gui programs when in a cli-only environment
 * clonebundles: stop shell quoting `HGCB_BUNDLE_BASENAME` environment variable
 * rev-branch-cache: disable mmapping by default on Windows

== Backwards Compatibility Changes ==

 * This release drops support for Python 3.6 and 3.7.

== Internal API Changes ==

 * manifest: deprecated readdelta and readfast

== Miscellaneous ==

 * http: reuse Python's implementation of read/readline/readinto
 * http: use urllib's cookie handler
 * rev-branch-cache: schedule a write of the "v2" format if we read from "v1"
 * rev-branch-cache: have debugupdatecache warm rbc too
 * rev-branch-cache: reenable memory mapping of the revision data
 * debugwireproto: redo logging to also work for https
 * rust: use `.cargo/config.toml` instead of `.cargo/config`
 * A whole bunch of typing improvements, which in turn found many bugs
 * Test suite improvements
 * Various packaging improvements