view relnotes/6.1 @ 49790:f463eb675e85 stable

emitrevision: consider ancestors revision to emit as available base

This should make more delta base valid. This notably affects:

* case where we skipped some parent with empty delta to directly delta against
  an ancestors
* case where an intermediate snapshots is stored.

This change means we could sent largish intermediate snapshots over the wire.
However this is actually a sub goal here. Sending snapshots over the wire means
the client have a high odd of simply storing the pre-computed delta instead of
doing a lengthy process that will… end up doing the same intermediate snapshot.

In addition the overall size of snapshot (or any level) is "only" some or the
overall delta size. (0.17% for my mercurial clone, 20% for my clone of Mozilla
try). So Sending them other the wire is unlikely to change large impact on the
bandwidth used.

If we decide that minimising the bandwidth is an explicit goal, we should
introduce new logic to filter-out snapshot as delta. The current code has no
notion explicite of snapshot so far, they just tended to fall into the wobbly
filtering options.

In some cases, this patch can yield large improvement to the bundling time:

    ### data-env-vars.name      = mozilla-try-2019-02-18-zstd-sparse-revlog
      # benchmark.name          = perf-bundle
      # benchmark.variants.revs = last-100000
    before: 68.787066 seconds
    after:  47.552677 seconds (-30.87%)

That translate to large improvement to the pull time :

    ### data-env-vars.name           = mozilla-try-2019-02-18-zstd-sparse-revlog
      # benchmark.name               = pull
      # benchmark.variants.issue6528 = disabled
      # benchmark.variants.revs      = last-100000
    before: 142.186625 seconds
    after:   75.897745 seconds  (-46.62%)

No significant negative impact have been observed.

'''This is the last release to support Python 2. Mercurial is Python 3 only starting with 6.2'''

= Mercurial 6.1.4 =

 * url: raise error if CONNECT request to proxy was unsuccessful
 * docker: avoid /tmp write access issues by fixing permissions
 * logcmdutil: use the same data as {file*} template keywords (issue6642)
 * commit: allow to close branch when committing change over a closed head
 * rust-status: don't trigger dirstate v1 rewrite when only v2 data is changed
 * purge: prevent a silly crash with --confirm --files
 * rust: relax im-rc dependency to allow minor updates"
 * Improve PyPy support
 * Improve Py3 error handling
 * Documentation fixes

= Mercurial 6.1.3 =

'''security: '''
 * narrow_widen_acl: enforce narrowacl in narrow_widen (SEC) 6b10151b9621

'''normal notes: '''
 * censor: fix [hg update] away from a revision with censored files
 * amend: stop losing copies when amending
 * rhg: strengthen dirstate v2 writing in broken filesystems
 * work around some broken DLL imports in Windows
 * worker: adapt _blockingreader to work around a python3.8.[0-1] bug (issue6444)
 * rhg: correctly handle the case where diffs are encoded relative to nullrev
 * fix bugs and race-conditions in the Mercurial test runner
 * chg: ignore already closed fds when cleaning up

= Mercurial 6.1.2 =

 * Improve Windows test suite
 * Fix `debuglock` not ignoring a missing lockfile when forcing a lock
 * Improve help of `ui.large-file-limit`
 * Set the large-file-limit to 10MB (from 10MiB) for clarity
 * While rewriting desc hashes, ignore ambiguous prefix "hashes"
 * Fix a crash in partial amend with copies
 * Fix a py3 compatiblity bug
 * Fix incorrect metadata causing dirstate-v2 data loss in edge case
 * Fix cleanup of old dirstate-v2 data files when using `rhg`
 * Make reference to `.hg/last_message.txt` relative in commit
 * Fix an infinite hang when `rhg` is used in the background
 * Fix Python DLL loading bug in Windows
 * Add `--docket` flag to `debugstate` to check out dirstate-v2 metadata
 * Remove `debugdirstateignorepatternhash` in favor of `debugstate --docket`
 * Fix incorrect metadata causing systematic complete dirstate-v2 rewrite

= Mercurial 6.1.1 =

 * Fix Rust compilation on `aarcch64`
 * Fix Rust compilation on architectures where `char` is unsigned
 * When the merge tool uses `$output`, don't leave markers in `$local`
 * Improve test suite support on big-endian platforms
 * Cap the number of concurrent threads to 16 in Rust `hg status` to prevent huge speed regression at higher thread counts
 * Fix `amend` with copies in extras
 * Abort if commit we're trying to `unamend` was not created by `hg [un]amend`
 * Fix file name in the pullbundle help text
 * Fix an issue with data not being correctly reset in the C implementation of dirstate-v2
 * Fix issue6673 where some tags were missing from cache after a merge
 * Fix stream-cloning a repo with empty requirements
 * Fix a false warning about content-divergence creation
 * Fix silly blackbox entries when hg is interrupted
 * Fix unsoundness (no known exploits) in Rust extensions (see cfd270d83169 and dd6b67d5c256)
 * Fix Rust dirstate counters not being updated correctly leading to some potential bugs (none known)
 * Stop relying on a compiler implementation detail in Rust HgPath

= Mercurial 6.1 =

== New Features ==
  * Added a way of specifying required extensions that prevent Mercurial from starting if they are not found. See `hg help config.extensions`.
  * Merge conflict markers have been made clearer (see backwards compatibility below)
  * Improve detailed error codes
  * Added a hint about mangled whitespace on bad patch
  * Explain which order the commits are presented in `chistedit`
  * Introduce a `dirstate-tracked-hint` feature to help automation keep track of changes to tracked files. See `hg help config.use-dirstate-tracked-hint`.
  * Shared repositories can be upgraded if the upgrade is specific to the share. For now, this only applies to `dirstate-v2` and `dirstate-tracked-hint`.
  * When using the `narrow` extension, non-conflicting changes to files outside of the narrow specification can now be merged.
  * When cloning a repository using stream-clone, the client can now control the repository format variants to use as long as the stream content does not restrict that variant.

== Default Format Change ==

These changes affect newly created repositories (or new clones) done with Mercurial 6.1.

  * The `share-safe` format variant is now enabled by default. It makes configuration and requirements more consistent across repository and their shares. This introduces a behavior change as shares from a repository using the new format will also use their main repository's configuration. See `hg help config.format.use-share-safe` for details about the feature and the available options for auto-upgrading existing shares.


== New Experimental Features ==
  * The pure Rust version of Mercurial called `rhg` added support for most common invocations of `hg status`. See `hg help rust.rhg` for details on how to try it out.
  * `rhg` supports narrow clones and sparse checkouts.

== Bug Fixes ==

  * '''Obsolete revisions are skipped while computing heads. In conjunction with the `evolve` extension >= 10.5.0, this leads to massive exchange (push/pull) speedups in repositories with a lot of heads and/or obsolete revisions.'''
  * Stream-clones now properly advertise all requirements needed. This can result in the stream-clone feature being disabled for some clients using < 6.0.2. A small bugfix patch for these older client is available if necessary.
  * The `--no-check` and `--no-merge` flags now properly overwrite the behavior from `commands.update.check`
  * `rhg`'s fallback detection is more robust in general in the presence of more advanced configs
  * `rhg`'s `blackbox` now supports milliseconds by default and uses the same ISO 8601 format as the Python implementation
  * Fix `rhg` crash on non-generaldelta revlogs
  * The `lfs`, `largefiles` and `sparse` extensions now correctly take the appropriate lock before writing requirements 
  * The `notify` extension does not produce errors anymore if a revision is not found
  * Remove unnecessary and overly strict check for divergence in `hg fix`
  * Windows compatibility improvements
  * Miscellaneous Python 3 and typing improvements
  * Many other small or internal fixes

== Backwards Compatibility Changes ==

  * The use of `share-safe`, means shares (of new repositories) will also use their main repository's configuration see the `Default Format Change` section for details.
  * The fix to stream-clone requirements advertising means some requirements previously (wrongly) omitted are now sent. This can confuse client using a Mercurial version < 6.0.2. The client would consider these requirements unsupported even if it actually know them. If you encounter this, either upgrade your client or apply the necessary patch.
  * The labels passed to merge tools have changed slightly. Merge tools can get labels passed to them if you include `$labellocal`, `$labelbase`, and/or `$labelother` in the `merge-tool.<tool name>.args` configuration. These labels used to have some space-padding, and truncation to fit within 72 columns. Both the padding and the truncation has been removed.
  * Some of the text in labels passed to merge tools has changed. For example, in conflicts while running `hg histedit`, the labels used to be "local", "base", and "histedit". They are now "already edited", "parent of current change", and "current change", respectively.
  * The computation of namedbranch heads now ignores obsolete revisions. User of the Changeset Evolution feature may see a change in location and numbers of heads of each named branches (and topic).
  * The remotefilelog extension now requires an appropriate excludepattern for subrepositories.
  * `debugsparse`'s interface has been reworked to be more flexible. Since it's a debug command it is not actually a breaking change, but it is worth noting here.
  * Temporary files for merges are now all inside a `hgmerge` directory instead of at the root of `TMPDIR`. The corresponding experimental `mergetempdirprefix` config option has been removed.

== Internal API Changes ==

  * The dirstate API received minor modifications.

== Miscellaneous ==

  * Removed exchange-v2. It was a prototype that had never been in a working state and had been left untouched since 2017.