view relnotes/5.6 @ 45882:8cc9e7f762d6

errors: move similarity_hint() to error module

I want to be able to reuse it from `UnknownIdentifier`'s constructor.

Moving it results in a new import of `difflib` in the `error`
module. There was a comment at the top of `error.py` saying "Do not
import anything but pycompat here, please", which was added (except
for the "pycompat" bit) in 08cabecfa8a8 (errors: move revlog errors,
2009-01-11). I don't know the reason for the comment. I'm guessing the
point was to not make the module depend on other Mercurial modules. If
that was it, then importing `difflib` should be fine.

Sorry about the churn (I moved this code from the `dispatch` module to
the `scmutil` module very recently).

Differential Revision: https://phab.mercurial-scm.org/D9345

== New Features ==

 * `hg mv -A` can now be used with `--at-rev`. It behaves just like
   `hg cp -A --at-rev`, i.e. it marks the destination as a copy of the
   source whether or not the source still exists (but the source must
   exist in the parent revision).

 * New revset predicate `diffcontains(pattern)` for filtering revisions
   in the same way as `hg grep --diff pattern`.

 * The memory footprint per changeset and per file during pull/unbundle
   operations has been significantly reduced.


== New Experimental Features ==



== Bug Fixes ==



== Backwards Compatibility Changes ==



== Internal API Changes ==

 * `merge.update()` is now private (renamed to `_update()`). Hopefully
   the higher-level functions available in the same module cover your
   use cases.

 * `phases.registernew` now takes a set of revisions instead of a list
   of nodes. `phases.advanceboundary` takes an optional set of revisions
   in addition to the list of nodes. The corresponeding members of the
   `phasecache` class follow this change.

 * The `addgroup` member of `revlog` classes no longer keeps a list of
   all found nodes. It now returns True iff a node was found in the group.
   An optional callback for duplicated nodes can be used by callers to keep
   track of all nodes themselve.

 * The `_chaininfocache` of `revlog` classes has been changed from a dict
   to a LRU cache.