README.rst

rust-index: implement common_ancestors_heads() and ancestors()

The only differences betwwen `common_ancestors_heads()` and
`find_gca_candidates()` seems to be that:

- the former accepts "overlapping" input revisions (meaning with duplicates).
- limitation to 24 inputs (in the C code), that we translate to using the
  arbitrary size bit sets in the Rust code because we cannot bail to Python.

Given that the input is expected to be small in most cases, we take the
heavy handed approach of going through a HashSet and wait for perfomance
assessment

In case this is used via `hg-cpython`, we can anyway absorb the overhead
by having `commonancestorheads` build a vector of unique values
directly, and introduce a thin wrapper over `find_gca_candidates`, to take
care of bit set type dispatching only.

As far as `ancestors` is concerneed, this is just chaining
`common_ancestors_heads()` with `find_deepest_revs`.

Mercurial
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Mercurial is a fast, easy to use, distributed revision control tool
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Basic install::

 $ make            # see install targets
 $ make install    # do a system-wide install
 $ hg debuginstall # sanity-check setup
 $ hg              # see help

Running without installing::

 $ make local      # build for inplace usage
 $ ./hg --version  # should show the latest version

See https://mercurial-scm.org/ for detailed installation
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Notes for packagers
===================

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