view CONTRIBUTING @ 45375:8c466bcb0879

revert: remove dangerous `parents` argument from `cmdutil.revert()`

As we found out the hard way (thanks to spectral@ for figuring it
out!), `cmdutil.revert()`'s `parents` argument must be
`repo.dirstate.parents()` or things may go wrong. We had an extension
that passed in the target commit as the first parent. The `hg split`
command from the evolve extension seems to have made the same mistake,
but I haven't looked carefully.

The problem is that `cmdutil._performrevert()` calls
`dirstate.normal()` on reverted files if the commit to revert to
equals the first parent. So if you pass in `ctx=foo` and
`parents=(foo.node(), nullid)`, then `dirstate.normal()` will be
called for the revert files, even though they might not be clean in
the working copy.

There doesn't seem to be any reason, other than a tiny performance
benefit, to passing the `parents` around instead of looking them up
again in `cmdutil._performrevert()`, so that's what this patch does.

Differential Revision: https://phab.mercurial-scm.org/D8925

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