selector2: vendor selector2 library This library was a backport of the Python 3 "selectors" library. It is useful to provide a better selector interface for Python2, to address some issues of the plain old select.select, mentioned in the next patch. The code [1] was ported using the MIT license, with some minor modifications to make our test happy: 1. "# no-check-code" was added since it's foreign code. 2. "from __future__ import absolute_import" was added. 3. "from collections import namedtuple, Mapping" changed to avoid direct symbol import. [1]: https://github.com/SethMichaelLarson/selectors2/blob/d27dbd2fdc48331fb76ed431f44b6e6956de7f82/selectors2.py # no-check-commit

context: name files relative to cwd in warning messages I was several directories deep in the kernel tree, ran `hg add`, and got the warning about the size of one of the files. I noticed that it suggested undoing the add with a specific revert command. The problem is, it would have failed since the path printed was relative to the repo root instead of cwd. While here, I just fixed the other messages too. As an added benefit, these messages now look the same as the verbose/inexact messages for the corresponding command. I don't think most of these messages are reachable (typically the corresponding cmdutil function does the check). I wasn't able to figure out why the keyword tests were failing when using pathto()- I couldn't cause an absolute path to be used by manipulating the --cwd flag on a regular add. (I did notice that keyword is adding the file without holding wlock.)