doc/common.txt

check-code: disallow use of hasattr()

The hasattr() builtin from Python < 3.2 [1] has slightly surprising
behavior: it catches all exceptions, even KeyboardInterrupt. This
causes it to have several surprising side effects, such as hiding
warnings that occur during attribute load and causing mysterious
failure modes when ^Cing an application. In later versions of Python
2.x [0], exception classes which do not inherit from Exception (such
as SystemExit and KeyboardInterrupt) are not caught, but other types
of exceptions may still silently cause returning False instead of
getting a reasonable exception.

[0] http://bugs.python.org/issue2196
[1] http://docs.python.org/dev/whatsnew/3.2.html

.. Common link and substitution definitions.

.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html