py3: fix headencode() with display=False We previously called str() on a email.header.Header object. On Python 2, this returns a bytestring and the __str__ method is actually an alias to .encode() method. On Python 3, __str__ does not perform encoding (and returns a unicode string). To keep a consistent behavior across Python versions, we explicitly use .encode() and we wrap the result with encoding.strtolocal() to get a bytestring in all cases. As a side effect of forcing bytes conversion, we need to decode back in _addressencode(). This is to make test-notify.t pass on Python 3. Also note that headers are now encoded in some patchbomb tests; this is because the charset is not always "us-ascii" ("iso-8859-1" otherwise) on Python 3.

mail: catch LookupError in headdecode() We already catch this exception in _encode() (called by headencode()). It gets raised when running test-notify.t with Python 3.

py3: account for extra line break in email headers in test-notify.t Long headers appears to be wrapped with new lines. In test-notify.t, we have a "filter.py" that replaces "\n" by " ", so we get an extra space in a Message-Id with a long value.

py3: use as_bytes() method of EmailMessage In Python 3, as_bytes() corresponds to as_string() in Python 2.

py3: use %d instead of %s when formatting an int into a bytestring The latter wasn't noticed before since no tests exercise --confirm at all, let alone on an existing DREV. The former is only hit during an intermittent network issue during amending at the end of a phabsend, so doesn't seem testable. Differential Revision: https://phab.mercurial-scm.org/D7153

packaging: ship only a single binary Debian package We merge the mercurial and mercurial-common binary packages into a single mercurial package. This is essentially to ease installation (and upgrade) using a simple "dpkg -i" command. This also simplifies debian/rules by removing arch (in)dependent cleanups during installation. We have the mercurial binary Breaks: and Replaces: mercurial-common so that the latter will be removed upon upgrade. Also note the change from "override_dh_install" to "override_dh_auto_install" in debian/rules: this is because we do not want "make install" to be run automatically as we need the --install-layout=deb of "setup.py install" (otherwise, files would end up in $DESTDIR/usr/local).