py3: use encoding.strtolocal() to convert str to bytes Differential Revision: https://phab.mercurial-scm.org/D2459

py3: use email.utils module instead of email.Utils On py2: >>> import email >>> import email.utils as eutil >>> email.Utils.parseaddr is eutil.parseaddr True >>> email.Utils.formatdate is eutil.formatdate True email.Utils is not present on Python 3. Differential Revision: https://phab.mercurial-scm.org/D2453

py3: slice over bytes or use .startswith() to prevent getting ascii values Differential Revision: https://phab.mercurial-scm.org/D2457

py3: use '%d' for integers instead of '%s' Differential Revision: https://phab.mercurial-scm.org/D2455

templatekw: add 'requires' flag to switch to exception-safe interface The current templatekw interface, f(repo, ctx, templ, **args), is horrible because it's quite easy to encounter TypeError, ValueError, etc. It's also bad for Python 3 porting due to the **kwargs issue. This patch introduces a flag to switch to new f(context, mapping) API seen in templater functions. The requirement spec isn't verified (yet) because context.resource() can gracefully raise a ResourceUnavailable exception, but it's planned to be used as a filter in the help, such as "Revision Keywords" (if 'ctx' in requires), "File Keywords" (if 'fctx' in requires), etc. showauthor() is ported to the new API as an example. 20 more follows.

templater: specialize ResourceUnavailable error so that it can be caught See the next patch how it will be used.

templater: move specialized exception types to top I'm going to add one more exception type.