comparison mercurial/formatter.py @ 36445:e8d37838f5df

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.

36444:717a279c0c21

    def _renderitem(self, part, item):
        if part not in self._parts:
            return
        ref = self._parts[part]

        # TODO: add support for filectx. probably each template keyword or
        # function will have to declare dependent resources. e.g.
        # @templatekeyword(..., requires=('ctx',))
        props = {}
        # explicitly-defined fields precede templatekw
        props.update(item)
        if 'ctx' in item:
            # but template resources must be always available

36445:e8d37838f5df

    def _renderitem(self, part, item):
        if part not in self._parts:
            return
        ref = self._parts[part]

        # TODO: add support for filectx
        props = {}
        # explicitly-defined fields precede templatekw
        props.update(item)
        if 'ctx' in item:
            # but template resources must be always available