[PATCH WIP] help: show help content for disabled extension

[Yuya Nishihara]

On Mon, 31 Oct 2016 23:44:27 +0530, Pulkit Goyal wrote:
> On Sat, Oct 22, 2016 at 1:38 PM, Yuya Nishihara <yuya at tcha.org> wrote:
> > On Fri, 21 Oct 2016 09:13:11 -0400, timeless wrote:
> >> Have we considered supporting `hg help churn.churn` where the first
> >> churn is a (possibly) disabled extension name, and the second is the
> >> name of a command within that extension?
> >
> > Not yet?
> 
> Well working on issue5228, I found that we support something like `hg
> help qrecord` and
> if record extension is not enabled it will say,
> 
> 'qrecord' is provided by the following extension:
> 
>     record        commands to interactively select changes for commit/qrefresh
>                   (DEPRECATED)
> (use 'hg help extensions' for information on enabling extensions)
> 
> We support saying that this command is provided by the following
> extension, if the
> extension is disabled.

Yep, we try importing all extension modules to provide this message. That's
why "hg unknown-command" is slow. I don't think we should reuse this hack
to provide the help of disabled extensions since that would mean disabled
modules could be loaded into long-running hgweb processes.