[PATCH 1 of 2 resend] templater: add inheritance support to style maps

[Yuya Nishihara]

On Thu, 18 Aug 2016 13:15:05 -0500, Matt Mackall wrote:
> # HG changeset patch
> # User Matt Mackall <mpm at selenic.com>
> # Date 1471459227 18000
> #      Wed Aug 17 13:40:27 2016 -0500
> # Node ID 1f402560299be8692c767db1469afb6618adee81
> # Parent  b1809f5d7630a3fff0fa715bbd30dba0f07672a8
> templater: add inheritance support to style maps
> 
> We can now specify a base map file:
> 
> __base__ = path/to/map/file
> 
> That map file will be read and used to populate unset elements of the
> current map. Unlike using %include, elements in the inherited class
> will be read relative to that path.
> 
> This makes it much easier to make custom local tweaks to a style.

Queued the series, thanks. The existing behavior of %include is unfortunate.

> diff -r b1809f5d7630 -r 1f402560299b mercurial/templater.py
> --- a/mercurial/templater.py	Mon Aug 15 20:39:33 2016 -0700
> +++ b/mercurial/templater.py	Wed Aug 17 13:40:27 2016 -0500
> @@ -1026,6 +1026,16 @@
>                  raise error.ParseError(_('unmatched quotes'),
>                                         conf.source('', key))
>              cache[key] = unquotestring(val)
> +        elif key == "__base__":
> +            # treat as a pointer to a base class for this style
> +            path = util.normpath(os.path.join(base, val))
> +            bcache, btmap = _readmapfile(path)

Do we want to make __base__ look for templatepaths?