D5094: merge-tools: when calling external merge tool, describe the resolve inputs

[spectral (Kyle Lippincott)]

spectral added a comment.


  In https://phab.mercurial-scm.org/D5094#77146, @yuja wrote:
  
  > >   > We might want to structure these variables as `base.node|short` instead of
  > >   >  `base_node` for example, but that would require more work.
  >
  > [...]
  >
  > >   Unfortunately, this doesn't work super well, when using the following flags:
  >
  > There isn't a building block for a mapping dict holding mapping dicts, and
  >  the formatter API doesn't support such structure either.
  >
  > Fortunately, we don't need a formatter here since we just want to apply
  >  a template to a single item. So if we had a wrapper for a single mapping
  >  dict, the templater can be rendered as follows:
  >
  >   props = {
  >       'base': templateutil.mappingdict({'ctx': fca.changectx(), 'fctx': fca,
  >                                         'label': baselabel})
  >       ...
  >   }
  >   cmdutil.rendertemplate(fcd.changectx(), tmpl, props)
  >
  >
  > And `base.path`, `base.node`, etc. should just work.
  
  
  Done.
  
  > I'll post the dict wrapper if you like the idea.
  > 
  >   class mappingdict(mappable, _mappingsequence):
  >       """Wrapper for a single template mapping
  >   
  >       This isn't a sequence in a way that the underlying dict won't be iterated
  >       as a dict, but shares most of the _mappingsequence functions.
  >       """
  >   
  >       def __init__(self, mapping, name=None, tmpl=None):
  >           super(mappingdict, self).__init__(name, tmpl)
  >           self._mapping = mapping
  >   
  >       def tomap(self, context):
  >           return self._mapping
  >   
  >       def tobool(self, context, mapping):
  >           # no idea when a template mapping should be considered an empty, but
  >           # a mapping dict should have at least one item in practice, so always
  >           # mark this as non-empty.
  >           return True
  >   
  >       def tovalue(self, context, mapping):
  >           return super(mappingdict, self).tovalue(context, mapping)[0]
  
  I copy/pasted this to https://phab.mercurial-scm.org/D5211. :)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5094

To: spectral, #hg-reviewers
Cc: yuja, mjpieters, mercurial-devel