color: fallback and test label as an effect With this changeset, we can now send a color name directly to the label function, e.g. $ hg log -r . -T "{label('red', node|short)}\n"

color: extract method for determining a valid effect This patch is just setup work so that we can reduce code duplication and have one place to define a valid effect.

revlog: use context ancestor instead of changelog ancestor We want to move in this direction.