debugcommands: drop base revision from debugindex Revlog index data consists of generic index metadata that will likely be implemented across all storage engines and revlog-specifc metadata. Most tests printing index data only care about the generic fields. This commit drops the printing of the base revision from `hg debugindex`. This value is an implementation detail of revlogs / delta chains. If tests are interested in verifying this implementation detail, `hg debugdeltachain` is a better command. Most tests were skipping over this field anyway. Tests that weren't looked like they were newer. So my guess is we forgot to make them skip the field to match the style of the older tests. This reinforces my belief that the base revision is not worth having in `hg debugindex`. Differential Revision: https://phab.mercurial-scm.org/D3027

tests: use debugdeltachain where appropriate Some tests are verifying delta chain type things. This metadata has more to do with a revlog implementation details than index data, which is theoretically generic. This commit ports some tests to `hg debugdeltachain`, as it is the more appropriate debug command for looking at delta metadata. Differential Revision: https://phab.mercurial-scm.org/D3026

tests: don't use revlog paths in tests Debug commands operating on revlogs don't need the full revlog path: they can accept the relative path to a tracked file or use -c/-m to specify a changelog or manifest. Not using the revlog path makes tests more resilient to cases where revlogs aren't being used for storage. Differential Revision: https://phab.mercurial-scm.org/D3025

templater: define interface for objects requiring unwrapvalue() unwrapvalue() is changed to not return a lazy bytes generator for "wrapped" types because I want to define the tovalue() interface as such. It's a baby step to unify unwrapvalue() and _unwrapvalue().

templater: extract private function to evaluate generator to byte string

templater: pass (context, mapping) down to unwrapvalue() The same reason as why I made unwraphybrid() take a (context, mapping) pair.

templater: drop unneeded generator from mappable object Per the definition of the show() interface, it can return a bytes.

templater: mark .gen as a private attribute

templatekw: do not directly call .gen

templater: define interface for objects requiring unwraphybrid() Prepares for introducing another hybrid-like data type. show() takes context as an argument so a wrapper class may render its items by pre-configured template: def show(self, context, mapping): return (context.expand(self._tmpl, mapping + lm) for lm in self._mappings)