emitrevision: add a small closure to check if a base is usable We will make more use of this and make it more complex too.

reuse-delta-base: improves some documentation The current code got me a bit confused initially. So a bit more documentation around it cannot hurt.

branching: merge stable into default

changelog-v2: add a configuration to disable rank computation We encountered a graph where rank computation was pathologically slow. We add an option to disable this computation while this is getting fixed. Disabling the rank computation should allow for testing other changelog-v2 features undisturbed (like changeset-based copy tracing). I am purposely not adding a test for the new non-default code path, as this is a temporary work around of an experimental feature.

debugrevlog: display total stored information This is an interesting statistis, so let's display it.

debug-revlog: details about non-ancestors delta-bases Deltas against a base that is not an ancestor of the revision that owns this delta are notable. For example, they introduce complexity during the bundling process as the base might not exist on the unbundling side. We detect them in `hg debugrevlog` and print information about them.

debug-revlog: move the code in revlogutils module We have a module dedicated to debug code, let us use it.