tests/test-revert-flags.t

template: add minimal obsfate template function

The goal of this series is to have templates capable of displaying the
evolution of a changeset in a clean and human-readable way.

Add the succsandmarkers template return successors and markers so it can be
used separately like this:

> {succsandmarkers % "{get(succsandmarkers, "markers")|json};"}

The following patches will add template functions that takes successors and
markers as inputs and compute various obsfate fields from them.

#require execbit

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ chmod 644 foo
  $ hg ci -qAm '644'

  $ chmod 755 foo
  $ hg ci -qAm '755'

reverting to rev 0

  $ hg revert -a -r 0
  reverting foo
  $ hg st
  M foo
  $ hg diff --git
  diff --git a/foo b/foo
  old mode 100755
  new mode 100644

  $ cd ..