view tests/test-1102.t @ 27262:3d0feb2f978b

histedit: pick an appropriate base changeset by default (BC)

Previously, `hg histedit` required a revision argument specifying which
revision to use as the base for the current histedit operation. There
was an undocumented and experimental "histedit.defaultrev" option that
supported defining a single revision to be used if no argument is
passed.

Mercurial knows what changesets can be edited. And in most scenarios,
people want to edit this history of everything on the current head that
is rewritable. Making histedit do this by default and not require
an explicit argument or additional configuration is a major usability
win and will enable more people to use histedit.

This patch changes the behavior of the experimental and undocumented
"histedit.defaultrev" config option to select an appropriate base
revision by default. Comprehensive tests exercising the edge cases
in the new, somewhat complicated default revset have been added.
Surprisingly, no tests broke. I guess we were never testing the
behavior with no ANCESTOR argument (it used to fail with
"abort: histedit requires exactly one ancestor revision"). The new
behavior is much more user friendly.

The functionality for choosing the default base revision has been
moved to destutil.py, where it can easily be modified by extensions.

  $ rm -rf a
  $ hg init a
  $ cd a
  $ echo a > a
  $ hg ci -Am0
  adding a
  $ hg tag t1 # 1
  $ hg tag --remove t1 # 2

  $ hg co 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tag -f -r0 t1
  $ hg tags
  tip                                3:a49829c4fc11
  t1                                 0:f7b1eb17ad24

  $ cd ..