[PATCH 00/16] worktree: use "git reset --hard" to populate worktree

This is a follow-on series to [1], which migrated "git checkout --to" functionality to "git worktree add". That series continued using "git checkout" for the initial population of the new worktree, which required git-checkout to have too intimate knowledge that it was operating in a newly created worktree.

This series eliminates git-checkout from the picture by instead employing "git reset --hard"[2] to populate the new worktree initially.

It is built atop 1eb07d8 (worktree: add: auto-vivify new branch when <branch> is omitted, 2015-07-06), currently in 'next', which is es/worktree-add except for the final patch (which retires --ignore-other-worktrees) since the intention[3] was to drop that patch.

[1]: http://thread.gmane.org/gmane.comp.version-control.git/273415 [2]: http://thread.gmane.org/gmane.comp.version-control.git/273415/focus=273454 [3]: http://thread.gmane.org/gmane.comp.version-control.git/273415/focus=273585

Eric Sunshine (16):
  checkout: avoid resolving HEAD unnecessarily
  checkout: name check_linked_checkouts() more meaningfully
  checkout: improve die_if_checked_out() robustness
  checkout: die_if_checked_out: simplify strbuf management
  checkout: generalize die_if_checked_out() branch name argument
  branch: publish die_if_checked_out()
  worktree: simplify new branch (-b/-B) option checking
  worktree: introduce options container
  worktree: make --detach mutually exclusive with -b/-B
  worktree: make branch creation distinct from worktree population
  worktree: add_worktree: construct worktree-population command locally
  worktree: detect branch symref/detach and error conditions locally
  worktree: make setup of new HEAD distinct from worktree population
  worktree: avoid resolving HEAD unnecessarily
  worktree: populate via "git reset --hard" rather than "git checkout"
  checkout: drop intimate knowledge of new worktree initial population

 branch.c           |  65 +++++++++++++++++++++++++++++++
 branch.h           |   7 ++++
 builtin/checkout.c |  82 +++------------------------------------
 builtin/worktree.c | 110 +++++++++++++++++++++++++++++++++++------------------
 4 files changed, 151 insertions(+), 113 deletions(-)