[RFC PATCH 0/6] Add gentle alternative for `get_oid()`

At the moment, `get_oid()` might call `die()` in some cases. To prevent that from happening, this patches introduces a new flag called `GET_OID_GENTLY` and a new function `get_oid_gently()`, which passes the mentioned flag further to `get_oid_with_context()`.

The call graph of `get_oid()` is pretty complex and I hope I covered all the cases where `exit()` might be called. Although I believe this series of patches will not introduce any regression and work as intended, I think that is better to mark it with [RFC].

This patch would be useful for converting `git stash` to C. At the moment, `git stash` spawns a child process to avoid `get_oid()` to die. If this series turns out to be good enough to be accepted, do I need to wait until it gets merged in `master` to use it in the other project mentioned before?

Thanks, Paul

Paul-Sebastian Ungureanu (6):
  sha1-name: Add `GET_OID_GENTLY` flag
  tree-walk: Add three new gentle helpers
  refs.c: Teach `read_ref_at()` to accept `GET_OID_GENTLY` flag
  sha1-name: Teach `get_oid_basic()` to be gentle
  sha1-name: Teach `get_oid_with_context[_1]()` to be gentle
  sha1-name: Add gentle alternative for `get_oid()`

 cache.h     |   2 +
 refs.c      |   2 +
 sha1-name.c | 127 +++++++++++++++++++++++++++++++++++++++++-----------
 tree-walk.c | 108 +++++++++++++++++++++++++++++++++++++-------
 tree-walk.h |   3 +-
 5 files changed, 199 insertions(+), 43 deletions(-)