[PATCH 0/5] usage API: add and use a bug() + BUG_if_bug()

This series adds a bug() (lower-case) function to go along with BUG(). As seen in 2-5/5 this makes it much easier to handle the cases such as parse-options.c where we'd like to call BUG(), but would like to first exhaustively accumulate the N issues we spot before doing so, and not merely BUG() out on the first one.

I have more fixes for parse-options.c queued up on top of this locally, including a fix for one (tiny) recent-ish regression, but found that it was much easier to do so with this new API, as we'll now be able to freely use normal sprintf() formats in these cases, instead of xstrfmt() (where we'd also memory leak).

Ævar Arnfjörð Bjarmason (5):
  usage.c: add a non-fatal bug() function to go with BUG()
  parse-options.c: use new bug() API for optbug()
  parse-options.c: use optbug() instead of BUG() "opts" check
  receive-pack: use bug() and BUG_if_bug()
  cache-tree.c: use bug() and BUG_if_bug()

 .../technical/api-error-handling.txt          | 17 +++++-
 Documentation/technical/api-trace2.txt        |  4 +-
 builtin/receive-pack.c                        | 16 +++---
 cache-tree.c                                  |  7 ++-
 git-compat-util.h                             | 12 +++++
 parse-options.c                               | 50 +++++++++---------
 t/helper/test-trace2.c                        | 21 +++++++-
 t/t0210-trace2-normal.sh                      | 52 +++++++++++++++++++
 trace2.c                                      |  6 +++
 usage.c                                       | 30 +++++++++--
 10 files changed, 165 insertions(+), 50 deletions(-)