[PATCH 0/5] config: support --type=bool-or-auto for "tristate" parsing

Refactor some of our internal C code to use a new git_config_tristate() functino instead of checking for "auto" or "bool" in several places.

This isn't just Yet Another Ævar Series, I'm using this to re-roll my outstanding userdiff series, the start of that topic was a partial refactor of userdiff.c which is better done here.

While writing this I discovered that the recently added --bool-or-type option added in https://lore.kernel.org/git/pull.781.v18.git.git.1599895268433.gitgitgadget@gmail.com/ didn't have any tests (and we didn't notice in 18! iterations of it:)

2/5 adds that, 1/5 adds a comment on some bool parsing code that's puzzled me for the Nth time.

Ævar Arnfjörð Bjarmason (5):
  config.c: add a comment about why value=NULL is true
  config tests: test for --bool-or-str
  git-config: document --bool-or-str and --type=bool-or-str
  config.c: add a "tristate" helper
  config: add --type=bool-or-auto switch

 Documentation/git-config.txt |   7 ++
 builtin/config.c             |  19 ++++++
 builtin/log.c                |  13 ++--
 compat/mingw.c               |   6 +-
 config.c                     |  20 ++++++
 config.h                     |  12 ++++
 http.c                       |   5 +-
 mergetools/meld              |   2 +-
 t/t1300-config.sh            | 121 +++++++++++++++++++++++++++++++++++
 userdiff.c                   |   6 +-
 10 files changed, 195 insertions(+), 16 deletions(-)