[GSoC PATCH v2 0/4] teach git repo info to handle path keys

Hi everyone,

This series teaches `git repo info` to handle `path.*` keys, so scripts can easily discover repository paths.

The commits are divided into 4 parts:

  1. path: extract the path-formatting logic from rev-parse and
     expose it via path.h with a better naming convention.
  2. rev-parse: refactor the command to use the exported function
     and enum.
  3. repo: introduce path.gitdir with standardized tests and docs.
  4. repo: introduce path.commondir.

About patches 3 and 4: In our last discussion [1], we didn't reach a definitive conclusion about paths in repo info, but based on the feedback, explicitly offering both relative and absolute options made the most sense. So, patches 3 and 4 add both `path.<field>.absolute` and `path.<field>.relative` for `gitdir` and `commondir`.

There are still a few open questions. Tagging Justin, Lucas, Junio, Phillip, brian, and Ayush.

Questions:
1. Should there still be a --path-format flag?
2. Should we consider a default option?
   Currently we have path.gitdir.absolute. Should we consider an
   option where a plain `path.gitdir` returns some default?
   If yes:
     2.1 Should we keep the default the same as rev-parse? Or should
         either relative or absolute be the default?
     2.2 When printing using --all, should the default be printed,
         or should we print both absolute and relative?
3. Is printing both absolute and relative in a single call using
   --all acceptable? If no, what's a better approach?

I have discussed these changes with both Justin and Lucas internally and wanted to gather opinions from the wider community before moving forward.

Changes since v1:

* Lucas's feedback: Added corner cases covering GIT_COMMON_DIR and
  GIT_DIR. Parameterized the test helper fields instead of hardcoding
  them. Also fixed the subject prefix to [GSoC PATCH v2].

* Junio's feedback: Added a clearer description of what the series
  does up front. I also realized the commit messages for patches 3
  and 4 explained the "what" and not the "why", so I have (hopefully)
  improved them :)

* Phillip's feedback: Changed the helper function name and combined
  the two enums into one, which made a lot of sense.

  I have also added comments within the path.h files to document
  the API.

* About lexicographical order: "Breaking" wasn't the right term
  before, but I do believe keeping .absolute and .relative as
  suffixes is a better choice. I prefer having the two choices
  side-by-side grouped by entity, rather than a cluster of absolute
  keys followed by relative ones. Open to hearing if the latter is
  preferred!

Thanks for this round of feedback guys, this has been fruitful!

P.S - I realized that I didn't add the link to Lucas's patch thread last time :) sorry bout that!

[1] https://public-inbox.org/git/041DCF2E-75FB-4B0A-9128-FDBB1A6DAC3C@gmail.com/T/#t

K Jayatheerth (4):
  path: introduce format_path() for centralized path formatting
  rev-parse: use format_path for path formatting
  repo: add path.gitdir with absolute and relative suffix formatting
  repo: add path.commondir with absolute and relative suffix formatting

 Documentation/git-repo.adoc |  15 ++++++
 builtin/repo.c              |  50 +++++++++++++++++
 builtin/rev-parse.c         | 103 ++++++++----------------------------
 path.c                      |  58 ++++++++++++++++++++
 path.h                      |  30 +++++++++++
 t/t1900-repo-info.sh        |  40 ++++++++++++++
 6 files changed, 216 insertions(+), 80 deletions(-)