[RFC PATCH 0/5] Introduce -t, --table for status/add commands

This is a proposal / proof-of-concept for a new table-based output format for the git status command, and for dry runs (-n) of the git add command. This could be extended to create visual dry runs for other other commands like rm, mv, restore, stash, commit, and clean.

For some context, earlier this year I released a tool called Git-Sim (https://github.com/initialcommit-com/git-sim) which allows users to do visual dry runs of many Git commands, which are rendered as high quality output image files. Simulating commands like status, add, rm, mv, restore, stash, and commit creates a table with 3 columns to represent the way file changes "move around" as a result of the command being simulated.

I've gotten positive feedback from users about this visual approach to simulating git commands, which is more intuitive than pure terminal text for both newer users to understand how git works and for visual people.

As a result, I was thinking of ways to integrate these types of visual formats directly into Git. A table-based output format with colored highlighting for the commands mentioned above is low hanging fruit.

Teach 'git status' the new -t, --table flag, which displays the status output in a 3-column table format, preserving terminology and color coding from the default git status "long output" format (note that the column headers are shortened here for the small width of this email, and also I just realized that the tables below might not look right on the mailing list due to the differing character width, but it looks correct in the terminal so please test there it's more fun anyway :D):

$ git status -t
-------------------------------------------------------------------------
|    Untracked files    | Changes n...or commit | Changes t...committed |
-------------------------------------------------------------------------
|         poiu          |                       |                       |
|     status-table/     |                       |                       |
|                       |                       |         asdf          |
|                       |        table.c        |                       |
|                       |      wt-status.c      |                       |
-------------------------------------------------------------------------

Teach 'git add' the new -t, --table flag to be used ONLY in combination with the '-n' flag for dry runs. Instead of simply printing out the added filenames, the full status table format is displayed, along with arrows that visually show how the added files are being moved around:

$ git add -nt poiu wt-status.c
-------------------------------------------------------------------------
|    Untracked files    | Changes n...or commit | Changes t...committed |
-------------------------------------------------------------------------
|         poiu -----------------------------------------> poiu          |
|     status-table/     |                       |                       |
|                       |                       |         asdf          |
|                       |        table.c        |                       |
|                       |      wt-status.c ----------> wt-status.c      |
-------------------------------------------------------------------------

Other notes:

* The width of the table and columns are dynamically set based on the
  width of the terminal.

* Long paths are shortened to include the maximum number of characters
  from both ends of the path that will fit, with a '...' in the middle.

* Color coding matches the default output of 'git status', with
  untracked files and working dir mods in red, and staged changes in
  green. If needed, arrows are drawn in cyan.

As stated above, the dry run version of the table format can be applied to various other commands like rm, mv, restore, stash, commit, and clean which all move file changes around in a way that can be represented in the table format. New columns may need to be added or arrows reversed to show changes moving in various directions. Note that some of these commands don't appear to have a dry run (-n) option yet, so it could be added for consistency (if not already in use) and for use with the new table format.

Since this is an RFC patch series, I probably did some illegal and dumb things in my code changes just to get it into a demo-able state. I am a bit wary of having made changes to files like "read-cache.c" and "read-cache-ll.h" to pass in the wt_status info, and there are probably betters ways to do some other things too.

Feedback on both the new format itself and the implementation is very much appreciated!

Jacob Stopak (5):
  status: introduce -t, --table flag
  status: handle long paths with -t, --table flag
  status: add advice arg for -t, --table flag
  add: add -t, --table flag for visual dry runs
  add: set unique color for -t, --table arrows

 Makefile         |   1 +
 builtin/add.c    |  46 +++++++--
 builtin/commit.c |   4 +-
 read-cache-ll.h  |   9 +-
 read-cache.c     |  32 ++++++-
 table.c          | 245 +++++++++++++++++++++++++++++++++++++++++++++++
 table.h          |   6 ++
 wt-status.c      |  74 +++++++++-----
 wt-status.h      |   3 +
 9 files changed, 378 insertions(+), 42 deletions(-)
 create mode 100644 table.c
 create mode 100644 table.h